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Types Reference

Types Reference

All types defined by the library, grouped by category. Types are shown using Rust as the canonical representation.

Result Types

StructuredDataResult

Field Type Default Description
content String — The extracted text content
format String — Format
metadata HashMap<String, String> — Document metadata
text_fields Vec<String> — Text fields

ExtractionResult

General extraction result used by the core extraction API.

This is the main result type returned by all extraction functions.

Field Type Default Description
content String — The extracted text content
mime_type String — The detected MIME type
metadata Metadata — Document metadata
extraction_method Option<ExtractionMethod> Default::default() Extraction strategy used to produce the returned text. Populated when the extractor can reliably distinguish native text extraction, OCR-only extraction, or mixed native/OCR output.
tables Vec<Table> vec![] Tables extracted from the document
detected_languages Vec<String> vec![] Detected languages
chunks Vec<Chunk> vec![] Text chunks when chunking is enabled. When chunking configuration is provided, the content is split into overlapping chunks for efficient processing. Each chunk contains the text, optional embeddings (if enabled), and metadata about its position.
images Vec<ExtractedImage> vec![] Extracted images from the document. When image extraction is enabled via ImageExtractionConfig, this field contains all images found in the document with their raw data and metadata. Each image may optionally contain a nested ocr_result if OCR was performed.
pages Vec<PageContent> vec![] Per-page content when page extraction is enabled. When page extraction is configured, the document is split into per-page content with tables and images mapped to their respective pages.
elements Vec<Element> vec![] Semantic elements when element-based result format is enabled. When result_format is set to ElementBased, this field contains semantic elements with type classification, unique identifiers, and metadata for Unstructured-compatible element-based processing.
djot_content Option<DjotContent> Default::default() Rich Djot content structure (when extracting Djot documents). When extracting Djot documents with structured extraction enabled, this field contains the full semantic structure including: - Block-level elements with nesting - Inline formatting with attributes - Links, images, footnotes - Math expressions - Complete attribute information The content field still contains plain text for backward compatibility. Always None for non-Djot documents.
ocr_elements Vec<OcrElement> vec![] OCR elements with full spatial and confidence metadata. When OCR is performed with element extraction enabled, this field contains the structured representation of detected text including: - Bounding geometry (rectangles or quadrilaterals) - Confidence scores (detection and recognition) - Rotation information - Hierarchical relationships (Tesseract only) This field preserves all metadata that would otherwise be lost when converting to plain text or markdown output formats. Only populated when OcrElementConfig.include_elements is true.
document Option<DocumentStructure> Default::default() Structured document tree (when document structure extraction is enabled). When include_document_structure is true in ExtractionConfig, this field contains the full hierarchical representation of the document including: - Heading-driven section nesting - Table grids with cell-level metadata - Content layer classification (body, header, footer, footnote) - Inline text annotations (formatting, links) - Bounding boxes and page numbers Independent of result_format — can be combined with Unified or ElementBased.
extracted_keywords Vec<Keyword> vec![] Extracted keywords when keyword extraction is enabled. When keyword extraction (RAKE or YAKE) is configured, this field contains the extracted keywords with scores, algorithm info, and position data. Previously stored in metadata.additional["keywords"].
quality_score Option<f64> Default::default() Document quality score from quality analysis. A value between 0.0 and 1.0 indicating the overall text quality. Previously stored in metadata.additional["quality_score"].
processing_warnings Vec<ProcessingWarning> vec![] Non-fatal warnings collected during processing pipeline stages. Captures errors from optional pipeline features (embedding, chunking, language detection, output formatting) that don't prevent extraction but may indicate degraded results. Previously stored as individual keys in metadata.additional.
annotations Vec<PdfAnnotation> vec![] PDF annotations extracted from the document. When annotation extraction is enabled via PdfConfig.extract_annotations, this field contains text notes, highlights, links, stamps, and other annotations found in PDF documents.
children Vec<ArchiveEntry> vec![] Nested extraction results from archive contents. When extracting archives, each processable file inside produces its own full extraction result. Set to None for non-archive formats. Use max_archive_depth in config to control recursion depth.
uris Vec<Uri> vec![] URIs/links discovered during document extraction. Contains hyperlinks, image references, citations, email addresses, and other URI-like references found in the document. Always extracted when present in the source document.
structured_output Option<serde_json::Value> Default::default() Structured extraction output from LLM-based JSON schema extraction. When structured_extraction is configured in ExtractionConfig, the extracted document content is sent to a VLM with the provided JSON schema. The response is parsed and stored here as a JSON value matching the schema.
code_intelligence Option<serde_json::Value> Default::default() Code intelligence results from tree-sitter analysis. Populated when extracting source code files with the tree-sitter feature. Contains metrics, structural analysis, imports/exports, comments, docstrings, symbols, diagnostics, and optionally chunked code segments. Stored as an opaque JSON value so that all language bindings (Go, Java, C#, …) can deserialize it as a raw JSON object rather than a typed struct. The underlying type is tree_sitter_language_pack.ProcessResult.
llm_usage Vec<LlmUsage> vec![] LLM token usage and cost data for all LLM calls made during this extraction. Contains one entry per LLM call. Multiple entries are produced when VLM OCR, structured extraction, or LLM embeddings run during the same extraction. None when no LLM was used.
formatted_content Option<String> Default::default() Pre-rendered content in the requested output format. Populated during derive_extraction_result before tree derivation consumes element data. apply_output_format swaps this into content at the end of the pipeline, after post-processors have operated on plain text.
ocr_internal_document Option<String> Default::default() Structured hOCR document for the OCR+layout pipeline. When tesseract produces hOCR output, the parsed InternalDocument carries paragraph structure with bounding boxes and confidence scores. The layout classification step enriches these elements before final rendering.

XmlExtractionResult

XML extraction result.

Contains extracted text content from XML files along with structural statistics about the XML document.

Field Type Default Description
content String — Extracted text content (XML structure filtered out)
element_count usize — Total number of XML elements processed
unique_elements Vec<String> — List of unique element names found (sorted)

TextExtractionResult

Plain text and Markdown extraction result.

Contains the extracted text along with statistics and, for Markdown files, structural elements like headers and links.

Field Type Default Description
content String — Extracted text content
line_count usize — Number of lines
word_count usize — Number of words
character_count usize — Number of characters
headers Vec<String> None Markdown headers (text only, Markdown files only)
links Vec<Vec<String>> None Markdown links as (text, URL) tuples (Markdown files only)
code_blocks Vec<Vec<String>> None Code blocks as (language, code) tuples (Markdown files only)

PptxExtractionResult

PowerPoint (PPTX) extraction result.

Contains extracted slide content, metadata, and embedded images/tables.

Field Type Default Description
content String — Extracted text content from all slides
metadata PptxMetadata — Presentation metadata
slide_count usize — Total number of slides
image_count usize — Total number of embedded images
table_count usize — Total number of tables
images Vec<ExtractedImage> — Extracted images from the presentation
page_structure Option<PageStructure> None Slide structure with boundaries (when page tracking is enabled)
page_contents Vec<PageContent> None Per-slide content (when page tracking is enabled)
document Option<DocumentStructure> None Structured document representation
hyperlinks Vec<String> /* serde(default) */ Hyperlinks discovered in slides as (url, optional_label) pairs.
office_metadata HashMap<String, String> /* serde(default) */ Office metadata extracted from docProps/core.xml and docProps/app.xml. Contains keys like "title", "author", "created_by", "subject", "keywords", "modified_by", "created_at", "modified_at", etc.

EmailExtractionResult

Email extraction result.

Complete representation of an extracted email message (.eml or .msg) including headers, body content, and attachments.

Field Type Default Description
subject Option<String> None Email subject line
from_email Option<String> None Sender email address
to_emails Vec<String> — Primary recipient email addresses
cc_emails Vec<String> — CC recipient email addresses
bcc_emails Vec<String> — BCC recipient email addresses
date Option<String> None Email date/timestamp
message_id Option<String> None Message-ID header value
plain_text Option<String> None Plain text version of the email body
html_content Option<String> None HTML version of the email body
content String — Cleaned/processed text content. Aliased as cleaned_text for back-compat.
attachments Vec<EmailAttachment> — List of email attachments
metadata HashMap<String, String> — Additional email headers and metadata

OcrExtractionResult

OCR extraction result.

Result of performing OCR on an image or scanned document, including recognized text and detected tables.

Field Type Default Description
content String — Recognized text content
mime_type String — Original MIME type of the processed image
metadata HashMap<String, serde_json::Value> — OCR processing metadata (confidence scores, language, etc.)
tables Vec<OcrTable> — Tables detected and extracted via OCR
ocr_elements Vec<OcrElement> /* serde(default) */ Structured OCR elements with bounding boxes and confidence scores. Available when TSV output is requested or table detection is enabled.
internal_document Option<String> None Structured document produced from hOCR parsing. Carries paragraph structure, bounding boxes, and confidence scores that the flattened content string discards.

OrientationResult

Document orientation detection result.

Field Type Default Description
degrees u32 — Detected orientation in degrees (0, 90, 180, or 270).
confidence f32 — Confidence score (0.0-1.0).

DetectionResult

Page-level detection result containing all detections and page metadata.

Field Type Default Description
page_width u32 — Page width
page_height u32 — Page height
detections Vec<LayoutDetection> — Detections

Configuration Types

See Configuration Reference for detailed defaults and language-specific representations.

AccelerationConfig

Hardware acceleration configuration for ONNX Runtime models.

Controls which execution provider (CPU, CoreML, CUDA, TensorRT) is used for inference in layout detection and embedding generation.

Field Type Default Description
provider ExecutionProviderType ExecutionProviderType::Auto Execution provider to use for ONNX inference.
device_id u32 — GPU device ID (for CUDA/TensorRT). Ignored for CPU/CoreML/Auto.

ContentFilterConfig

Cross-extractor content filtering configuration.

Controls whether "furniture" content (headers, footers, page numbers, watermarks, repeating text) is included in or stripped from extraction results. Applies across all extractors (PDF, DOCX, RTF, ODT, HTML, etc.) with format-specific implementation.

When None on ExtractionConfig, each extractor uses its current default behavior unchanged.

Field Type Default Description
include_headers bool false Include running headers in extraction output. - PDF: Disables top-margin furniture stripping and prevents the layout model from treating PageHeader-classified regions as furniture. - DOCX: Includes document headers in text output. - RTF/ODT: Headers already included; this is a no-op when true. - HTML/EPUB: Keeps <header> element content. Default: false (headers are stripped or excluded).
include_footers bool false Include running footers in extraction output. - PDF: Disables bottom-margin furniture stripping and prevents the layout model from treating PageFooter-classified regions as furniture. - DOCX: Includes document footers in text output. - RTF/ODT: Footers already included; this is a no-op when true. - HTML/EPUB: Keeps <footer> element content. Default: false (footers are stripped or excluded).
strip_repeating_text bool true Enable the heuristic cross-page repeating text detector. When true (default), text that repeats verbatim across a supermajority of pages is classified as furniture and stripped. Disable this if brand names or repeated headings are being incorrectly removed by the heuristic. Note: when a layout-detection model is active, the model may independently classify page-header / page-footer regions as furniture on a per-page basis. To preserve those regions, set include_headers = true, include_footers = true, or both, in addition to disabling this flag. Primarily affects PDF extraction. Default: true.
include_watermarks bool false Include watermark text in extraction output. - PDF: Keeps watermark artifacts and arXiv identifiers. - Other formats: No effect currently. Default: false (watermarks are stripped).

EmailConfig

Configuration for email extraction.

Field Type Default Description
msg_fallback_codepage Option<u32> Default::default() Windows codepage number to use when an MSG file contains no codepage property. Defaults to None, which falls back to windows-1252. If an unrecognized or invalid codepage number is supplied (including 0), the behavior silently falls back to windows-1252 — the same as when the MSG file itself contains an unrecognized codepage. No error or warning is emitted. Users should verify output when supplying unusual values. Common values: - 1250: Central European (Polish, Czech, Hungarian, etc.) - 1251: Cyrillic (Russian, Ukrainian, Bulgarian, etc.) - 1252: Western European (default) - 1253: Greek - 1254: Turkish - 1255: Hebrew - 1256: Arabic - 932: Japanese (Shift-JIS) - 936: Simplified Chinese (GBK)

ExtractionConfig

Main extraction configuration.

This struct contains all configuration options for the extraction process. It can be loaded from TOML, YAML, or JSON files, or created programmatically.

