What happens if I use a GPL-3.0 library in my proprietary application?

GPL-3.0 is a strong copyleft license. If you compile or link GPL-3.0 code into your application and distribute the binaries to customers, the GPL mandates that your entire software application must be released under GPL-3.0 with complete source code made public.

What is the AGPL-3.0 "SaaS Loophole" clause?

Standard GPL only triggers source code disclosure upon distribution of binaries. AGPL-3.0 (Affero GPL) closes this loophole: if your software runs as a web service over a network, every user who interacts with your SaaS is legally entitled to download the entire underlying source code.

How does LGPL differ from standard GPL for proprietary apps?

LGPL (Lesser GPL) is a weak copyleft license designed for libraries. If you link dynamically (such that an end user can replace the LGPL library with a modified version), your application code remains proprietary and closed-source.

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Open Source License Compatibility Checker

Analyze compatibility between 11 major open-source licenses (MIT, Apache, GPL, LGPL, AGPL, BSD, MPL) and proprietary SaaS architectures.

Quick Common Founder Scenarios:

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Step 2

Third-Party Dependency License

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Compatibility Verdict & Legal Obligations

Deterministic OSI & FSF compatibility matrix verification

Select Both Licenses AboveChoose your project license and the dependency license (or click a quick preset) to inspect compatibility and obligations.

How to Check License Compatibility

Audit your third-party packages against your startup distribution license in 3 steps.

1. Select Your Project License

Choose how you distribute your software (e.g. Proprietary / Closed Source Commercial, MIT, or Apache-2.0).

2. Select the Third-Party Dependency License

Select the license of the library you are evaluating (e.g. GPL-3.0, LGPL-2.1, AGPL-3.0, or MPL-2.0).

3. Review the Compatibility Verdict & Legal Obligations

Instantly review whether the combination is Compatible, Conditionally Permitted, or Incompatible, along with specific attribution and disclosure requirements.

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Frequently Asked Questions

Yes. Both MIT and Apache 2.0 are permissive open-source licenses. They permit commercial use, modification, and bundling inside closed-source proprietary software provided you include the original author copyright notice and license text in your product documentation.

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Deterministic Legal MatrixDeveloper Tools

Open Source License Compatibility Checker

Analyze compatibility between 11 major open-source licenses (MIT, Apache, GPL, LGPL, AGPL, BSD, MPL) and proprietary SaaS architectures.

Quick Common Founder Scenarios:

Step 1

Your Project License

Select Your Distribution License

Step 2

Third-Party Dependency License

Select Library / Package License

Compatibility Verdict & Legal Obligations

Deterministic OSI & FSF compatibility matrix verification

Select Both Licenses AboveChoose your project license and the dependency license (or click a quick preset) to inspect compatibility and obligations.

How to Check License Compatibility

Audit your third-party packages against your startup distribution license in 3 steps.

1. Select Your Project License

Choose how you distribute your software (e.g. Proprietary / Closed Source Commercial, MIT, or Apache-2.0).

2. Select the Third-Party Dependency License

Select the license of the library you are evaluating (e.g. GPL-3.0, LGPL-2.1, AGPL-3.0, or MPL-2.0).

3. Review the Compatibility Verdict & Legal Obligations

Instantly review whether the combination is Compatible, Conditionally Permitted, or Incompatible, along with specific attribution and disclosure requirements.

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