Kraken
Turn-key OCR system for historical and non-Latin script documents.
About
Historical documents and non-Latin scripts are the focus of Kraken, a turn key OCR system developed at the Ecole Pratique des Hautes Etudes in Paris. It provides fully trainable layout analysis, reading order detection, and character recognition, with support for right-to-left, bidirectional, and top-to-bottom writing such as Arabic and Hebrew. Recognition output comes in ALTO, PageXML, abbyyXML, and hOCR formats with word bounding boxes and character cuts. Pretrained models are shared through a public repository on Zenodo, and users can train their own segmentation and recognition models on custom material. Kraken installs via pip on Linux and macOS, including ARM machines, and pairs closely with eScriptorium, a web interface for annotating data, training models, and running transcription. Digital humanities researchers, libraries, and archives digitizing manuscripts and early printed books are its main users. Released under the Apache 2.0 license.
Should you use Kraken?
Pick it when
Pick Kraken when you digitize manuscripts or early printed books, need right-to-left or vertical scripts, want to train your own segmentation and recognition models, and need ALTO or PageXML output for an archive.
Look elsewhere when
Skip it for modern business documents or born-digital PDFs; it is built for trainable historical OCR and only Linux and macOS installs are documented. Tesseract or PaddleOCR handle everyday print with less setup.
Alternatives to Kraken
- Tesseract
Faster to start on modern print with 100+ prebuilt languages, but without Kraken's eScriptorium annotation and training workflow.
- Surya OCR
Ready-made multilingual layout and reading order from a VLM, but no archive-focused training workflow, and its weights carry a commercial-use threshold.
- PaddleOCR
Broad modern-script coverage with tables and layout out of the box, but no eScriptorium-style workflow for training on your own manuscripts.
- Chandra
Reads handwriting with a pretrained VLM and no training step, but needs an NVIDIA GPU and carries a revenue-capped weights license.
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Details
- Category
- OCR & Document Processing
- Price
- Free
- Platform
- Local/Desktop
- Difficulty
- Intermediate (3/5)
- License
- Apache-2.0
- Added
- Apr 3, 2026