Field Type Default Description
use_cache bool true Enable caching of extraction results
enable_quality_processing bool true Enable quality post-processing
ocr Option<OcrConfig> None OCR configuration (None = OCR disabled)
force_ocr bool false Force OCR even for searchable PDFs
force_ocr_pages Vec<u32> None Force OCR on specific pages only (1-indexed page numbers, must be >= 1). When set, only the listed pages are OCR'd regardless of text layer quality. Unlisted pages use native text extraction. Ignored when force_ocr is true. Only applies to PDF documents. Duplicates are automatically deduplicated. An ocr config is recommended for backend/language selection; defaults are used if absent.
disable_ocr bool false Disable OCR entirely, even for images. When true, OCR is skipped for all document types. Images return metadata only (dimensions, format, EXIF) without text extraction. PDFs use only native text extraction without OCR fallback. Cannot be true simultaneously with force_ocr. Added in v4.7.0.
chunking Option<ChunkingConfig> None Text chunking configuration (None = chunking disabled)
content_filter Option<ContentFilterConfig> None Content filtering configuration (None = use extractor defaults). Controls whether document "furniture" (headers, footers, watermarks, repeating text) is included in or stripped from extraction results. See ContentFilterConfig for per-field documentation.
images Option<ImageExtractionConfig> None Image extraction configuration (None = no image extraction)
pdf_options Option<PdfConfig> None PDF-specific options (None = use defaults)
token_reduction Option<TokenReductionOptions> None Token reduction configuration (None = no token reduction)
language_detection Option<LanguageDetectionConfig> None Language detection configuration (None = no language detection)
pages Option<PageConfig> None Page extraction configuration (None = no page tracking)
keywords Option<KeywordConfig> None Keyword extraction configuration (None = no keyword extraction)
postprocessor Option<PostProcessorConfig> None Post-processor configuration (None = use defaults)
html_options Option<String> None HTML to Markdown conversion options (None = use defaults) Configure how HTML documents are converted to Markdown, including heading styles, list formatting, code block styles, and preprocessing options.
html_output Option<HtmlOutputConfig> None Styled HTML output configuration. When set alongside output_format = OutputFormat.Html, the extraction pipeline uses StyledHtmlRenderer which emits stable kb-* CSS class hooks on every structural element and optionally embeds theme CSS or user-supplied CSS in a <style> block. When None, the existing plain comrak-based HTML renderer is used.
extraction_timeout_secs Option<u64> None Default per-file timeout in seconds for batch extraction. When set, each file in a batch will be canceled after this duration unless overridden by FileExtractionConfig.timeout_secs. None means no timeout (unbounded extraction time).
max_concurrent_extractions Option<usize> None Maximum concurrent extractions in batch operations (None = (num_cpus × 1.5).ceil()). Limits parallelism to prevent resource exhaustion when processing large batches. Defaults to (num_cpus × 1.5).ceil() when not set.
result_format ResultFormat ResultFormat::Unified Result structure format Controls whether results are returned in unified format (default) with all content in the content field, or element-based format with semantic elements (for Unstructured-compatible output).
security_limits Option<SecurityLimits> None Security limits for archive extraction. Controls maximum archive size, compression ratio, file count, and other security thresholds to prevent decompression bomb attacks. Also caps nesting depth, iteration count, entity / token length, total content size, and table cell count for every extraction path that ingests user-controlled bytes. When None, default limits are used.
output_format OutputFormat OutputFormat::Plain Content text format (default: Plain). Controls the format of the extracted content: - Plain: Raw extracted text (default) - Markdown: Markdown formatted output - Djot: Djot markup format (requires djot feature) - Html: HTML formatted output When set to a structured format, extraction results will include formatted output. The formatted_content field may be populated when format conversion is applied.
layout Option<LayoutDetectionConfig> None Layout detection configuration (None = layout detection disabled). When set, PDF pages and images are analyzed for document structure (headings, code, formulas, tables, figures, etc.) using RT-DETR models via ONNX Runtime. For PDFs, layout hints override paragraph classification in the markdown pipeline. For images, per-region OCR is performed with markdown formatting based on detected layout classes. Requires the layout-detection feature to run inference; the field is present whenever the layout-types feature is active (which includes layout-detection as well as the no-ORT target groups).
use_layout_for_markdown bool false Run layout detection on the non-OCR PDF markdown path. When true and layout is Some(_), layout regions inform heading, table, list, and figure detection in the structure pipeline that would otherwise rely on font-clustering heuristics alone. Significantly improves SF1 (structural F1) at the cost of inference latency (~150-300ms/page CPU, ~20-50ms/page GPU). Default: false. Requires the layout-detection feature.
include_document_structure bool false Enable structured document tree output. When true, populates the document field on ExtractionResult with a hierarchical DocumentStructure containing heading-driven section nesting, table grids, content layer classification, and inline annotations. Independent of result_format — can be combined with Unified or ElementBased.
acceleration Option<AccelerationConfig> None Hardware acceleration configuration for ONNX Runtime models. Controls execution provider selection for layout detection and embedding models. When None, uses platform defaults (CoreML on macOS, CUDA on Linux, CPU on Windows).
cache_namespace Option<String> None Cache namespace for tenant isolation. When set, cache entries are stored under {cache_dir}/{namespace}/. Must be alphanumeric, hyphens, or underscores only (max 64 chars). Different namespaces have isolated cache spaces on the same filesystem.
cache_ttl_secs Option<u64> None Per-request cache TTL in seconds. Overrides the global max_age_days for this specific extraction. When 0, caching is completely skipped (no read or write). When None, the global TTL applies.
email Option<EmailConfig> None Email extraction configuration (None = use defaults). Currently supports configuring the fallback codepage for MSG files that do not specify one. See EmailConfig for details.
concurrency Option<String> None Concurrency limits for constrained environments (None = use defaults). Controls Rayon thread pool size, ONNX Runtime intra-op threads, and (when max_concurrent_extractions is unset) the batch concurrency semaphore. See ConcurrencyConfig for details.
max_archive_depth usize — Maximum recursion depth for archive extraction (default: 3). Set to 0 to disable recursive extraction (legacy behavior).
tree_sitter Option<TreeSitterConfig> None Tree-sitter language pack configuration (None = tree-sitter disabled). When set, enables code file extraction using tree-sitter parsers. Controls grammar download behavior and code analysis options.
structured_extraction Option<StructuredExtractionConfig> None Structured extraction via LLM (None = disabled). When set, the extracted document content is sent to an LLM with the provided JSON schema. The structured response is stored in ExtractionResult.structured_output.
cancel_token Option<String> None Cancellation token for this extraction (None = no external cancellation). Pass a CancellationToken clone here and call CancellationToken.cancel from another thread / task to abort the extraction in progress. The extractor checks the token at safe checkpoints (before lock acquisition, between pages, between batch items) and returns KreuzbergError.Cancelled when set. The field is excluded from serialization because CancellationToken is a runtime handle, not a configuration value.

FileExtractionConfig

Per-file extraction configuration overrides for batch processing.

All fields are Option<T> — None means "use the batch-level default." This type is used with batch_extract_files and batch_extract_bytes to allow heterogeneous extraction settings within a single batch.

Excluded Fields

The following ExtractionConfig fields are batch-level only and cannot be overridden per file:

  • max_concurrent_extractions — controls batch parallelism
  • use_cache — global caching policy
  • acceleration — shared ONNX execution provider
  • security_limits — global archive security policy
Field Type Default Description
enable_quality_processing Option<bool> Default::default() Override quality post-processing for this file.
ocr Option<OcrConfig> Default::default() Override OCR configuration for this file (None in the Option = use batch default).
force_ocr Option<bool> Default::default() Override force OCR for this file.
force_ocr_pages Vec<u32> vec![] Override force OCR pages for this file (1-indexed page numbers).
disable_ocr Option<bool> Default::default() Override disable OCR for this file.
chunking Option<ChunkingConfig> Default::default() Override chunking configuration for this file.
content_filter Option<ContentFilterConfig> Default::default() Override content filtering configuration for this file.
images Option<ImageExtractionConfig> Default::default() Override image extraction configuration for this file.
pdf_options Option<PdfConfig> Default::default() Override PDF options for this file.
token_reduction Option<TokenReductionOptions> Default::default() Override token reduction for this file.
language_detection Option<LanguageDetectionConfig> Default::default() Override language detection for this file.
pages Option<PageConfig> Default::default() Override page extraction for this file.
keywords Option<KeywordConfig> Default::default() Override keyword extraction for this file.
postprocessor Option<PostProcessorConfig> Default::default() Override post-processor for this file.
html_options Option<String> Default::default() Override HTML conversion options for this file.
result_format Option<ResultFormat> Default::default() Override result format for this file.
output_format Option<OutputFormat> Default::default() Override output content format for this file.
include_document_structure Option<bool> Default::default() Override document structure output for this file.
layout Option<LayoutDetectionConfig> Default::default() Override layout detection for this file.
timeout_secs Option<u64> Default::default() Override per-file extraction timeout in seconds. When set, the extraction for this file will be canceled after the specified duration. A timed-out file produces an error result without affecting other files in the batch.
tree_sitter Option<TreeSitterConfig> Default::default() Override tree-sitter configuration for this file.
structured_extraction Option<StructuredExtractionConfig> Default::default() Override structured extraction configuration for this file. When set, enables LLM-based structured extraction with a JSON schema for this specific file. The extracted content is sent to a VLM/LLM and the response is parsed according to the provided schema.

ImageExtractionConfig

Image extraction configuration.

Field Type Default Description
extract_images bool true Extract images from documents
target_dpi i32 300 Target DPI for image normalization
max_image_dimension i32 4096 Maximum dimension for images (width or height)
inject_placeholders bool true Whether to inject image reference placeholders into markdown output. When true (default), image references like ![Image 1](embedded:p1_i0) are appended to the markdown. Set to false to extract images as data without polluting the markdown output.
auto_adjust_dpi bool true Automatically adjust DPI based on image content
min_dpi i32 72 Minimum DPI threshold
max_dpi i32 600 Maximum DPI threshold
max_images_per_page Option<u32> None Maximum number of image objects to extract per PDF page. Some PDFs (e.g. technical diagrams stored as thousands of raster fragments) can trigger extremely long or indefinite extraction times when every image object on a dense page is decoded individually via the PDF extractor. Setting this limit causes kreuzberg to stop collecting individual images once the count per page reaches the cap and emit a warning instead. None (default) means no limit — all images are extracted.
classify bool true When true (default), extracted images are classified by kind and grouped into clusters where they appear to belong to one figure.

TokenReductionOptions

Token reduction configuration.

Field Type Default Description
mode String — Reduction mode: "off", "light", "moderate", "aggressive", "maximum"
preserve_important_words bool true Preserve important words (capitalized, technical terms)

LanguageDetectionConfig

Language detection configuration.

Field Type Default Description
enabled bool true Enable language detection
min_confidence f64 0.8 Minimum confidence threshold (0.0-1.0)
detect_multiple bool false Detect multiple languages in the document

HtmlOutputConfig

Configuration for styled HTML output.

When set on ExtractionConfig.html_output alongside output_format = OutputFormat.Html, the pipeline builds a StyledHtmlRenderer instead of the plain comrak-based renderer.

Field Type Default Description
css Option<String> None Inline CSS string injected into the output after the theme stylesheet. Concatenated after css_file content when both are set.
css_file Option<PathBuf> None Path to a CSS file loaded once at renderer construction time. Concatenated before css when both are set.
theme HtmlTheme HtmlTheme::Unstyled Built-in colour/typography theme. Default: HtmlTheme.Unstyled.
class_prefix String — CSS class prefix applied to every emitted class name. Default: "kb-". Change this if your host application already uses classes that start with kb-.
embed_css bool true When true (default), write the resolved CSS into a <style> block immediately after the opening <div class="{prefix}doc">. Set to false to emit only the structural markup and wire up your own stylesheet targeting the kb-* class names.

LayoutDetectionConfig

Layout detection configuration.

Controls layout detection behavior in the extraction pipeline. When set on ExtractionConfig, layout detection is enabled for PDF extraction.

Field Type Default Description
confidence_threshold Option<f32> None Confidence threshold override (None = use model default).
apply_heuristics bool true Whether to apply postprocessing heuristics (default: true).
table_model TableModel TableModel::Tatr Table structure recognition model. Controls which model is used for table cell detection within layout-detected table regions. Defaults to TableModel.Tatr.
acceleration Option<AccelerationConfig> None Hardware acceleration for ONNX models (layout detection + table structure). When set, controls which execution provider (CPU, CUDA, CoreML, TensorRT) is used for inference. Defaults to None (auto-select per platform).

LlmConfig

Configuration for an LLM provider/model via liter-llm.

Each feature (VLM OCR, VLM embeddings, structured extraction) carries its own LlmConfig, allowing different providers per feature.

Field Type Default Description
model String — Provider/model string using liter-llm routing format. Examples: "openai/gpt-4o", "anthropic/claude-sonnet-4-20250514", "groq/llama-3.1-70b-versatile".
api_key Option<String> Default::default() API key for the provider. When None, liter-llm falls back to the provider's standard environment variable (e.g., OPENAI_API_KEY).
base_url Option<String> Default::default() Custom base URL override for the provider endpoint.
timeout_secs Option<u64> Default::default() Request timeout in seconds (default: 60).
max_retries Option<u32> Default::default() Maximum retry attempts (default: 3).
temperature Option<f64> Default::default() Sampling temperature for generation tasks.
max_tokens Option<u64> Default::default() Maximum tokens to generate.

StructuredExtractionConfig

Configuration for LLM-based structured data extraction.

Sends extracted document content to a VLM with a JSON schema, returning structured data that conforms to the schema.

Field Type Default Description
schema serde_json::Value — JSON Schema defining the desired output structure.
schema_name String /* serde(default) */ Schema name passed to the LLM's structured output mode.
schema_description Option<String> /* serde(default) */ Optional schema description for the LLM.
strict bool /* serde(default) */ Enable strict mode — output must exactly match the schema.
prompt Option<String> /* serde(default) */ Custom Jinja2 extraction prompt template. When None, a default template is used. Available template variables: - {{ content }} — The extracted document text. - {{ schema }} — The JSON schema as a formatted string. - {{ schema_name }} — The schema name. - {{ schema_description }} — The schema description (may be empty).
llm LlmConfig — LLM configuration for the extraction.

OcrQualityThresholds

Quality thresholds for OCR fallback decisions and pipeline quality gating.

All fields default to the values that match the previous hardcoded behavior, so OcrQualityThresholds.default() preserves existing semantics exactly.

Field Type Default Description
min_total_non_whitespace usize 64 Minimum total non-whitespace characters to consider text substantive.
min_non_whitespace_per_page f64 32 Minimum non-whitespace characters per page on average.
min_meaningful_word_len usize 4 Minimum character count for a word to be "meaningful".
min_meaningful_words usize 3 Minimum count of meaningful words before text is accepted.
min_alnum_ratio f64 0.3 Minimum alphanumeric ratio (non-whitespace chars that are alphanumeric).
min_garbage_chars usize 5 Minimum Unicode replacement characters (U+FFFD) to trigger OCR fallback.
max_fragmented_word_ratio f64 0.6 Maximum fraction of short (1-2 char) words before text is considered fragmented.
critical_fragmented_word_ratio f64 0.8 Critical fragmentation threshold — triggers OCR regardless of meaningful words. Normal English text has ~20-30% short words. 80%+ is definitive garbage.
min_avg_word_length f64 2 Minimum average word length. Below this with enough words indicates garbled extraction.
min_words_for_avg_length_check usize 50 Minimum word count before average word length check applies.
min_consecutive_repeat_ratio f64 0.08 Minimum consecutive word repetition ratio to detect column scrambling.
min_words_for_repeat_check usize 50 Minimum word count before consecutive repetition check is applied.
substantive_min_chars usize 100 Minimum character count for "substantive markdown" OCR skip gate.
non_text_min_chars usize 20 Minimum character count for "non-text content" OCR skip gate.
alnum_ws_ratio_threshold f64 0.4 Alphanumeric+whitespace ratio threshold for skip decisions.
pipeline_min_quality f64 0.5 Minimum quality score (0.0-1.0) for a pipeline stage result to be accepted. If the result from a backend scores below this, try the next backend.

OcrPipelineConfig

Multi-backend OCR pipeline with quality-based fallback.

Backends are tried in priority order (highest first). After each backend produces output, quality is evaluated. If it meets quality_thresholds.pipeline_min_quality, the result is accepted. Otherwise the next backend is tried.

Field Type Default Description
stages Vec<OcrPipelineStage> — Ordered list of backends to try. Sorted by priority (descending) at runtime.
quality_thresholds OcrQualityThresholds /* serde(default) */ Quality thresholds for deciding whether to accept a result or try the next backend.

OcrConfig

OCR configuration.

