sigocr

Fast PDF text extraction with paragraph layout and bounding regions.

Install

pnpm add sigocr

Usage

import { sigocr } from "sigocr";

// Extract structured text from a PDF (returns null if scanned/no embedded text)
const doc = await sigocr.pdf("/path/to/file.pdf");
// -> Document | null

// Extract from a buffer
const doc = await sigocr.buffer(pdfBuffer);

// Check if a PDF has embedded text (fast, doesn't extract)
const has = await sigocr.hasText("/path/to/file.pdf");
// -> boolean

Batch extraction

Extract many files in a single native call. Each file uses internal page-chunk parallelism via Rayon.

const docs = await sigocr.files([
  "/uploads/contract.pdf",
  "/uploads/invoice.pdf",
  "/uploads/report.pdf",
]);
// -> (Document | null)[]

Output shape

The output shape:

interface Document {
  content: string;                    // full text in reading order
  pages: Page[];
  paragraphs: Paragraph[];
  tables: Table[];
}

interface Paragraph {
  content: string;
  role?: string;                      // "title" | "sectionHeading" | "pageHeader" | "pageFooter" | "pageNumber"
  spans: Span[];                      // character offset + length into Document.content
  boundingRegions: BoundingRegion[];  // page number + polygon in points
}

Benchmarks

Measured on Apple M3 Pro, Node.js v24.

Structured extraction (with positions) - 200-page PDF

| Library | Mean | ms/page | vs sigocr | |---------|------|---------|-----------| | sigocr (native) | 16.5ms | 0.08 | 1x | | pdf.js-extract (JS) | 71.0ms | 0.36 | 4.3x slower | | pdf2json (JS) | 280ms | 1.40 | 17x slower |

Plain text extraction (no positions) - 200-page PDF

| Library | Mean | ms/page | |---------|------|---------| | pdf-parse (JS) | 51.6ms | 0.26 | | unpdf (JS) | 63.9ms | 0.32 |

Batch extraction - 100 x 3-page PDFs

| Library | Mean | vs sigocr | |---------|------|-----------| | sigocr.files (native batch) | 17.2ms | 1x | | sigocr.pdf (sequential loop) | 97.3ms | 5.7x slower | | pdf.js-extract (sequential loop) | 134.0ms | 7.8x slower |

hasText detection

| | Mean | |---|------| | sigocr hasTextBuffer | 1.7ms |

sigocr is 4.3x faster than pdf.js-extract and 17x faster than pdf2json while producing richer output: grouped paragraphs with roles, bounding regions, and document-level spans. pdf.js-extract gives raw text items that still need assembly. sigocr is also 3.1x faster than plain-text-only extractors despite doing strictly more work. Batch extraction distributes files across cores via Rayon - 100 PDFs in 17ms.

Run benchmarks yourself:

pnpm bench

How it works

• null for scanned PDFs: No OCR engine - this library only handles embedded text
• Pure Rust, no C deps: Uses pdf_oxide for character-level extraction. No PDFium/MuPDF binaries to ship. ~1 MB package
• Parallel page chunks: Large PDFs are split into chunks processed in parallel via Rayon, each opening its own PDF instance
• Paragraph roles via heuristics: Font size for heading detection, page position for header/footer/page number
• hasText() fast path: Check if a PDF has embedded text without full extraction. Checks first 3 pages only
• UTF-16 span offsets: Span offsets and lengths are in JavaScript string units for direct use with String.slice()