pdf-inspector
Fast Rust library for PDF classification and text extraction. Detects whether a PDF is text-based or scanned, extracts text with position awareness, and converts to clean Markdown — all without OCR. Includes bindings for Python, Node.js, and browser WebAssembly.
Built by Firecrawl to handle text-based PDFs locally in under 200ms, skipping expensive OCR services for the ~54% of PDFs that don't need them.
Features
- Smart classification — Detect TextBased, Scanned, ImageBased, or Mixed PDFs in ~10-50ms by sampling content streams. Returns a confidence score (0.0-1.0) and per-page OCR routing.
- Text extraction — Position-aware extraction with font info, X/Y coordinates, and automatic multi-column reading order.
- Markdown conversion — Headings (H1-H4 via font size ratios), bullet/numbered/letter lists, code blocks (monospace font detection), tables (rectangle-based and heuristic), bold/italic formatting, URL linking, and page breaks.
- Table detection — Dual-mode: rectangle-based detection from PDF drawing ops, plus heuristic detection from text alignment. Handles financial tables, footnotes, and continuation tables across pages.
- CID font support — ToUnicode CMap decoding for Type0/Identity-H fonts, UTF-16BE, UTF-8, and Latin-1 encodings.
- Multi-column layout — Automatic detection of newspaper-style columns, sequential reading order, and RTL text support.
- Encoding issue detection — Automatically flags broken font encodings so callers can fall back to OCR.
- Single document load — The document is parsed once and shared between detection and extraction, avoiding redundant I/O.
- Browser WebAssembly — Run the same Rust parser locally in browsers and Web Workers, with embedded CMaps and no server round trip.
- Lightweight — Pure Rust, no ML models, no external services. Single dependency on
lopdffor PDF parsing.
Benchmark
Evaluated on the opendataloader-bench corpus (200 PDFs). Only local engines without model-based PDF parsing are shown; OCR was disabled. Scores are 0-1, higher is better.
| Engine | Overall | Reading Order (NID) | Tables (TEDS) | Headings (MHS) | Speed (200 docs) |
|---|---|---|---|---|---|
| pdf-inspector | 0.875 | 0.915 | 0.814 | 0.788 | 2.8s |
| liteparse | 0.870 | 0.908 | 0.693 | 0.811 | 13.9s |
| opendataloader | 0.843 | 0.912 | 0.489 | 0.760 | 9.8s |
| pymupdf4llm | 0.735 | 0.886 | 0.401 | 0.424 | 15.5s |
| markitdown | 0.583 | 0.879 | 0.000 | 0.000 | 6.7s |
Results were refreshed on July 16, 2026, on an Apple M4 Pro. Engine versions were pdf-inspector 0.1.6, LiteParse 2.6.0, OpenDataLoader 2.1.1, PyMuPDF4LLM 0.2.0, and MarkItDown 0.1.4. Speed is the median of three complete corpus runs.
For context, engines that use OCR or model-based document parsing (docling, marker, mineru) score 0.83-0.88 overall but take 2-180 minutes on the same corpus — pdf-inspector reaches the top of that range without either, in 2.8 seconds.
Best fit: Native-text PDFs where speed, reading order, and table structure matter. pdf-inspector delivered the highest overall, reading-order, and table scores, along with the fastest complete run in this benchmark. That makes it a strong local default for reports, research papers, financial documents, invoices, and legal PDFs that need clean, structured Markdown without adding OCR latency or infrastructure.
Use the [paired benchmark harness](docs/