Field Type Default Description
enabled bool true Whether OCR is enabled. Setting enabled: false is a shorthand for disable_ocr: true on the parent ExtractionConfig. Images return metadata only; PDFs use native text extraction without OCR fallback. Defaults to true. When false, all other OCR settings are ignored.
backend String — OCR backend: tesseract, easyocr, paddleocr
language String — Language code (e.g., "eng", "deu")
tesseract_config Option<TesseractConfig> None Tesseract-specific configuration (optional)
output_format Option<OutputFormat> None Output format for OCR results (optional, for format conversion)
paddle_ocr_config Option<serde_json::Value> None PaddleOCR-specific configuration (optional, JSON passthrough)
backend_options Option<serde_json::Value> None Arbitrary per-call options passed through to the backend unchanged. Custom OCR backends and built-in backends that support runtime tuning can read this value and deserialize the keys they care about. Keys unknown to the backend are silently ignored. This is the recommended extension point for per-call parameters that are not covered by the typed fields above (e.g. mode switching, preprocessing flags, inference batch size). Scope: when pipeline is None, this value is propagated to the primary stage of the auto-constructed pipeline. When pipeline is explicitly set, this field has no effect — the caller must set OcrPipelineStage.backend_options directly on the relevant stage(s) instead. Example: json { "mode": "fast", "enable_layout": true, "timeout_ms": 5000 }
element_config Option<OcrElementConfig> None OCR element extraction configuration
quality_thresholds Option<OcrQualityThresholds> None Quality thresholds for the native-text-to-OCR fallback decision. When None, uses compiled defaults (matching previous hardcoded behavior).
pipeline Option<OcrPipelineConfig> None Multi-backend OCR pipeline configuration. When set, enables weighted fallback across multiple OCR backends based on output quality. When None, uses the single backend field (same as today).
auto_rotate bool false Enable automatic page rotation based on orientation detection. When enabled, uses Tesseract's DetectOrientationScript() to detect page orientation (0/90/180/270 degrees) before OCR. If the page is rotated with high confidence, the image is corrected before recognition. This is critical for handling rotated scanned documents.
vlm_config Option<LlmConfig> None VLM (Vision Language Model) OCR configuration. Required when backend is "vlm". Uses liter-llm to send page images to a vision model for text extraction.
vlm_prompt Option<String> None Custom Jinja2 prompt template for VLM OCR. When None, uses the default template. Available variables: - {{ language }} — The document language code (e.g., "eng", "deu").
acceleration Option<AccelerationConfig> None Hardware acceleration for ONNX Runtime models (e.g. PaddleOCR, layout detection). Not user-configurable via config files — injected at runtime from ExtractionConfig.acceleration before each process_image call.
tessdata_bytes HashMap<String, Vec<u8>> None Caller-supplied Tesseract traineddata bytes per language code. Primary use case is the WASM build, which has no filesystem and cannot download tessdata at runtime. Native builds typically rely on TessdataManager and ignore this field. When present, the WASM Tesseract backend prefers these bytes over its compile-time-bundled English data. Skipped by serde to keep config files small — supply via the typed API at runtime.

PageConfig

Page extraction and tracking configuration.

Controls how pages are extracted, tracked, and represented in the extraction results. When None, page tracking is disabled.

Page range tracking in chunk metadata (first_page/last_page) is automatically enabled when page boundaries are available and chunking is configured.

Field Type Default Description
extract_pages bool false Extract pages as separate array (ExtractionResult.pages)
insert_page_markers bool false Insert page markers in main content string
marker_format String `"

"` | Page marker format (use {page_num} placeholder) Default: "\n\n\n\n" |

PdfConfig

PDF-specific configuration.

Field Type Default Description
extract_images bool false Extract images from PDF
extract_tables bool true Extract tables from PDF. When true (default), runs pdf_oxide's native grid detector and, if it finds nothing, falls back to the heuristic text-layer reconstruction in pdf.oxide.table.extract_tables_heuristic. Set to false to skip both passes — tables will then be empty in the result.
passwords Vec<String> None List of passwords to try when opening encrypted PDFs
extract_metadata bool true Extract PDF metadata
hierarchy Option<HierarchyConfig> None Hierarchy extraction configuration (None = hierarchy extraction disabled)
extract_annotations bool false Extract PDF annotations (text notes, highlights, links, stamps). Default: false
top_margin_fraction Option<f32> None Top margin fraction (0.0–1.0) of page height to exclude headers/running heads. Default: 0.06 (6%)
bottom_margin_fraction Option<f32> None Bottom margin fraction (0.0–1.0) of page height to exclude footers/page numbers. Default: 0.05 (5%)
allow_single_column_tables bool false Allow single-column pseudo tables in extraction results. By default, tables with fewer than 2 columns (layout-guided) or 3 columns (heuristic) are rejected. When true, the minimum column count is relaxed to 1, allowing single-column structured data (glossaries, itemized lists) to be emitted as tables. Other quality filters (density, sparsity, prose detection) still apply.
ocr_inline_images bool false Perform OCR on inline images extracted from PDF pages and attach the recognized text to each ExtractedImage.ocr_result. Requires Tesseract to be available; if ExtractionConfig.ocr is None the extractor falls back to TesseractConfig.default(). Per-image failures degrade gracefully (the image is returned without OCR text rather than failing the whole extraction). Default: false.

HierarchyConfig

Hierarchy extraction configuration for PDF text structure analysis.

Enables extraction of document hierarchy levels (H1-H6) based on font size clustering and semantic analysis. When enabled, hierarchical blocks are included in page content.

Field Type Default Description
enabled bool true Enable hierarchy extraction
k_clusters usize 3 Number of font size clusters to use for hierarchy levels (1-7) Default: 6, which provides H1-H6 heading levels with body text. Larger values create more fine-grained hierarchy levels.
include_bbox bool true Include bounding box information in hierarchy blocks
ocr_coverage_threshold Option<f32> None OCR coverage threshold for smart OCR triggering (0.0-1.0) Determines when OCR should be triggered based on text block coverage. OCR is triggered when text blocks cover less than this fraction of the page. Default: 0.5 (trigger OCR if less than 50% of page has text)

PostProcessorConfig

Post-processor configuration.

Field Type Default Description
enabled bool true Enable post-processors
enabled_processors Vec<String> None Whitelist of processor names to run (None = all enabled)
disabled_processors Vec<String> None Blacklist of processor names to skip (None = none disabled)
enabled_set Vec<String> None Pre-computed AHashSet for O(1) enabled processor lookup
disabled_set Vec<String> None Pre-computed AHashSet for O(1) disabled processor lookup

ChunkingConfig

Chunking configuration.

Configures text chunking for document content, including chunk size, overlap, trimming behavior, and optional embeddings.

Use ..the default constructor when constructing to allow for future field additions:

Field Type Default Description
max_characters usize 1000 Maximum size per chunk (in units determined by sizing). When sizing is Characters (default), this is the max character count. When using token-based sizing, this is the max token count. Default: 1000
overlap usize 200 Overlap between chunks (in units determined by sizing). Default: 200
trim bool true Whether to trim whitespace from chunk boundaries. Default: true
chunker_type ChunkerType ChunkerType::Text Type of chunker to use (Text or Markdown). Default: Text
embedding Option<EmbeddingConfig> None Optional embedding configuration for chunk embeddings.
preset Option<String> None Use a preset configuration (overrides individual settings if provided).
sizing ChunkSizing ChunkSizing::Characters How to measure chunk size. Default: Characters (Unicode character count). Enable chunking-tiktoken or chunking-tokenizers features for token-based sizing.
prepend_heading_context bool false When true and chunker_type is Markdown, prepend the heading hierarchy path (e.g. "# Title > ## Section\n\n") to each chunk's content string. This is useful for RAG pipelines where each chunk needs self-contained context about its position in the document structure. Default: false
topic_threshold Option<f32> None Optional cosine similarity threshold for semantic topic boundary detection. Only used when chunker_type is Semantic and an EmbeddingConfig is provided. You almost never need to set this. When omitted, defaults to 0.75 which works well for most documents. Lower values detect more topic boundaries (more, smaller chunks); higher values detect fewer. Range: 0.0..=1.0.

EmbeddingConfig

Embedding configuration for text chunks.

Configures embedding generation using ONNX models via the vendored embedding engine. Requires the embeddings feature to be enabled.

Field Type Default Description
model EmbeddingModelType EmbeddingModelType::Preset The embedding model to use (defaults to "balanced" preset if not specified)
normalize bool true Whether to normalize embedding vectors (recommended for cosine similarity)
batch_size usize 32 Batch size for embedding generation
show_download_progress bool false Show model download progress
cache_dir Option<PathBuf> None Custom cache directory for model files Defaults to ~/.cache/kreuzberg/embeddings/ if not specified. Allows full customization of model download location.
acceleration Option<AccelerationConfig> None Hardware acceleration for the embedding ONNX model. When set, controls which execution provider (CPU, CUDA, CoreML, TensorRT) is used for inference. Defaults to None (auto-select per platform).
max_embed_duration_secs Option<u64> Default::default() Maximum wall-clock duration (in seconds) for a single embed() call when using EmbeddingModelType.Plugin. Applies only to the in-process plugin path — protects against hung host-language backends (e.g. a Python callback deadlocked on the GIL, a model stuck on CUDA OOM retries, etc.). On timeout, the dispatcher returns Plugin instead of blocking forever. None disables the timeout. The default (60 seconds) is conservative for common in-process inference; increase for large batches on slow hardware.

TreeSitterConfig

Configuration for tree-sitter language pack integration.

Controls grammar download behavior and code analysis options.

Example (TOML)

[tree_sitter]
languages = ["python", "rust"]
groups = ["web"]

[tree_sitter.process]
structure = true
comments = true
docstrings = true
Field Type Default Description
enabled bool true Enable code intelligence processing (default: true). When false, tree-sitter analysis is completely skipped even if the config section is present.
cache_dir Option<PathBuf> None Custom cache directory for downloaded grammars. When None, uses the default: ~/.cache/tree-sitter-language-pack/v{version}/libs/.
languages Vec<String> None Languages to pre-download on init (e.g., ["python", "rust"]).
groups Vec<String> None Language groups to pre-download (e.g., ["web", "systems", "scripting"]).
process TreeSitterProcessConfig — Processing options for code analysis.

TreeSitterProcessConfig

Processing options for tree-sitter code analysis.

Controls which analysis features are enabled when extracting code files.

Field Type Default Description
structure bool true Extract structural items (functions, classes, structs, etc.). Default: true.
imports bool true Extract import statements. Default: true.
exports bool true Extract export statements. Default: true.
comments bool false Extract comments. Default: false.
docstrings bool false Extract docstrings. Default: false.
symbols bool false Extract symbol definitions. Default: false.
diagnostics bool false Include parse diagnostics. Default: false.
chunk_max_size Option<usize> None Maximum chunk size in bytes. None disables chunking.
content_mode CodeContentMode CodeContentMode::Chunks Content rendering mode for code extraction.

ServerConfig

API server configuration.

This struct holds all configuration options for the Kreuzberg API server, including host/port settings, CORS configuration, and upload limits.

Defaults

  • host: "127.0.0.1" (localhost only)
  • port: 8000
  • cors_origins: empty vector (allows all origins)
  • max_request_body_bytes: 104_857_600 (100 MB)
  • max_multipart_field_bytes: 104_857_600 (100 MB)
Field Type Default Description
host String — Server host address (e.g., "127.0.0.1", "0.0.0.0")
port u16 — Server port number
cors_origins Vec<String> vec![] CORS allowed origins. Empty vector means allow all origins. If this is an empty vector, the server will accept requests from any origin. If populated with specific origins (e.g., "<https://example.com">), only those origins will be allowed.
max_request_body_bytes usize — Maximum size of request body in bytes (default: 100 MB)
max_multipart_field_bytes usize — Maximum size of multipart fields in bytes (default: 100 MB)

DocxAppProperties

Application properties from docProps/app.xml for DOCX

Contains Word-specific document statistics and metadata.

Field Type Default Description
application Option<String> Default::default() Application name (e.g., "Microsoft Office Word")
app_version Option<String> Default::default() Application version
template Option<String> Default::default() Template filename
total_time Option<i32> Default::default() Total editing time in minutes
pages Option<i32> Default::default() Number of pages
words Option<i32> Default::default() Number of words
characters Option<i32> Default::default() Number of characters (excluding spaces)
characters_with_spaces Option<i32> Default::default() Number of characters (including spaces)
lines Option<i32> Default::default() Number of lines
paragraphs Option<i32> Default::default() Number of paragraphs
company Option<String> Default::default() Company name
doc_security Option<i32> Default::default() Document security level
scale_crop Option<bool> Default::default() Scale crop flag
links_up_to_date Option<bool> Default::default() Links up to date flag
shared_doc Option<bool> Default::default() Shared document flag
hyperlinks_changed Option<bool> Default::default() Hyperlinks changed flag

XlsxAppProperties

Application properties from docProps/app.xml for XLSX

Contains Excel-specific document metadata.

Field Type Default Description
application Option<String> Default::default() Application name (e.g., "Microsoft Excel")
app_version Option<String> Default::default() Application version
doc_security Option<i32> Default::default() Document security level
scale_crop Option<bool> Default::default() Scale crop flag
links_up_to_date Option<bool> Default::default() Links up to date flag
shared_doc Option<bool> Default::default() Shared document flag
hyperlinks_changed Option<bool> Default::default() Hyperlinks changed flag
company Option<String> Default::default() Company name
worksheet_names Vec<String> vec![] Worksheet names

PptxAppProperties

Application properties from docProps/app.xml for PPTX

Contains PowerPoint-specific document metadata.

Field Type Default Description
application Option<String> Default::default() Application name (e.g., "Microsoft Office PowerPoint")
app_version Option<String> Default::default() Application version
total_time Option<i32> Default::default() Total editing time in minutes
company Option<String> Default::default() Company name
doc_security Option<i32> Default::default() Document security level
scale_crop Option<bool> Default::default() Scale crop flag
links_up_to_date Option<bool> Default::default() Links up to date flag
shared_doc Option<bool> Default::default() Shared document flag
hyperlinks_changed Option<bool> Default::default() Hyperlinks changed flag
slides Option<i32> Default::default() Number of slides
notes Option<i32> Default::default() Number of notes
hidden_slides Option<i32> Default::default() Number of hidden slides
multimedia_clips Option<i32> Default::default() Number of multimedia clips
presentation_format Option<String> Default::default() Presentation format (e.g., "Widescreen", "Standard")
slide_titles Vec<String> vec![] Slide titles

CoreProperties

Dublin Core metadata from docProps/core.xml

Contains standard metadata fields defined by the Dublin Core standard and Office-specific extensions.

Field Type Default Description
title Option<String> Default::default() Document title
subject Option<String> Default::default() Document subject/topic
creator Option<String> Default::default() Document creator/author
keywords Option<String> Default::default() Keywords or tags
description Option<String> Default::default() Document description/abstract
last_modified_by Option<String> Default::default() User who last modified the document
revision Option<String> Default::default() Revision number
created Option<String> Default::default() Creation timestamp (ISO 8601)
modified Option<String> Default::default() Last modification timestamp (ISO 8601)
category Option<String> Default::default() Document category
content_status Option<String> Default::default() Content status (Draft, Final, etc.)
language Option<String> Default::default() Document language
identifier Option<String> Default::default() Unique identifier
version Option<String> Default::default() Document version
last_printed Option<String> Default::default() Last print timestamp (ISO 8601)

SecurityLimits

Configuration for security limits across extractors.

