Core features: - Class 1 T.30 protocol: full send/receive implementation - HDLC: DLE-stuffing, FCS strip, USR5637 bit-reversal handling - T.4 MH encoder/decoder (1728px A4 standard) - Document pipeline: PDF (Ghostscript), PNG, TIFF input - Width clamping: US Letter 1734px → 1728px fax standard - Cover page: CJK rasterization (TW/CN/JP/EN), TIFF + HTML output - OCR verification: Tesseract 5 with eng+chi_tra, CJK space-tolerant - API server (axum): health, send, jobs, cover, retry, cancel - Background worker: auto-poll queue, speed fallback, retry policy - Modem detection, pool management Real-world test results (2026-07-23): - V90 → 25153038: 4 pages, V.17 12000 bps, 2:33 ✅ - USR5637 → 25153038: 4 pages, V.17 12000 bps, 2:26 ✅ - Both faxes confirmed received on remote machine Tested: loopback (100% pixel match), multi-page, all input formats, cover pages, OCR verify, API endpoints, worker processing. 13 unit tests pass, 0 new clippy warnings.
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Tesseract OCR License Analysis
License Type: Apache License 2.0
✅ Yes, can use for business!
Tesseract OCR is licensed under Apache License 2.0, which is a permissive open-source license similar to MIT License.
Apache License 2.0 vs MIT License
Similarities
| Feature | Apache 2.0 | MIT | Commercial Use |
|---|---|---|---|
| Commercial use | ✅ YES | ✅ YES | ✅ Both allow |
| Modification | ✅ YES | ✅ YES | ✅ Both allow |
| Distribution | ✅ YES | ✅ YES | ✅ Both allow |
| Private use | ✅ YES | ✅ YES | ✅ Both allow |
| Sublicensing | ✅ YES | ✅ YES | ✅ Both allow |
| No royalty | ✅ YES | ✅ YES | ✅ Both allow |
Key Differences
| Feature | Apache 2.0 | MIT | Business Impact |
|---|---|---|---|
| Patent grant | ✅ Explicit patent protection | ❌ No explicit patent clause | ✅ Apache 2.0 safer for business |
| Attribution | ✅ Required | ✅ Required | ✅ Both require |
| License notice | ✅ Must keep license file | ✅ Must keep license file | ✅ Both require |
| State changes | ✅ Must document modifications | ❌ Not required | ✅ Apache 2.0 more transparent |
| Patent litigation | ✅ License terminates if you sue | ❌ No such clause | ✅ Apache 2.0 protects contributors |
| NOTICE file | ✅ Must include if present | ❌ Not required | ✅ Apache 2.0 respects attribution |
Business Usage Rights
✅ What You CAN Do
-
Commercial Use
- Use Tesseract in commercial products
- Sell products that use Tesseract
- Charge for services using Tesseract
- Use in proprietary software
-
Distribution
- Distribute Tesseract with your software
- Bundle Tesseract in your application
- Include in SaaS offerings
- Redistribute modified versions
-
Modification
- Modify source code
- Create derivative works
- Fork the project
- Add proprietary extensions
-
Integration
- Integrate into commercial systems
- Use in enterprise fax servers
- Include in paid services
- Embed in hardware products
-
Patent Protection
- Apache 2.0 grants explicit patent license
- Contributors cannot sue you for patent infringement
- Safe for commercial deployment
Requirements (Very Minimal)
✅ What You MUST Do
-
Keep License File
Include the Apache License 2.0 text -
Keep Copyright Notice
Copyright [year] Google Inc. and others Licensed under Apache License 2.0 -
Document Changes (if modified)
State significant changes to the code -
Include NOTICE File (if present)
If Tesseract has a NOTICE file, you must include it
Example Compliance
For Telfax Project
✅ Proper Compliance:
/*
* Copyright 2024 Telfax Contributors
*
* OCR processing using Tesseract OCR
*
* Tesseract OCR Copyright Google Inc. and others
* Licensed under Apache License 2.0
* http://www.apache.org/licenses/LICENSE-2.0
*
* Telfax is licensed under MIT License
*/
✅ Commercial Distribution:
# Package structure
telfax-server/
├── LICENSE # MIT License (your project)
├── THIRD-PARTY-LICENSES # Apache License 2.0 (Tesseract)
│ ├── tesseract.txt # Apache License 2.0
│ ├── leptonica.txt # (if needed)
│ └── ...
