PDF OCR server
Document Engine includes optical character recognition (OCR) capabilities to accurately recognize text and patterns, as well as generate searchable PDF/A files. As of Document Engine 1.16.0, GdPicture OCR is the recommended engine and is used by default when available, while Core OCR is deprecated and will be removed in a future release. The x-pspdfkit-ocr-engine request header and the OCR_ENGINE=core configuration value are also deprecated, and no replacement OCR engine selector will be added.
Looking for more advanced OCR capabilities? Nutrient .NET SDK OCR offers additional powerful features, such as zonal OCR, key-value extraction, image preprocessing, searchable PDF/A generation with layout retention, orientation detection, confidence scoring, and more. It’s available as a separate SDK and can be used in conjunction with Document Engine.
Read more →Comparing OCR SDKs: Nutrient vs. Apryse
| Feature | Document Engine OCR | Nutrient .NET SDK OCR | Apryse OCR |
|---|---|---|---|
| Multi-language support | 120+ built-in languages | 30+ built-in languages | Six built-in languages with OCR module binary and 10 with IRIS OCR module |
| Searchable PDF creation | ✅ | ✅ | ✅ |
| OCR with exact bounding box coordinates | ❌ | ✅ | ✅ |
| Zone-based OCR/custom OCR regions | ❌ | ✅ | ✅ |
| Key-value/table extraction | ✅ (available through the Data Extraction API) | ✅ | ❌ |
| Orientation detection | ❌ | ✅ | ✅ |
| Image preprocessing (deskew, etc.) | ❌ | ✅ | ✅ (manual) |
| Performance and speed | ✅ Fast | ✅ Fast | Depends on SDK setup (OCR module/IRIS module) |
| API access | Simple HTTP API | Requires SDK setup | Requires SDK setup |
Real-world use cases
- Invoice OCR — Convert scanned invoices into searchable PDFs, or extract totals and vendor info using OCR.
- Contract digitization — Turn scanned contracts into searchable, selectable PDFs for legal archiving.
- Form processing — Use OCR to extract fields like names, dates, and signatures from scanned forms.
- Multi-language document digitization — OCR documents in multiple languages with full Unicode support.
Which OCR SDK should I use?
| Need | SDK to use |
|---|---|
| Basic OCR from PDFs/images | Document Engine OCR |
| Production-ready OCR solution without SDK setup | Document Engine OCR |
| OCR with form data, zones, orientation detection | Nutrient .NET SDK OCR |
| Batch processing of scanned documents | Either, depending on volume |
| Need to preserve layout, tables | Prefer Nutrient .NET SDK OCR |
Guides for OCR
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