All limits are intentionally conservative to prevent DoS attacks while still supporting legitimate documents.

Field Type Default Description
max_archive_size usize 524288000 Maximum uncompressed size for archives (500 MB)
max_compression_ratio usize 100 Maximum compression ratio before flagging as potential bomb (100:1)
max_files_in_archive usize 10000 Maximum number of files in archive (10,000)
max_nesting_depth usize 1024 Maximum nesting depth for structures (100)
max_entity_length usize 1048576 Maximum length of any single XML entity / attribute / token (1 MiB). This is a per-token cap, NOT a total cap — billion-laughs class attacks where a single entity expands to hundreds of MB are caught here, while normal long text content (a paragraph, a CDATA block) is caught by max_content_size instead.
max_content_size usize 104857600 Maximum string growth per document (100 MB)
max_iterations usize 10000000 Maximum iterations per operation
max_xml_depth usize 1024 Maximum XML depth (100 levels)
max_table_cells usize 100000 Maximum cells per table (100,000)

TokenReductionConfig

Field Type Default Description
level ReductionLevel ReductionLevel::Moderate Level (reduction level)
language_hint Option<String> None Language hint
preserve_markdown bool false Preserve markdown
preserve_code bool true Preserve code
semantic_threshold f32 0.3 Semantic threshold
enable_parallel bool true Enable parallel
use_simd bool true Use simd
custom_stopwords HashMap<String, Vec<String>> None Custom stopwords
preserve_patterns Vec<String> vec![] Preserve patterns
target_reduction Option<f32> None Target reduction
enable_semantic_clustering bool false Enable semantic clustering

DocumentStructure

Top-level structured document representation.

A flat array of nodes with index-based parent/child references forming a tree. Root-level nodes have parent: None. Use body_roots() and furniture_roots() to iterate over top-level content by layer.

Validation

Call validate() after construction to verify all node indices are in bounds and parent-child relationships are bidirectionally consistent.

Field Type Default Description
nodes Vec<DocumentNode> vec![] All nodes in document/reading order.
source_format Option<String> Default::default() Origin format identifier (e.g. "docx", "pptx", "html", "pdf"). Allows renderers to apply format-aware heuristics when converting the document tree to output formats.
relationships Vec<DocumentRelationship> vec![] Resolved relationships between nodes (footnote refs, citations, anchor links, etc.). Populated during derivation from the internal document representation. Empty when no relationships are detected.
node_types Vec<String> vec![] Sorted, deduplicated list of node type names present in this document. Each value is the snake_case node_type tag of the corresponding NodeContent variant (e.g. "paragraph", "heading", "table", …). Computed from nodes via DocumentStructure.finalize_node_types. Empty until that method is called (internal construction paths call it at the end of derivation).

TableGrid

Structured table grid with cell-level metadata.

Stores row/column dimensions and a flat list of cells with position info.

Field Type Default Description
rows u32 — Number of rows in the table.
cols u32 — Number of columns in the table.
cells Vec<GridCell> vec![] All cells in row-major order.

LlmUsage

Token usage and cost data for a single LLM call made during extraction.

Populated when VLM OCR, structured extraction, or LLM-based embeddings are used. Multiple entries may be present when multiple LLM calls occur within one extraction (e.g. VLM OCR + structured extraction).

Field Type Default Description
model String — The LLM model identifier (e.g. "openai/gpt-4o", "anthropic/claude-sonnet-4-20250514").
source String — The pipeline stage that triggered this LLM call (e.g. "vlm_ocr", "structured_extraction", "embeddings").
input_tokens Option<u64> Default::default() Number of input/prompt tokens consumed.
output_tokens Option<u64> Default::default() Number of output/completion tokens generated.
total_tokens Option<u64> Default::default() Total tokens (input + output).
estimated_cost Option<f64> Default::default() Estimated cost in USD based on the provider's published pricing.
finish_reason Option<String> Default::default() Why the model stopped generating (e.g. "stop", "length", "content_filter").

BoundingBox

Bounding box coordinates for element positioning.

Field Type Default Description
x0 f64 — Left x-coordinate
y0 f64 — Bottom y-coordinate
x1 f64 — Right x-coordinate
y1 f64 — Top y-coordinate

ImagePreprocessingConfig

Image preprocessing configuration for OCR.

These settings control how images are preprocessed before OCR to improve text recognition quality. Different preprocessing strategies work better for different document types.

Field Type Default Description
target_dpi i32 300 Target DPI for the image (300 is standard, 600 for small text).
auto_rotate bool true Auto-detect and correct image rotation.
deskew bool true Correct skew (tilted images).
denoise bool false Remove noise from the image.
contrast_enhance bool false Enhance contrast for better text visibility.
binarization_method String "otsu" Binarization method: "otsu", "sauvola", "adaptive".
invert_colors bool false Invert colors (white text on black → black on white).

TesseractConfig

Tesseract OCR configuration.

Provides fine-grained control over Tesseract OCR engine parameters. Most users can use the defaults, but these settings allow optimization for specific document types (invoices, handwriting, etc.).

Field Type Default Description
language String "eng" Language code (e.g., "eng", "deu", "fra")
psm i32 3 Page Segmentation Mode (0-13). Common values: - 3: Fully automatic page segmentation (native default) - 6: Assume a single uniform block of text (WASM default — avoids layout-analysis hang) - 11: Sparse text with no particular order
output_format String "markdown" Output format ("text" or "markdown")
oem i32 3 OCR Engine Mode (0-3). - 0: Legacy engine only - 1: Neural nets (LSTM) only (usually best) - 2: Legacy + LSTM - 3: Default (based on what's available)
min_confidence f64 0 Minimum confidence threshold (0.0-100.0). Words with confidence below this threshold may be rejected or flagged.
preprocessing Option<ImagePreprocessingConfig> None Image preprocessing configuration. Controls how images are preprocessed before OCR. Can significantly improve quality for scanned documents or low-quality images.
enable_table_detection bool true Enable automatic table detection and reconstruction
table_min_confidence f64 0 Minimum confidence threshold for table detection (0.0-1.0)
table_column_threshold i32 50 Column threshold for table detection (pixels)
table_row_threshold_ratio f64 0.5 Row threshold ratio for table detection (0.0-1.0)
use_cache bool true Enable OCR result caching
classify_use_pre_adapted_templates bool true Use pre-adapted templates for character classification
language_model_ngram_on bool false Enable N-gram language model
tessedit_dont_blkrej_good_wds bool true Don't reject good words during block-level processing
tessedit_dont_rowrej_good_wds bool true Don't reject good words during row-level processing
tessedit_enable_dict_correction bool true Enable dictionary correction
tessedit_char_whitelist String "" Whitelist of allowed characters (empty = all allowed)
tessedit_char_blacklist String "" Blacklist of forbidden characters (empty = none forbidden)
tessedit_use_primary_params_model bool true Use primary language params model
textord_space_size_is_variable bool true Variable-width space detection
thresholding_method bool false Use adaptive thresholding method

OcrConfidence

Confidence scores for an OCR element.

Separates detection confidence (how confident that text exists at this location) from recognition confidence (how confident about the actual text content).

Field Type Default Description
detection Option<f64> Default::default() Detection confidence: how confident the OCR engine is that text exists here. PaddleOCR provides this as box_score, Tesseract doesn't have a direct equivalent. Range: 0.0 to 1.0 (or None if not available).
recognition f64 — Recognition confidence: how confident about the text content. Range: 0.0 to 1.0.

OcrElement

A unified OCR element representing detected text with full metadata.

This is the primary type for structured OCR output, preserving all information from both Tesseract and PaddleOCR backends.

Field Type Default Description
text String — The recognized text content.
geometry OcrBoundingGeometry OcrBoundingGeometry::Rectangle Bounding geometry (rectangle or quadrilateral).
confidence OcrConfidence — Confidence scores for detection and recognition.
level OcrElementLevel OcrElementLevel::Line Hierarchical level (word, line, block, page).
rotation Option<OcrRotation> Default::default() Rotation information (if detected).
page_number u32 — Page number (1-indexed).
parent_id Option<String> Default::default() Parent element ID for hierarchical relationships. Only used for Tesseract output which has word -> line -> block hierarchy.
backend_metadata HashMap<String, serde_json::Value> HashMap::new() Backend-specific metadata that doesn't fit the unified schema.

OcrElementConfig

Configuration for OCR element extraction.

Controls how OCR elements are extracted and filtered.

Field Type Default Description
include_elements bool — Whether to include OCR elements in the extraction result. When true, the ocr_elements field in ExtractionResult will be populated.
min_level OcrElementLevel OcrElementLevel::Line Minimum hierarchical level to include. Elements below this level (e.g., words when min_level is Line) will be excluded.
min_confidence f64 — Minimum recognition confidence threshold (0.0-1.0). Elements with confidence below this threshold will be filtered out.
build_hierarchy bool — Whether to build hierarchical relationships between elements. When true, parent_id fields will be populated based on spatial containment. Only meaningful for Tesseract output.

LayoutRegion

A detected layout region on a page.

When layout detection is enabled, each page may have layout regions identifying different content types (text, pictures, tables, etc.) with confidence scores and spatial positions.

Field Type Default Description
class_name String — Layout class name (e.g. "picture", "table", "text", "section_header").
confidence f64 — Confidence score from the layout detection model (0.0 to 1.0).
bounding_box BoundingBox — Bounding box in document coordinate space.
area_fraction f64 — Fraction of the page area covered by this region (0.0 to 1.0).

Table

Extracted table structure.

Represents a table detected and extracted from a document (PDF, image, etc.). Tables are converted to both structured cell data and Markdown format.

Field Type Default Description
cells Vec<Vec<String>> vec![] Table cells as a 2D vector (rows × columns)
markdown String — Markdown representation of the table
page_number u32 — Page number where the table was found (1-indexed)
bounding_box Option<BoundingBox> Default::default() Bounding box of the table on the page (PDF coordinates: x0=left, y0=bottom, x1=right, y1=top). Only populated for PDF-extracted tables when position data is available.

TableCell

Individual table cell with content and optional styling.

Future extension point for rich table support with cell-level metadata.

Field Type Default Description
content String — Cell content as text
row_span u32 — Row span (number of rows this cell spans)
col_span u32 — Column span (number of columns this cell spans)
is_header bool — Whether this is a header cell

YakeParams

YAKE-specific parameters.

Field Type Default Description
window_size usize 2 Window size for co-occurrence analysis (default: 2). Controls the context window for computing co-occurrence statistics.

RakeParams

RAKE-specific parameters.

Field Type Default Description
min_word_length usize 1 Minimum word length to consider (default: 1).
max_words_per_phrase usize 3 Maximum words in a keyword phrase (default: 3).

KeywordConfig

Keyword extraction configuration.

Field Type Default Description
algorithm KeywordAlgorithm KeywordAlgorithm::Yake Algorithm to use for extraction.
max_keywords usize 10 Maximum number of keywords to extract (default: 10).
min_score f32 0 Minimum score threshold (0.0-1.0, default: 0.0). Keywords with scores below this threshold are filtered out. Note: Score ranges differ between algorithms.
ngram_range Vec<usize> vec![] N-gram range for keyword extraction (min, max). (1, 1) = unigrams only (1, 2) = unigrams and bigrams (1, 3) = unigrams, bigrams, and trigrams (default)
language Option<String> Default::default() Language code for stopword filtering (e.g., "en", "de", "fr"). If None, no stopword filtering is applied.
yake_params Option<YakeParams> None YAKE-specific tuning parameters.
rake_params Option<RakeParams> None RAKE-specific tuning parameters.

OcrCacheStats

Field Type Default Description
total_files usize — Total files
total_size_mb f64 — Total size mb

PaddleOcrConfig

Configuration for PaddleOCR backend.

Configures PaddleOCR text detection and recognition with multi-language support. Uses a builder pattern for convenient configuration.

Field Type Default Description
language String — Language code (e.g., "en", "ch", "jpn", "kor", "deu", "fra")
cache_dir Option<PathBuf> Default::default() Optional custom cache directory for model files
use_angle_cls bool — Enable angle classification for rotated text (default: false). Can misfire on short text regions, rotating crops incorrectly before recognition.
enable_table_detection bool — Enable table structure detection (default: false)
det_db_thresh f32 — Database threshold for text detection (default: 0.3) Range: 0.0-1.0, higher values require more confident detections
det_db_box_thresh f32 — Box threshold for text bounding box refinement (default: 0.5) Range: 0.0-1.0
det_db_unclip_ratio f32 — Unclip ratio for expanding text bounding boxes (default: 1.6) Controls the expansion of detected text regions
det_limit_side_len u32 — Maximum side length for detection image (default: 960) Larger images may be resized to this limit for faster inference
rec_batch_num u32 — Batch size for recognition inference (default: 6) Number of text regions to process simultaneously
padding u32 — Padding in pixels added around the image before detection (default: 10). Large values can include surrounding content like table gridlines.
drop_score f32 — Minimum recognition confidence score for text lines (default: 0.5). Text regions with recognition confidence below this threshold are discarded. Matches PaddleOCR Python's drop_score parameter. Range: 0.0-1.0
model_tier String — Model tier controlling detection/recognition model size and accuracy trade-off. - "mobile" (default): Lightweight models (~4.5MB detection, ~16.5MB recognition), fast download and inference - "server": Large, high-accuracy models (~88MB detection, ~84MB recognition), best for GPU or complex documents

Metadata Types

ExtractedImageMetadata

Image metadata extracted from an image file.

Field Type Default Description
width u32 — Image width in pixels
height u32 — Image height in pixels
format String — Image format (e.g., "PNG", "JPEG")
exif_data HashMap<String, String> — EXIF data if available

ChunkMetadata

Metadata about a chunk's position in the original document.

Field Type Default Description
byte_start usize — Byte offset where this chunk starts in the original text (UTF-8 valid boundary).
byte_end usize — Byte offset where this chunk ends in the original text (UTF-8 valid boundary).
token_count Option<usize> None Number of tokens in this chunk (if available). This is calculated by the embedding model's tokenizer if embeddings are enabled.
chunk_index usize — Zero-based index of this chunk in the document.
total_chunks usize — Total number of chunks in the document.
first_page Option<u32> None First page number this chunk spans (1-indexed). Only populated when page tracking is enabled in extraction configuration.
last_page Option<u32> None Last page number this chunk spans (1-indexed, equal to first_page for single-page chunks). Only populated when page tracking is enabled in extraction configuration.
heading_context Option<HeadingContext> /* serde(default) */ Heading context when using Markdown chunker. Contains the heading hierarchy this chunk falls under. Only populated when ChunkerType.Markdown is used.
image_indices Vec<u32> /* serde(default) */ Indices into ExtractionResult.images for images on pages covered by this chunk. Contains zero-based indices into the top-level images collection for every image whose page_number falls within [first_page, last_page]. Empty when image extraction is disabled or the chunk spans no pages with images.