├── NOTICE # If Tesseract has one
└── README.md # Mention Tesseract usage
Comparison Summary
| License Type | Commercial Use | Patent Safety | Business Risk |
|---|---|---|---|
| Apache 2.0 | ✅ YES | ✅ High | ✅ Very Low |
| MIT | ✅ YES | ❌ Medium | ✅ Low |
| GPL | ❌ No (must open source) | ✅ High | ❌ High |
| Proprietary | ✅ YES | ❌ None | ❌ Very High |
Apache 2.0 is actually BETTER for business than MIT because:
- ✅ Explicit patent protection
- ✅ Cannot be sued for patent infringement by contributors
- ✅ Clear commercial use rights
- ✅ Widely used by major corporations (Google, Microsoft, etc.)
Real-World Examples
Companies Using Tesseract
-
Google
- Original developer of Tesseract
- Uses in Google Docs OCR
- Commercial product
-
Adobe
- Uses OCR in Acrobat
- Commercial PDF tools
- Apache 2.0 compliant
-
Microsoft
- Uses in OneNote OCR
- Commercial Office suite
- Apache 2.0 compliant
-
Small Businesses
- Document scanning services
- Invoice processing systems
- Fax server applications
- All commercially viable
Telfax Commercial Deployment
✅ Business Model Options
1. On-Premise Enterprise Fax Server
- Sell server installation
- Include Tesseract for OCR
- Apache 2.0 compliant
- ✅ ALLOWED
2. Cloud Fax Service (SaaS)
- Offer cloud fax + OCR
- Charge subscription fees
- Use Tesseract backend
- ✅ ALLOWED
3. OEM Integration
- Bundle with other products
- Sell to hardware vendors
- Include OCR feature
- ✅ ALLOWED
4. Consulting Services
- Deploy fax + OCR systems
- Charge service fees
- Custom integration
- ✅ ALLOWED
Legal Checklist
✅ Requirements for Commercial Use
- ✅ Include Apache License 2.0 text
- ✅ Keep copyright notices
- ✅ Document modifications (if any)
- ✅ Include NOTICE file (if exists)
- ✅ Don't remove existing attributions
✅ What You DON'T Need
- ❌ Don't need to pay royalties
- ❌ Don't need to open source your code
- ❌ Don't need to share modifications
- ❌ Don't need to contribute back
- ❌ Don't need special permission
Conclusion
✅ Tesseract OCR is PERFECT for Business!
Key Points:
- ✅ Apache License 2.0 allows full commercial use
- ✅ Better than MIT for business (explicit patent protection)
- ✅ Used by Fortune 500 companies (Google, Adobe, Microsoft)
- ✅ No royalties or fees required
- ✅ Can sell products using Tesseract
- ✅ Can modify and distribute commercially
- ✅ Patent safe - contributors cannot sue
Comparison with MIT:
- Apache 2.0 = MIT + Patent Protection
- Both allow commercial use
- Apache 2.0 is preferred for enterprise software
Telfax Commercial Deployment:
- ✅ Use Tesseract for OCR in fax receiver
- ✅ Sell as enterprise fax server
- ✅ Include in SaaS offering
- ✅ Bundle with hardware solutions
- ✅ All perfectly legal under Apache 2.0
References
- Tesseract OCR GitHub: https://github.com/tesseract-ocr/tesseract
- Apache License 2.0: http://www.apache.org/licenses/LICENSE-2.0
- Google Open Source Blog: https://opensource.google/
Final Answer: YES, Tesseract OCR (Apache 2.0) can be used for business, and is actually safer than MIT License for commercial deployment! ✅