ElementMetadata

Metadata for a semantic element.

Field Type Default Description
page_number Option<u32> None Page number (1-indexed)
filename Option<String> None Source filename or document name
coordinates Option<BoundingBox> None Bounding box coordinates if available
element_index Option<usize> None Position index in the element sequence
additional HashMap<String, String> — Additional custom metadata

ImagePreprocessingMetadata

Image preprocessing metadata.

Tracks the transformations applied to an image during OCR preprocessing, including DPI normalization, resizing, and resampling.

Field Type Default Description
original_dimensions Vec<usize> — Original image dimensions (width, height) in pixels
original_dpi Vec<f64> — Original image DPI (horizontal, vertical)
target_dpi i32 — Target DPI from configuration
scale_factor f64 — Scaling factor applied to the image
auto_adjusted bool — Whether DPI was auto-adjusted based on content
final_dpi i32 — Final DPI after processing
new_dimensions Vec<usize> None New dimensions after resizing (if resized)
resample_method String — Resampling algorithm used ("LANCZOS3", "CATMULLROM", etc.)
dimension_clamped bool — Whether dimensions were clamped to max_image_dimension
calculated_dpi Option<i32> None Calculated optimal DPI (if auto_adjust_dpi enabled)
skipped_resize bool — Whether resize was skipped (dimensions already optimal)
resize_error Option<String> None Error message if resize failed

Metadata

Extraction result metadata.

Contains common fields applicable to all formats, format-specific metadata via a discriminated union, and additional custom fields from postprocessors.

Field Type Default Description
title Option<String> Default::default() Document title
subject Option<String> Default::default() Document subject or description
authors Vec<String> vec![] Primary author(s) - always Vec for consistency
keywords Vec<String> vec![] Keywords/tags - always Vec for consistency
language Option<String> Default::default() Primary language (ISO 639 code)
created_at Option<String> Default::default() Creation timestamp (ISO 8601 format)
modified_at Option<String> Default::default() Last modification timestamp (ISO 8601 format)
created_by Option<String> Default::default() User who created the document
modified_by Option<String> Default::default() User who last modified the document
pages Option<PageStructure> Default::default() Page/slide/sheet structure with boundaries
format Option<FormatMetadata> Default::default() Format-specific metadata (discriminated union) Contains detailed metadata specific to the document format. Serialized as a nested "format" object with a format_type discriminator field.
image_preprocessing Option<ImagePreprocessingMetadata> Default::default() Image preprocessing metadata (when OCR preprocessing was applied)
json_schema Option<serde_json::Value> Default::default() JSON schema (for structured data extraction)
error Option<ErrorMetadata> Default::default() Error metadata (for batch operations)
extraction_duration_ms Option<u64> Default::default() Extraction duration in milliseconds (for benchmarking). This field is populated by batch extraction to provide per-file timing information. It's None for single-file extraction (which uses external timing).
category Option<String> Default::default() Document category (from frontmatter or classification).
tags Vec<String> vec![] Document tags (from frontmatter).
document_version Option<String> Default::default() Document version string (from frontmatter).
abstract_text Option<String> Default::default() Abstract or summary text (from frontmatter).
output_format Option<String> Default::default() Output format identifier (e.g., "markdown", "html", "text"). Set by the output format pipeline stage when format conversion is applied. Previously stored in metadata.additional["output_format"].
ocr_used bool — Whether OCR was used during extraction. Set to true whenever the extraction pipeline ran an OCR backend (Tesseract, PaddleOCR, VLM, etc.) and used that output as the primary or fallback text. false means native text extraction was used exclusively.
additional HashMap<String, serde_json::Value> HashMap::new() Additional custom fields from postprocessors. Serialized as a nested "additional" object (not flattened at root level). Uses Cow<'static, str> keys so static string keys avoid allocation.

ExcelMetadata

Excel/spreadsheet format metadata.

Identifies the document as a spreadsheet source via the FormatMetadata.Excel discriminant. Sheet count and sheet names are stored inside this struct.

Field Type Default Description
sheet_count Option<u32> Default::default() Number of sheets in the workbook.
sheet_names Vec<String> vec![] Names of all sheets in the workbook.

EmailMetadata

Email metadata extracted from .eml and .msg files.

Includes sender/recipient information, message ID, and attachment list.

Field Type Default Description
from_email Option<String> Default::default() Sender's email address
from_name Option<String> Default::default() Sender's display name
to_emails Vec<String> vec![] Primary recipients
cc_emails Vec<String> vec![] CC recipients
bcc_emails Vec<String> vec![] BCC recipients
message_id Option<String> Default::default() Message-ID header value
attachments Vec<String> vec![] List of attachment filenames

ArchiveMetadata

Archive (ZIP/TAR/7Z) metadata.

Extracted from compressed archive files containing file lists and size information.

Field Type Default Description
format String — Archive format ("ZIP", "TAR", "7Z", etc.)
file_count u32 — Total number of files in the archive
file_list Vec<String> vec![] List of file paths within the archive
total_size u64 — Total uncompressed size in bytes
compressed_size Option<u64> Default::default() Compressed size in bytes (if available)

ImageMetadata

Image metadata extracted from image files.

Includes dimensions, format, and EXIF data.

Field Type Default Description
width u32 — Image width in pixels
height u32 — Image height in pixels
format String — Image format (e.g., "PNG", "JPEG", "TIFF")
exif HashMap<String, String> HashMap::new() EXIF metadata tags

XmlMetadata

XML metadata extracted during XML parsing.

Provides statistics about XML document structure.

Field Type Default Description
element_count u32 — Total number of XML elements processed
unique_elements Vec<String> vec![] List of unique element tag names (sorted)

TextMetadata

Text/Markdown metadata.

Extracted from plain text and Markdown files. Includes word counts and, for Markdown, structural elements like headers and links.

Field Type Default Description
line_count u32 — Number of lines in the document
word_count u32 — Number of words
character_count u32 — Number of characters
headers Vec<String> vec![] Markdown headers (headings text only, for Markdown files)
links Vec<Vec<String>> vec![] Markdown links as (text, url) tuples (for Markdown files)
code_blocks Vec<Vec<String>> vec![] Code blocks as (language, code) tuples (for Markdown files)

HeaderMetadata

Header/heading element metadata.

Field Type Default Description
level u8 — Header level: 1 (h1) through 6 (h6)
text String — Normalized text content of the header
id Option<String> None HTML id attribute if present
depth u32 — Document tree depth at the header element
html_offset u32 — Byte offset in original HTML document

LinkMetadata

Link element metadata.

Field Type Default Description
href String — The href URL value
text String — Link text content (normalized)
title Option<String> None Optional title attribute
link_type LinkType — Link type classification
rel Vec<String> — Rel attribute values
attributes Vec<Vec<String>> — Additional attributes as key-value pairs

ImageMetadataType

Image element metadata.

Field Type Default Description
src String — Image source (URL, data URI, or SVG content)
alt Option<String> None Alternative text from alt attribute
title Option<String> None Title attribute
dimensions Vec<u32> None Image dimensions as (width, height) if available
image_type ImageType — Image type classification
attributes Vec<Vec<String>> — Additional attributes as key-value pairs

HtmlMetadata

HTML metadata extracted from HTML documents.

Includes document-level metadata, Open Graph data, Twitter Card metadata, and extracted structural elements (headers, links, images, structured data).

Field Type Default Description
title Option<String> Default::default() Document title from <title> tag
description Option<String> Default::default() Document description from <meta name="description"> tag
keywords Vec<String> vec![] Document keywords from <meta name="keywords"> tag, split on commas
author Option<String> Default::default() Document author from <meta name="author"> tag
canonical_url Option<String> Default::default() Canonical URL from <link rel="canonical"> tag
base_href Option<String> Default::default() Base URL from <base href=""> tag for resolving relative URLs
language Option<String> Default::default() Document language from lang attribute
text_direction Option<TextDirection> Default::default() Document text direction from dir attribute
open_graph HashMap<String, String> HashMap::new() Open Graph metadata (og:* properties) for social media Keys like "title", "description", "image", "url", etc.
twitter_card HashMap<String, String> HashMap::new() Twitter Card metadata (twitter:* properties) Keys like "card", "site", "creator", "title", "description", "image", etc.
meta_tags HashMap<String, String> HashMap::new() Additional meta tags not covered by specific fields Keys are meta name/property attributes, values are content
headers Vec<HeaderMetadata> vec![] Extracted header elements with hierarchy
links Vec<LinkMetadata> vec![] Extracted hyperlinks with type classification
images Vec<ImageMetadataType> vec![] Extracted images with source and dimensions
structured_data Vec<StructuredData> vec![] Extracted structured data blocks

OcrMetadata

OCR processing metadata.

Captures information about OCR processing configuration and results.

Field Type Default Description
language String — OCR language code(s) used
psm i32 — Tesseract Page Segmentation Mode (PSM)
output_format String — Output format (e.g., "text", "hocr")
table_count u32 — Number of tables detected
table_rows Option<u32> Default::default() Table rows
table_cols Option<u32> Default::default() Table cols

ErrorMetadata

Error metadata (for batch operations).

Field Type Default Description
error_type String — Error type
message String — Message

PptxMetadata

PowerPoint presentation metadata.

Extracted from PPTX files containing slide counts and presentation details.

Field Type Default Description
slide_count u32 — Total number of slides in the presentation
slide_names Vec<String> vec![] Names of slides (if available)
image_count Option<u32> Default::default() Number of embedded images
table_count Option<u32> Default::default() Number of tables

DocxMetadata

Word document metadata.

Extracted from DOCX files using shared Office Open XML metadata extraction. Integrates with office_metadata module for core/app/custom properties.

Field Type Default Description
core_properties Option<CoreProperties> Default::default() Core properties from docProps/core.xml (Dublin Core metadata) Contains title, creator, subject, keywords, dates, etc. Shared format across DOCX/PPTX/XLSX documents.
app_properties Option<DocxAppProperties> Default::default() Application properties from docProps/app.xml (Word-specific statistics) Contains word count, page count, paragraph count, editing time, etc. DOCX-specific variant of Office application properties.
custom_properties HashMap<String, serde_json::Value> HashMap::new() Custom properties from docProps/custom.xml (user-defined properties) Contains key-value pairs defined by users or applications. Values can be strings, numbers, booleans, or dates.

CsvMetadata

CSV/TSV file metadata.

Field Type Default Description
row_count u32 — Number of rows
column_count u32 — Number of columns
delimiter Option<String> Default::default() Delimiter
has_header bool — Whether header
column_types Vec<String> vec![] Column types

BibtexMetadata

BibTeX bibliography metadata.

Field Type Default Description
entry_count usize — Number of entries in the bibliography.
citation_keys Vec<String> vec![] Citation keys
authors Vec<String> vec![] Authors
year_range Option<YearRange> Default::default() Year range (year range)
entry_types HashMap<String, usize> HashMap::new() Entry types

CitationMetadata

Citation file metadata (RIS, PubMed, EndNote).

Field Type Default Description
citation_count usize — Number of citations
format Option<String> Default::default() Format
authors Vec<String> vec![] Authors
year_range Option<YearRange> Default::default() Year range (year range)
dois Vec<String> vec![] Dois
keywords Vec<String> vec![] Keywords

FictionBookMetadata

FictionBook (FB2) metadata.

Field Type Default Description
genres Vec<String> vec![] Genres
sequences Vec<String> vec![] Sequences
annotation Option<String> Default::default() Annotation

DbfMetadata

dBASE (DBF) file metadata.

Field Type Default Description
record_count usize — Number of records
field_count usize — Number of fields
fields Vec<DbfFieldInfo> vec![] Fields

JatsMetadata

JATS (Journal Article Tag Suite) metadata.

Field Type Default Description
copyright Option<String> Default::default() Copyright
license Option<String> Default::default() License
history_dates HashMap<String, String> HashMap::new() History dates
contributor_roles Vec<ContributorRole> vec![] Contributor roles

EpubMetadata

EPUB metadata (Dublin Core extensions).

Field Type Default Description
coverage Option<String> Default::default() Coverage
dc_format Option<String> Default::default() Dc format
relation Option<String> Default::default() Relation
source Option<String> Default::default() Source
dc_type Option<String> Default::default() Dc type
cover_image Option<String> Default::default() Cover image

PstMetadata

Outlook PST archive metadata.

Field Type Default Description
message_count usize — Number of messages

PdfMetadata

PDF-specific metadata.

Contains metadata fields specific to PDF documents that are not in the common Metadata structure. Common fields like title, authors, keywords, and dates are at the Metadata level.

Field Type Default Description
pdf_version Option<String> Default::default() PDF version (e.g., "1.7", "2.0")
producer Option<String> Default::default() PDF producer (application that created the PDF)
is_encrypted Option<bool> Default::default() Whether the PDF is encrypted/password-protected
width Option<i64> Default::default() First page width in points (1/72 inch)
height Option<i64> Default::default() First page height in points (1/72 inch)
page_count Option<u32> Default::default() Total number of pages in the PDF document

Document Structure

DocumentExtractor

Trait for document extractor plugins.

Implement this trait to add support for new document formats or to override built-in extraction behavior with custom logic.

Return Type

Extractors return InternalDocument, a flat intermediate representation. The pipeline converts this into the public ExtractionResult via the derivation step.

Priority System

When multiple extractors support the same MIME type, the registry selects the extractor with the highest priority value. Use this to:

  • Override built-in extractors (priority > 50)
  • Provide fallback extractors (priority < 50)
  • Implement specialized extractors for specific use cases

Default priority is 50.

Thread Safety

Extractors must be thread-safe (Send + Sync) to support concurrent extraction.

Opaque type — fields are not directly accessible.

DocumentRelationship

A resolved relationship between two nodes in the document tree.

Field Type Default Description
source u32 — Source node index (the referencing node).
target u32 — Target node index (the referenced node).
kind RelationshipKind — Semantic kind of the relationship.

DocumentNode

A single node in the document tree.

Each node has deterministic id, typed content, optional parent/children for tree structure, and metadata like page number, bounding box, and content layer.

Field Type Default Description
id String — Deterministic identifier (hash of content + position).
content NodeContent — Node content — tagged enum, type-specific data only.
parent Option<u32> None Parent node index (None = root-level node).
children Vec<u32> /* serde(default) */ Child node indices in reading order.
content_layer ContentLayer /* serde(default) */ Content layer classification.
page Option<u32> None Page number where this node starts (1-indexed).
page_end Option<u32> None Page number where this node ends (for multi-page tables/sections).
bbox Option<BoundingBox> None Bounding box in document coordinates.
annotations Vec<TextAnnotation> /* serde(default) */ Inline annotations (formatting, links) on this node's text content. Only meaningful for text-carrying nodes; empty for containers.
attributes HashMap<String, String> None Format-specific key-value attributes. Extensible bag for miscellaneous data without a dedicated typed field: CSS classes, LaTeX environment names, Excel cell formulas, slide layout names, etc.

GridCell

Individual grid cell with position and span metadata.

Field Type Default Description
content String — Cell text content.
row u32 — Zero-indexed row position.
col u32 — Zero-indexed column position.
row_span u32 /* serde(default) */ Number of rows this cell spans.
col_span u32 /* serde(default) */ Number of columns this cell spans.
is_header bool /* serde(default) */ Whether this is a header cell.
bbox Option<BoundingBox> None Bounding box for this cell (if available).

OcrTable

Table detected via OCR.

Represents a table structure recognized during OCR processing.

Field Type Default Description
cells Vec<Vec<String>> — Table cells as a 2D vector (rows × columns)
markdown String — Markdown representation of the table
page_number u32 — Page number where the table was found (1-indexed)
bounding_box Option<OcrTableBoundingBox> /* serde(default) */ Bounding box of the table in pixel coordinates (from OCR word positions).

OcrTableBoundingBox

Bounding box for an OCR-detected table in pixel coordinates.

Field Type Default Description
left u32 — Left x-coordinate (pixels)
top u32 — Top y-coordinate (pixels)
right u32 — Right x-coordinate (pixels)
bottom u32 — Bottom y-coordinate (pixels)

RecognizedTable

Pre-computed table markdown for a table detection region.

Produced by the TATR-based table structure recognizer and surfaced as part of layout-aware OCR results. The struct lives here (under layout-types, pure-Rust) so that consumers who do not enable layout-detection (ORT) can still reference the type in their own code.

Field Type Default Description
detection_bbox BBox — Detection bbox that this table corresponds to (for matching).
cells Vec<Vec<String>> — Table cells as a 2D vector (rows × columns).
markdown String — Rendered markdown table.

OCR Types

OcrPipelineStage

A single backend stage in the OCR pipeline.

Field Type Default Description
backend String — Backend name: "tesseract", "paddleocr", "easyocr", or a custom registered name.
priority u32 /* serde(default) */ Priority weight (higher = tried first). Stages are sorted by priority descending.
language Option<String> /* serde(default) */ Language override for this stage (None = use parent OcrConfig.language).
tesseract_config Option<TesseractConfig> /* serde(default) */ Tesseract-specific config override for this stage.
paddle_ocr_config Option<serde_json::Value> /* serde(default) */ PaddleOCR-specific config for this stage.
vlm_config Option<LlmConfig> /* serde(default) */ VLM config override for this pipeline stage.
backend_options Option<serde_json::Value> /* serde(default) */ Arbitrary per-call options passed through to the backend unchanged. Backends that support runtime tuning (mode switching, preprocessing flags, inference parameters, etc.) read this value and deserialize the keys they care about. Keys unknown to the backend are silently ignored, so options from different backends can coexist in the same config without conflict. Example (custom backend): json { "mode": "fast", "enable_layout": true }

OcrBackend

Trait for OCR backend plugins.

Implement this trait to add custom OCR capabilities. OCR backends can be:

  • Native Rust implementations (like Tesseract)
  • FFI bridges to Python libraries (like EasyOCR, PaddleOCR)
  • Cloud-based OCR services (Google Vision, AWS Textract, etc.)

Thread Safety

OCR backends must be thread-safe (Send + Sync) to support concurrent processing.

Opaque type — fields are not directly accessible.

OcrRotation

Rotation information for an OCR element.

Field Type Default Description
angle_degrees f64 — Rotation angle in degrees (0, 90, 180, 270 for PaddleOCR).
confidence Option<f64> None Confidence score for the rotation detection.

Other Types

BatchBytesItem

Batch item for byte array extraction.

Used with batch_extract_bytes and batch_extract_bytes_sync to represent a single item in a batch extraction job.

Field Type Default Description
content Vec<u8> — The content bytes to extract from
mime_type String — MIME type of the content (e.g., "application/pdf", "text/html")
config Option<FileExtractionConfig> None Per-item configuration overrides (None uses batch-level defaults)

BatchFileItem

Batch item for file extraction.

Used with batch_extract_files and batch_extract_files_sync to represent a single file in a batch extraction job.

Field Type Default Description
path PathBuf — Path to the file to extract from
config Option<FileExtractionConfig> None Per-file configuration overrides (None uses batch-level defaults)

SupportedFormat

A supported document format entry.

Represents a file extension and its corresponding MIME type that Kreuzberg can process.

Field Type Default Description
extension String — File extension (without leading dot), e.g., "pdf", "docx"
mime_type String — MIME type string, e.g., "application/pdf"

EmbeddingBackend

Trait for in-process embedding backend plugins.

Async to match the convention used by OcrBackend, DocumentExtractor, and PostProcessor. Host-language bridges (PyO3, napi-rs, Rustler, extendr, magnus, ext-php-rs, C FFI, etc.) wrap their synchronous host callables in spawn_blocking or the equivalent to satisfy the async signature.

Thread safety

Backends must be Send + Sync + 'static. They are stored in Arc<dyn EmbeddingBackend> and called concurrently from kreuzberg's chunking pipeline. If the backend's underlying model isn't thread-safe, the backend itself must serialize access internally (e.g. via Mutex<Inner>).

Contract

  • embed(texts) MUST return exactly texts.len() vectors, each of length self.dimensions(). The dispatcher in embed_texts validates this before returning to downstream consumers; a non-conforming backend surfaces as a KreuzbergError.Validation, not a panic.

  • embed may be called from any thread. Its future must be Send (enforced by async_trait when #[async_trait] is used on non-WASM targets).

  • dimensions() is called exactly once at registration, immediately after initialize() succeeds. The returned value is cached by the registry and used for all subsequent shape validation. Lazy-loading implementations can defer model loading into initialize() and report the real dimension afterwards. Later mutations of the backend's reported dimension are not observed by kreuzberg — implementations that need to change dimension must unregister and re-register.

  • shutdown() (inherited from Plugin) may be invoked concurrently with an in-flight embed() call. Implementations must tolerate this — e.g. by letting in-flight calls finish using resources held via the Arc<dyn EmbeddingBackend> reference, and only releasing shared state that isn't needed by embed.

Runtime

The synchronous embed_texts entry uses tokio.task.block_in_place to await the trait's async embed, which requires a multi-thread tokio runtime. Callers running inside a current_thread runtime (e.g. #[tokio.test] without flavor = "multi_thread", or tokio.runtime.Builder.new_current_thread()) must use embed_texts_async instead, which awaits directly without block_in_place.

Opaque type — fields are not directly accessible.

PostProcessor

Trait for post-processor plugins.

Post-processors transform or enrich extraction results after the initial extraction is complete. They can:

  • Clean and normalize text
  • Add metadata (language, keywords, entities)
  • Split content into chunks
  • Score quality
  • Apply custom transformations

Processing Order

Post-processors are executed in stage order:

  1. Early - Language detection, entity extraction
  2. Middle - Keyword extraction, token reduction
  3. Late - Custom hooks, final validation

Within each stage, processors are executed in registration order.

Error Handling

Post-processor errors are non-fatal by default - they're captured in metadata and execution continues. To make errors fatal, return an error from process().

Thread Safety

Post-processors must be thread-safe (Send + Sync).

Opaque type — fields are not directly accessible.

Renderer

Trait for document renderers that convert InternalDocument to output strings.

Renderers are typically stateless converters that transform the internal document representation into a specific output format (Markdown, HTML, Djot, plain text, etc.). They participate in the standard Plugin lifecycle so custom renderers can be registered from any supported binding language.

The format name is exposed via Plugin.name. For stateless renderers the Plugin lifecycle methods (version, initialize, shutdown) all take no-op defaults and need not be overridden.

Thread Safety

Renderers must be Send + Sync (inherited from Plugin).

Opaque type — fields are not directly accessible.

Plugin

Base trait that all plugins must implement.

This trait provides common functionality for plugin lifecycle management, identification, and metadata.

Thread Safety

All plugins must be Send + Sync to support concurrent usage across threads.

Opaque type — fields are not directly accessible.

Validator

Trait for validator plugins.

Validators check extraction results for quality, completeness, or correctness. Unlike post-processors, validator errors fail fast - if a validator returns an error, the extraction fails immediately.

Use Cases

  • Quality Gates: Ensure extracted content meets minimum quality standards
  • Compliance: Verify content meets regulatory requirements
  • Content Filtering: Reject documents containing unwanted content
  • Format Validation: Verify extracted content structure
  • Security Checks: Scan for malicious content

Error Handling

Validator errors are fatal - they cause the extraction to fail and bubble up to the caller. Use validators for hard requirements that must be met.

For non-fatal checks, use post-processors instead.

Thread Safety

Validators must be thread-safe (Send + Sync).

Opaque type — fields are not directly accessible.

PdfAnnotation

A PDF annotation extracted from a document page.

Field Type Default Description
annotation_type PdfAnnotationType — The type of annotation.
content Option<String> None Text content of the annotation (e.g., comment text, link URL).
page_number u32 — Page number where the annotation appears (1-indexed).
bounding_box Option<BoundingBox> None Bounding box of the annotation on the page.

DjotContent

Comprehensive Djot document structure with semantic preservation.

This type captures the full richness of Djot markup, including:

  • Block-level structures (headings, lists, blockquotes, code blocks, etc.)
  • Inline formatting (emphasis, strong, highlight, subscript, superscript, etc.)
  • Attributes (classes, IDs, key-value pairs)
  • Links, images, footnotes
  • Math expressions (inline and display)
  • Tables with full structure

Available when the djot feature is enabled.

Field Type Default Description
plain_text String — Plain text representation for backwards compatibility
blocks Vec<FormattedBlock> — Structured block-level content
metadata Metadata — Metadata from YAML frontmatter
tables Vec<Table> — Extracted tables as structured data
images Vec<DjotImage> — Extracted images with metadata
links Vec<DjotLink> — Extracted links with URLs
footnotes Vec<Footnote> — Footnote definitions
attributes Vec<String> /* serde(default) */ Attributes mapped by element identifier (if present)

FormattedBlock

Block-level element in a Djot document.

Represents structural elements like headings, paragraphs, lists, code blocks, etc.

Field Type Default Description
block_type BlockType — Type of block element
level Option<usize> None Heading level (1-6) for headings, or nesting level for lists
inline_content Vec<InlineElement> — Inline content within the block
attributes Option<String> None Element attributes (classes, IDs, key-value pairs)
language Option<String> None Language identifier for code blocks
code Option<String> None Raw code content for code blocks
children Vec<FormattedBlock> /* serde(default) */ Nested blocks for containers (blockquotes, list items, divs)

InlineElement

Inline element within a block.

Represents text with formatting, links, images, etc.

Field Type Default Description
element_type InlineType — Type of inline element
content String — Text content
attributes Option<String> None Element attributes
metadata HashMap<String, String> None Additional metadata (e.g., href for links, src/alt for images)

DjotImage

Image element in Djot.

Field Type Default Description
src String — Image source URL or path
alt String — Alternative text
title Option<String> None Optional title
attributes Option<String> None Element attributes

Link element in Djot.

Field Type Default Description
url String — Link URL
text String — Link text content
title Option<String> None Optional title
attributes Option<String> None Element attributes

Footnote

Footnote in Djot.

Field Type Default Description
label String — Footnote label
content Vec<FormattedBlock> — Footnote content blocks

TextAnnotation

Inline text annotation — byte-range based formatting and links.

Annotations reference byte offsets into the node's text content, enabling precise identification of formatted regions.

Field Type Default Description
start u32 — Start byte offset in the node's text content (inclusive).
end u32 — End byte offset in the node's text content (exclusive).
kind AnnotationKind — Annotation type.

ArchiveEntry

A single file extracted from an archive.

When archives (ZIP, TAR, 7Z, GZIP) are extracted with recursive extraction enabled, each processable file produces its own full ExtractionResult.

Field Type Default Description
path String — Archive-relative file path (e.g. "folder/document.pdf").
mime_type String — Detected MIME type of the file.
result ExtractionResult — Full extraction result for this file.

ProcessingWarning

A non-fatal warning from a processing pipeline stage.

Captures errors from optional features that don't prevent extraction but may indicate degraded results.

Field Type Default Description
source String — The pipeline stage or feature that produced this warning (e.g., "embedding", "chunking", "language_detection", "output_format").
message String — Human-readable description of what went wrong.

Chunk

A text chunk with optional embedding and metadata.

Chunks are created when chunking is enabled in ExtractionConfig. Each chunk contains the text content, optional embedding vector (if embedding generation is configured), and metadata about its position in the document.

Field Type Default Description
content String — The text content of this chunk.
chunk_type ChunkType /* serde(default) */ Semantic structural classification of this chunk. Assigned by the heuristic classifier based on content patterns and heading context. Defaults to ChunkType.Unknown when no rule matches.
embedding Vec<f32> None Optional embedding vector for this chunk. Only populated when EmbeddingConfig is provided in chunking configuration. The dimensionality depends on the chosen embedding model.
metadata ChunkMetadata — Metadata about this chunk's position and properties.

HeadingContext

Heading context for a chunk within a Markdown document.

Contains the heading hierarchy from document root to this chunk's section.

Field Type Default Description
headings Vec<HeadingLevel> — The heading hierarchy from document root to this chunk's section. Index 0 is the outermost (h1), last element is the most specific.

HeadingLevel

A single heading in the hierarchy.

Field Type Default Description
level u8 — Heading depth (1 = h1, 2 = h2, etc.)
text String — The text content of the heading.

ExtractedImage

Extracted image from a document.

Contains raw image data, metadata, and optional nested OCR results. Raw bytes allow cross-language compatibility - users can convert to PIL.Image (Python), Sharp (Node.js), or other formats as needed.

Field Type Default Description
data Vec<u8> — Raw image data (PNG, JPEG, WebP, etc. bytes). Uses bytes.Bytes for cheap cloning of large buffers.
format String — Image format (e.g., "jpeg", "png", "webp") Uses Cow<'static, str> to avoid allocation for static literals.
image_index u32 — Zero-indexed position of this image in the document/page
page_number Option<u32> None Page/slide number where image was found (1-indexed)
width Option<u32> None Image width in pixels
height Option<u32> None Image height in pixels
colorspace Option<String> None Colorspace information (e.g., "RGB", "CMYK", "Gray")
bits_per_component Option<u32> None Bits per color component (e.g., 8, 16)
is_mask bool /* serde(default) */ Whether this image is a mask image
description Option<String> None Optional description of the image
ocr_result Option<ExtractionResult> None Nested OCR extraction result (if image was OCRed) When OCR is performed on this image, the result is embedded here rather than in a separate collection, making the relationship explicit.
bounding_box Option<BoundingBox> /* serde(default) */ Bounding box of the image on the page (PDF coordinates: x0=left, y0=bottom, x1=right, y1=top). Only populated for PDF-extracted images when position data is available from the PDF extractor.
source_path Option<String> /* serde(default) */ Original source path of the image within the document archive (e.g., "media/image1.png" in DOCX). Used for rendering image references when the binary data is not extracted.
image_kind Option<ImageKind> /* serde(default) */ Heuristic classification of what this image likely depicts. None if classification was disabled or inconclusive.
kind_confidence Option<f32> /* serde(default) */ Confidence score for image_kind, in the range 0.0 to 1.0.
cluster_id Option<u32> /* serde(default) */ Identifier shared across images that form a single logical figure (e.g. all raster tiles of one technical drawing). None for singletons.

Element

Semantic element extracted from document.

Represents a logical unit of content with semantic classification, unique identifier, and metadata for tracking origin and position.

Field Type Default Description
element_id String — Unique element identifier
element_type ElementType — Semantic type of this element
text String — Text content of the element
metadata ElementMetadata — Metadata about the element

ExcelWorkbook

Excel workbook representation.

Contains all sheets from an Excel file (.xlsx, .xls, etc.) with extracted content and metadata.

Field Type Default Description
sheets Vec<ExcelSheet> — All sheets in the workbook
metadata HashMap<String, String> — Workbook-level metadata (author, creation date, etc.)

ExcelSheet

Single Excel worksheet.

Represents one sheet from an Excel workbook with its content converted to Markdown format and dimensional statistics.

Field Type Default Description
name String — Sheet name as it appears in Excel
markdown String — Sheet content converted to Markdown tables
row_count usize — Number of rows
col_count usize — Number of columns
cell_count usize — Total number of non-empty cells
table_cells Vec<Vec<String>> None Pre-extracted table cells (2D vector of cell values) Populated during markdown generation to avoid re-parsing markdown. None for empty sheets.

EmailAttachment

Email attachment representation.

Contains metadata and optionally the content of an email attachment.

Field Type Default Description
name Option<String> None Attachment name (from Content-Disposition header)
filename Option<String> None Filename of the attachment
mime_type Option<String> None MIME type of the attachment
size Option<usize> None Size in bytes
is_image bool — Whether this attachment is an image
data Option<Vec<u8>> None Attachment data (if extracted). Uses bytes.Bytes for cheap cloning of large buffers.

StructuredData

Structured data (Schema.org, microdata, RDFa) block.

Field Type Default Description
data_type StructuredDataType — Type of structured data
raw_json String — Raw JSON string representation
schema_type Option<String> None Schema type if detectable (e.g., "Article", "Event", "Product")

YearRange

Year range for bibliographic metadata.

Field Type Default Description
min Option<u32> None Min
max Option<u32> None Max
years Vec<u32> /* serde(default) */ Years

DbfFieldInfo

dBASE field information.

Field Type Default Description
name String — The name
field_type String — Field type

ContributorRole

JATS contributor with role.

Field Type Default Description
name String — The name
role Option<String> None Role

PageStructure

Unified page structure for documents.

Supports different page types (PDF pages, PPTX slides, Excel sheets) with character offset boundaries for chunk-to-page mapping.

Field Type Default Description
total_count u32 — Total number of pages/slides/sheets
unit_type PageUnitType — Type of paginated unit
boundaries Vec<PageBoundary> None Character offset boundaries for each page Maps character ranges in the extracted content to page numbers. Used for chunk page range calculation.
pages Vec<PageInfo> None Detailed per-page metadata (optional, only when needed)

PageBoundary

Byte offset boundary for a page.

Tracks where a specific page's content starts and ends in the main content string, enabling mapping from byte positions to page numbers. Offsets are guaranteed to be at valid UTF-8 character boundaries when using standard String methods (push_str, push, etc.).

Field Type Default Description
byte_start usize — Byte offset where this page starts in the content string (UTF-8 valid boundary, inclusive)
byte_end usize — Byte offset where this page ends in the content string (UTF-8 valid boundary, exclusive)
page_number u32 — Page number (1-indexed)

PageInfo

Metadata for individual page/slide/sheet.

Captures per-page information including dimensions, content counts, and visibility state (for presentations).

Field Type Default Description
number u32 — Page number (1-indexed)
title Option<String> None Page title (usually for presentations)
dimensions Vec<f64> None Dimensions in points (PDF) or pixels (images): (width, height)
image_count Option<u32> None Number of images on this page
table_count Option<u32> None Number of tables on this page
hidden Option<bool> None Whether this page is hidden (e.g., in presentations)
is_blank Option<bool> None Whether this page is blank (no meaningful text, no images, no tables) A page is considered blank if it has fewer than 3 non-whitespace characters and contains no tables or images. This is useful for filtering out empty pages in scanned documents or PDFs with blank separator pages.
has_vector_graphics bool /* serde(default) */ Whether this page contains non-trivial vector graphics (paths, shapes, curves) Indicates the presence of vector-drawn content such as charts, diagrams, or geometric shapes (e.g., from Adobe InDesign, LaTeX TikZ). These are invisible to ExtractionResult.images since they are not embedded as raster XObjects. Set to true when path count exceeds a heuristic threshold, signaling that downstream consumers may want to rasterize the page to capture this content. Only populated for PDFs; None for other document types.

PageContent

Content for a single page/slide.

When page extraction is enabled, documents are split into per-page content with associated tables and images mapped to each page.

Performance

Uses Arc-wrapped tables and images for memory efficiency:

  • Vec<Arc<Table>> enables zero-copy sharing of table data
  • Vec<Arc<ExtractedImage>> enables zero-copy sharing of image data
  • Maintains exact JSON compatibility via custom Serialize/Deserialize

This reduces memory overhead for documents with shared tables/images by avoiding redundant copies during serialization.

Field Type Default Description
page_number u32 — Page number (1-indexed)
content String — Text content for this page
tables Vec<Table> /* serde(default) */ Tables found on this page (uses Arc for memory efficiency) Serializes as Vec for JSON compatibility while maintaining Arc semantics in-memory for zero-copy sharing.
image_indices Vec<u32> /* serde(default) */ Indices into ExtractionResult.images for images found on this page. Each value is a zero-based index into the top-level images collection. Only populated when extract_images = true in the extraction config.
hierarchy Option<PageHierarchy> None Hierarchy information for the page (when hierarchy extraction is enabled) Contains text hierarchy levels (H1-H6) extracted from the page content.
is_blank Option<bool> None Whether this page is blank (no meaningful text content) Determined during extraction based on text content analysis. A page is blank if it has fewer than 3 non-whitespace characters and contains no tables or images.
layout_regions Vec<LayoutRegion> None Layout detection regions for this page (when layout detection is enabled). Contains detected layout regions with class, confidence, bounding box, and area fraction. Only populated when layout detection is configured.

PageHierarchy

Page hierarchy structure containing heading levels and block information.

Used when PDF text hierarchy extraction is enabled. Contains hierarchical blocks with heading levels (H1-H6) for semantic document structure.

Field Type Default Description
block_count u32 — Number of hierarchy blocks on this page
blocks Vec<HierarchicalBlock> /* serde(default) */ Hierarchical blocks with heading levels

HierarchicalBlock

A text block with hierarchy level assignment.

Represents a block of text with semantic heading information extracted from font size clustering and hierarchical analysis.

Field Type Default Description
text String — The text content of this block
font_size f32 — The font size of the text in this block
level String — The hierarchy level of this block (H1-H6 or Body) Levels correspond to HTML heading tags: - "h1": Top-level heading - "h2": Secondary heading - "h3": Tertiary heading - "h4": Quaternary heading - "h5": Quinary heading - "h6": Senary heading - "body": Body text (no heading level)
bbox Vec<f32> None Bounding box information for the block Contains coordinates as (left, top, right, bottom) in PDF units.

Uri

A URI extracted from a document.

Represents any link, reference, or resource pointer found during extraction. The kind field classifies the URI semantically, while label carries optional human-readable display text.

Field Type Default Description
url String — The URL or path string.
label Option<String> None Optional display text / label for the link.
page Option<u32> None Optional page number where the URI was found (1-indexed).
kind UriKind — Semantic classification of the URI.

DetectResponse

MIME type detection response.

Field Type Default Description
mime_type String — Detected MIME type
filename Option<String> None Original filename (if provided)

EmbeddingPreset

Preset configurations for common RAG use cases.

Each preset combines chunk size, overlap, and embedding model to provide an optimized configuration for specific scenarios.

All string fields are owned String for FFI compatibility — instances are safe to clone and pass across language boundaries.

Field Type Default Description
name String — The name
chunk_size usize — Chunk size
overlap usize — Overlap
model_repo String — HuggingFace repository name for the model.
pooling String — Pooling strategy: "cls" or "mean".
model_file String — Path to the ONNX model file within the repo.
dimensions usize — Dimensions
description String — Human-readable description

Keyword

Extracted keyword with metadata.

Field Type Default Description
text String — The keyword text.
score f32 — Relevance score (higher is better, algorithm-specific range).
algorithm KeywordAlgorithm — Algorithm that extracted this keyword.
positions Vec<usize> None Optional positions where keyword appears in text (character offsets).

ModelPaths

Combined paths to all models needed for OCR (backward compatibility).

Field Type Default Description
det_model PathBuf — Path to the detection model directory.
cls_model PathBuf — Path to the classification model directory.
rec_model PathBuf — Path to the recognition model directory.
dict_file PathBuf — Path to the character dictionary file.

BBox

Bounding box in original image coordinates (x1, y1) top-left, (x2, y2) bottom-right.

Field Type Default Description
x1 f32 — X1
y1 f32 — Y1
x2 f32 — X2
y2 f32 — Y2

LayoutDetection

A single layout detection result.

Field Type Default Description
class_name LayoutClass — Class name (layout class)
confidence f32 — Confidence
bbox BBox — Bbox (b box)

EmbeddedFile

Embedded file descriptor extracted from the PDF name tree.

Field Type Default Description
name String — The filename as stored in the PDF name tree.
data Vec<u8> — Raw file bytes from the embedded stream.
mime_type Option<String> None MIME type if specified in the filespec, otherwise None.

Enums

AnnotationKind

Types of inline text annotations.

Variant Wire value Description
Bold bold Bold
Italic italic Italic
Underline underline Underline
Strikethrough strikethrough Strikethrough
Code code Code
Subscript subscript Subscript
Superscript superscript Superscript
Link link Link — Fields: url: String, title: String
Highlight highlight Highlighted text (PDF highlights, HTML <mark>).
Color color Text color (CSS-compatible value, e.g. "#ff0000", "red"). — Fields: value: String
FontSize font_size Font size with units (e.g. "12pt", "1.2em", "16px"). — Fields: value: String
Custom custom Extensible annotation for format-specific styling. — Fields: name: String, value: String

BlockType

Types of block-level elements in Djot.

Variant Wire value Description
Paragraph paragraph Paragraph element
Heading heading Heading element
Blockquote blockquote Blockquote element
CodeBlock code_block Code block
ListItem list_item List item
OrderedList ordered_list Ordered list
BulletList bullet_list Bullet list
TaskList task_list Task list
DefinitionList definition_list Definition list
DefinitionTerm definition_term Definition term
DefinitionDescription definition_description Definition description
Div div Div
Section section Section element
ThematicBreak thematic_break Thematic break
RawBlock raw_block Raw block
MathDisplay math_display Math display

ChunkSizing

How chunk size is measured.

Defaults to Characters (Unicode character count). When using token-based sizing, chunks are sized by token count according to the specified tokenizer.

Token-based sizing uses HuggingFace tokenizers loaded at runtime. Any tokenizer available on HuggingFace Hub can be used, including OpenAI-compatible tokenizers (e.g., Xenova/gpt-4o, Xenova/cl100k_base).

Variant Wire value Description
Characters characters Size measured in Unicode characters (default).
Tokenizer tokenizer Size measured in tokens from a HuggingFace tokenizer. — Fields: model: String, cache_dir: PathBuf

ChunkType

Semantic structural classification of a text chunk.

Assigned by the heuristic classifier in chunking.classifier. Defaults to Unknown when no rule matches. Designed to be extended in future versions without breaking changes.

Variant Wire value Description
Heading heading Section heading or document title.
PartyList party_list Party list: names, addresses, and signatories.
Definitions definitions Definition clause ("X means…", "X shall mean…").
OperativeClause operative_clause Operative clause containing legal/contractual action verbs.
SignatureBlock signature_block Signature block with signatures, names, and dates.
Schedule schedule Schedule, annex, appendix, or exhibit section.
TableLike table_like Table-like content with aligned columns or repeated patterns.
Formula formula Mathematical formula or equation.
CodeBlock code_block Code block or preformatted content.
Image image Embedded or referenced image content.
OrgChart org_chart Organizational chart or hierarchy diagram.
Diagram diagram Diagram, figure, or visual illustration.
Unknown unknown Unclassified or mixed content.

ChunkerType

Type of text chunker to use.

Variants

  • Text - Generic text splitter, splits on whitespace and punctuation
  • Markdown - Markdown-aware splitter, preserves formatting and structure
  • Yaml - YAML-aware splitter, creates one chunk per top-level key
  • Semantic - Topic-aware chunker. With an EmbeddingConfig, splits at embedding-based topic shifts tuned by topic_threshold (default 0.75, lower = more splits). Without an embedding, falls back to a structural-boundary heuristic (ALL-CAPS headers, numbered sections, blank-line paragraphs) and merges groups into chunks capped at max_characters (default 1000). topic_threshold has no effect in the fallback path. For best results, pair with an embedding model.
Variant Wire value Description
Text text Text format
Markdown markdown Markdown format
Yaml yaml Yaml format
Semantic semantic Semantic

CodeContentMode

Content rendering mode for code extraction.

Controls how extracted code content is represented in the content field of ExtractionResult.

Variant Wire value Description
Chunks chunks Use TSLP semantic chunks as content (default).
Raw raw Use raw source code as content.
Structure structure Emit function/class headings + docstrings (no code bodies).

ContentLayer

Content layer classification for document nodes.

Replaces separate body/furniture arrays with per-node granularity.

Variant Wire value Description
Body body Main document body content.
Header header Page/section header (running header).
Footer footer Page/section footer (running footer).
Footnote footnote Footnote content.
ElementType

Semantic element type classification.

Categorizes text content into semantic units for downstream processing. Supports the element types commonly found in Unstructured documents.

Variant Wire value Description
Title title Document title
NarrativeText narrative_text Main narrative text body
Heading heading Section heading
ListItem list_item List item (bullet, numbered, etc.)
Table table Table element
Image image Image element
PageBreak page_break Page break marker
CodeBlock code_block Code block
BlockQuote block_quote Block quote
Footer footer Footer text
Header header Header text
EmbeddingModelType

Embedding model types supported by Kreuzberg.

Variant Wire value Description
Preset preset Use a preset model configuration (recommended) — Fields: name: String
Custom custom Use a custom ONNX model from HuggingFace — Fields: model_id: String, dimensions: usize
Llm llm Provider-hosted embedding model via liter-llm. Uses the model specified in the nested LlmConfig (e.g., "openai/text-embedding-3-small"). — Fields: llm: LlmConfig
Plugin plugin In-process embedding backend registered via the plugin system. The caller registers an EmbeddingBackend once (e.g. a wrapper around an already-loaded llama-cpp-python, sentence-transformers, or tuned ONNX model), then references it by name in config. Kreuzberg calls back into the registered backend during chunking and standalone embed requests — no HuggingFace download, no ONNX Runtime requirement, no HTTP sidecar. When this variant is selected, only the following EmbeddingConfig fields apply: normalize (post-call L2 normalization) and max_embed_duration_secs (dispatcher timeout). Model-loading fields (batch_size, cache_dir, show_download_progress, acceleration) are ignored — the host owns the model lifecycle. Semantic chunking falls back to ChunkingConfig.max_characters when this variant is used, since there is no preset to look a chunk-size ceiling up against — size your context window via max_characters directly. See register_embedding_backend. — Fields: name: String
ExecutionProviderType

ONNX Runtime execution provider type.

Determines which hardware backend is used for model inference. Auto (default) selects the best available provider per platform.

Variant Wire value Description
Auto auto Auto-select: CoreML on macOS, CUDA on Linux, CPU elsewhere.
Cpu cpu CPU execution provider (always available).
CoreMl coreml Apple CoreML (macOS/iOS Neural Engine + GPU).
Cuda cuda NVIDIA CUDA GPU acceleration.
TensorRt tensorrt NVIDIA TensorRT (optimized CUDA inference).
ExtractionMethod

How the extracted text was produced.

Variant Wire value Description
Native native Native
Ocr ocr Ocr
Mixed mixed Mixed
FormatMetadata

Format-specific metadata (discriminated union).

Only one format type can exist per extraction result. This provides type-safe, clean metadata without nested optionals.

Variant Wire value Description
Pdf pdf Pdf format — Fields: _0: PdfMetadata
Docx docx Docx format — Fields: _0: DocxMetadata
Excel excel Excel — Fields: _0: ExcelMetadata
Email email Email — Fields: _0: EmailMetadata
Pptx pptx Pptx format — Fields: _0: PptxMetadata
Archive archive Archive — Fields: _0: ArchiveMetadata
Image image Image element — Fields: _0: ImageMetadata
Xml xml Xml format — Fields: _0: XmlMetadata
Text text Text format — Fields: _0: TextMetadata
Html html Preserve as HTML <mark> tags — Fields: _0: HtmlMetadata
Ocr ocr Ocr — Fields: _0: OcrMetadata
Csv csv Csv format — Fields: _0: CsvMetadata
Bibtex bibtex Bibtex — Fields: _0: BibtexMetadata
Citation citation Citation — Fields: _0: CitationMetadata
FictionBook fiction_book Fiction book — Fields: _0: FictionBookMetadata
Dbf dbf Dbf — Fields: _0: DbfMetadata
Jats jats Jats — Fields: _0: JatsMetadata
Epub epub Epub format — Fields: _0: EpubMetadata
Pst pst Pst — Fields: _0: PstMetadata
Code code Code — Fields: _0: String
FracType
Variant Description
Bar Bar
NoBar No bar
Linear Linear
Skewed Skewed
HtmlTheme

Built-in HTML theme selection.

Variant Wire value Description
Default default Sensible defaults: system font stack, neutral colours, readable line measure. CSS custom properties (--kb-*) are all defined so user CSS can override individual values.
GitHub github GitHub Markdown-inspired palette and spacing.
Dark dark Dark background, light text.
Light light Minimal light theme with generous whitespace.
Unstyled unstyled No built-in stylesheet emitted. CSS custom properties are still defined on :root so user stylesheets can reference var(--kb-*) tokens.
ImageKind

Heuristic classification of what an image likely depicts.

Variant Wire value Description
Photograph photograph Photographic image (natural scene, photograph)
Diagram diagram Technical or schematic diagram
Chart chart Chart, graph, or plot
Drawing drawing Freehand or technical drawing
TextBlock text_block Text-heavy image (scanned text, document)
Decoration decoration Decorative element or border
Logo logo Logo or brand mark
Icon icon Small icon
TileFragment tile_fragment Fragment of a larger tiled image (tile of a technical drawing)
Mask mask Mask or transparency map
Unknown unknown Could not classify with reasonable confidence
ImageType

Image type classification.

Variant Wire value Description
DataUri data-uri Data URI image
InlineSvg inline-svg Inline SVG
External external External image URL
Relative relative Relative path image
InlineType

Types of inline elements in Djot.

Variant Wire value Description
Text text Text format
Strong strong Strong
Emphasis emphasis Emphasis
Highlight highlight Highlight
Subscript subscript Subscript
Superscript superscript Superscript
Insert insert Insert
Delete delete Delete
Code code Code
Link link Link
Image image Image element
Span span Span
Math math Math
RawInline raw_inline Raw inline
FootnoteRef footnote_ref Footnote ref
Symbol symbol Symbol
KeywordAlgorithm

Keyword algorithm selection.

Variant Wire value Description
Yake yake YAKE (Yet Another Keyword Extractor) - statistical approach
Rake rake RAKE (Rapid Automatic Keyword Extraction) - co-occurrence based
LayoutClass

The 17 canonical document layout classes.

All model backends (RT-DETR, YOLO, etc.) map their native class IDs to this shared set. Models with fewer classes (DocLayNet: 11, PubLayNet: 5) map to the closest equivalent.

Wire format is snake_case in all serializers (JSON, TOML, YAML).

Variant Wire value Description
Caption caption Caption element
Footnote footnote Footnote element
Formula formula Formula
ListItem list_item List item
PageFooter page_footer Page footer
PageHeader page_header Page header
Picture picture Picture
SectionHeader section_header Section header
Table table Table element
Text text Text format
Title title Title element
DocumentIndex document_index Document index
Code code Code
CheckboxSelected checkbox_selected Checkbox selected
CheckboxUnselected checkbox_unselected Checkbox unselected
Form form Form
KeyValueRegion key_value_region Key value region
LinkType

Link type classification.

Variant Wire value Description
Anchor anchor Anchor link (#section)
Internal internal Internal link (same domain)
External external External link (different domain)
Email email Email link (mailto:)
Phone phone Phone link (tel:)
Other other Other link type
ListType

Type of list detection.

Variant Description
Bullet Bullet points (-, *, •, etc.)
Numbered Numbered lists (1., 2., etc.)
Lettered Lettered lists (a., b., A., B., etc.)
Indented Indented items
NodeContent

Tagged enum for node content. Each variant carries only type-specific data.

Uses #[serde(tag = "node_type")] to avoid "type" keyword collision in Go/Java/TypeScript bindings.

Variant Wire value Description
Title title Document title. — Fields: text: String
Heading heading Section heading with level (1-6). — Fields: level: u8, text: String
Paragraph paragraph Body text paragraph. — Fields: text: String
List list List container — children are ListItem nodes. — Fields: ordered: bool
ListItem list_item Individual list item. — Fields: text: String
Table table Table with structured cell grid. — Fields: grid: TableGrid
Image image Image reference. — Fields: description: String, image_index: u32, src: String
Code code Code block. — Fields: text: String, language: String
Quote quote Block quote — container, children carry the quoted content.
Formula formula Mathematical formula / equation. — Fields: text: String
Footnote footnote Footnote reference content. — Fields: text: String
Group group Logical grouping container (section, key-value area). heading_level + heading_text capture the section heading directly rather than relying on a first-child positional convention. — Fields: label: String, heading_level: u8, heading_text: String
PageBreak page_break Page break marker.
Slide slide Presentation slide container — children are the slide's content nodes. — Fields: number: u32, title: String
DefinitionList definition_list Definition list container — children are DefinitionItem nodes.
DefinitionItem definition_item Individual definition list entry with term and definition. — Fields: term: String, definition: String
Citation citation Citation or bibliographic reference. — Fields: key: String, text: String
Admonition admonition Admonition / callout container (note, warning, tip, etc.). Children carry the admonition body content. — Fields: kind: String, title: String
RawBlock raw_block Raw block preserved verbatim from the source format. Used for content that cannot be mapped to a semantic node type (e.g. JSX in MDX, raw LaTeX in markdown, embedded HTML). — Fields: format: String, content: String
MetadataBlock metadata_block Structured metadata block (email headers, YAML frontmatter, etc.). — Fields: entries: Vec<Vec<String>>
OcrBackendType

OCR backend types.

Variant Description
Tesseract Tesseract OCR (native Rust binding)
EasyOCR EasyOCR (Python-based, via FFI)
PaddleOCR PaddleOCR (Python-based, via FFI)
Custom Custom/third-party OCR backend
OcrBoundingGeometry

Bounding geometry for an OCR element.

Supports both axis-aligned rectangles (from Tesseract) and 4-point quadrilaterals (from PaddleOCR and rotated text detection).

Variant Wire value Description
Rectangle rectangle Axis-aligned bounding box (typical for Tesseract output). — Fields: left: u32, top: u32, width: u32, height: u32
Quadrilateral quadrilateral 4-point quadrilateral for rotated/skewed text (PaddleOCR). Points are in clockwise order starting from top-left: [top_left, top_right, bottom_right, bottom_left] — Fields: points: String
OcrElementLevel

Hierarchical level of an OCR element.

Maps to Tesseract's page segmentation hierarchy and provides equivalent semantics for PaddleOCR.

Variant Wire value Description
Word word Individual word
Line line Line of text (default for PaddleOCR)
Block block Paragraph or text block
Page page Page-level element
OutputFormat

Output format for extraction results.

Controls the format of the content field in ExtractionResult. When set to Markdown, Djot, or Html, the output uses that format. Plain returns the raw extracted text. Structured returns JSON with full OCR element data including bounding boxes and confidence scores.

Variant Wire value Description
Plain plain Plain text content only (default)
Markdown markdown Markdown format
Djot djot Djot markup format
Html html HTML format
Json json JSON tree format with heading-driven sections.
Structured structured Structured JSON format with full OCR element metadata.
Custom custom Custom renderer registered via the RendererRegistry. The string is the renderer name (e.g., "docx", "latex"). — Fields: _0: String
PSMMode

Page Segmentation Mode for Tesseract OCR

Variant Description
OsdOnly Osd only
AutoOsd Auto osd
AutoOnly Auto only
Auto Auto
SingleColumn Single column
SingleBlockVertical Single block vertical
SingleBlock Single block
SingleLine Single line
SingleWord Single word
CircleWord Circle word
SingleChar Single char
PaddleLanguage

Supported languages in PaddleOCR.

Maps user-friendly language codes to paddle-ocr-rs language identifiers.

Variant Description
English English
Chinese Simplified Chinese
Japanese Japanese
Korean Korean
German German
French French
Latin Latin script (covers most European languages)
Cyrillic Cyrillic (Russian and related)
TraditionalChinese Traditional Chinese
Thai Thai
Greek Greek
EastSlavic East Slavic (Russian, Ukrainian, Belarusian)
Arabic Arabic (Arabic, Persian, Urdu)
Devanagari Devanagari (Hindi, Marathi, Sanskrit, Nepali)
Tamil Tamil
Telugu Telugu
PageUnitType

Type of paginated unit in a document.

Distinguishes between different types of "pages" (PDF pages, presentation slides, spreadsheet sheets).

Variant Wire value Description
Page page Standard document pages (PDF, DOCX, images)
Slide slide Presentation slides (PPTX, ODP)
Sheet sheet Spreadsheet sheets (XLSX, ODS)
PdfAnnotationType

Type of PDF annotation.

Variant Wire value Description
Text text Sticky note / text annotation
Highlight highlight Highlighted text region
Link link Hyperlink annotation
Stamp stamp Rubber stamp annotation
Underline underline Underline text markup
StrikeOut strike_out Strikeout text markup
Other other Any other annotation type
ProcessingStage

Processing stages for post-processors.

Post-processors are executed in stage order (Early → Middle → Late). Use stages to control the order of post-processing operations.

Variant Description
Early Early stage - foundational processing. Use for: - Language detection - Character encoding normalization - Entity extraction (NER) - Text quality scoring
Middle Middle stage - content transformation. Use for: - Keyword extraction - Token reduction - Text summarization - Semantic analysis
Late Late stage - final enrichment. Use for: - Custom user hooks - Analytics/logging - Final validation - Output formatting
ReductionLevel
Variant Description
Off Off
Light Light
Moderate Moderate
Aggressive Aggressive
Maximum Maximum
RelationshipKind

Semantic kind of a relationship between document elements.

Variant Wire value Description
FootnoteReference footnote_reference Footnote marker -> footnote definition.
CitationReference citation_reference Citation marker -> bibliography entry.
InternalLink internal_link Internal anchor link (#id) -> target heading/element.
Caption caption Caption paragraph -> figure/table it describes.
Label label Label -> labeled element (HTML <label for>, LaTeX \label{}).
TocEntry toc_entry TOC entry -> target section.
CrossReference cross_reference Cross-reference (LaTeX \ref{}, DOCX cross-reference field).
ResultFormat

Result-shape selection for extraction results.

Distinct from OutputFormat (which controls rendering — Plain, Markdown, HTML, etc.). ResultFormat controls the shape of the result: a unified content blob vs. an element-based decomposition.

Variant Wire value Description
Unified unified Unified format with all content in content field
ElementBased element_based Element-based format with semantic element extraction
StructuredDataType

Structured data type classification.

Variant Wire value Description
JsonLd json-ld JSON-LD structured data
Microdata microdata Microdata
RDFa rdfa RDFa
TableModel

Which table structure recognition model to use.

Controls the model used for table cell detection within layout-detected table regions. Wire format is snake_case in all serializers (JSON, TOML, YAML).

Variant Wire value Description
Tatr tatr TATR (Table Transformer) -- default, 30MB, DETR-based row/column detection.
SlanetWired slanet_wired SLANeXT wired variant -- 365MB, optimized for bordered tables.
SlanetWireless slanet_wireless SLANeXT wireless variant -- 365MB, optimized for borderless tables.
SlanetPlus slanet_plus SLANet-plus -- 7.78MB, lightweight general-purpose.
SlanetAuto slanet_auto Classifier-routed SLANeXT: auto-select wired/wireless per table. Uses PP-LCNet classifier (6.78MB) + both SLANeXT variants (730MB total).
Disabled disabled Disable table structure model inference entirely; use heuristic path only.
TextDirection

Text direction enumeration for HTML documents.

Variant Wire value Description
LeftToRight ltr Left-to-right text direction
RightToLeft rtl Right-to-left text direction
Auto auto Automatic text direction detection
UriKind

Semantic classification of an extracted URI.

Variant Wire value Description
Hyperlink hyperlink A clickable hyperlink (web URL, file link).
Image image An image or media resource reference.
Anchor anchor An internal anchor or cross-reference target.
Citation citation A citation or bibliographic reference (DOI, academic ref).
Reference reference A general reference (e.g. \ref{} in LaTeX, :ref: in RST).
Email email An email address (mailto: link or bare email).

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