Open Source Licenses Guide
Understanding open source licenses is crucial for choosing the right software for your projects. Learn about the most common licenses and what they mean for you.
Why Licenses Matter
Legal Clarity
Licenses define what you can and cannot do with the software legally.
Commercial Use
Some licenses allow commercial use, while others have restrictions.
Obligations
Understanding your obligations when using or modifying the software.
License Categories
Permissive Licenses
Allow maximum freedom with minimal restrictions. You can use, modify, and distribute the software with few obligations.
Copyleft Licenses
Require derivative works to be released under the same license, ensuring the software remains open source.
Popular Open Source Licenses
MIT License
A permissive license that allows commercial use, modification, and distribution with minimal restrictions.
Permissions
- Commercial use
- Modification
- Distribution
- Private use
Conditions
- License and copyright notice
Limitations
- Liability
- Warranty
Popular Software Using This License
GNU GPL v3
A copyleft license that requires derivative works to be open source under the same license.
Permissions
- Commercial use
- Modification
- Distribution
- Patent use
Conditions
- License and copyright notice
- State changes
- Disclose source
- Same license
Limitations
- Liability
- Warranty
Popular Software Using This License
Apache 2.0
A permissive license that provides patent protection and requires preservation of copyright notices.
Permissions
- Commercial use
- Modification
- Distribution
- Patent use
- Private use
Conditions
- License and copyright notice
- State changes
Limitations
- Liability
- Trademark use
- Warranty
Popular Software Using This License
BSD 3-Clause
A permissive license similar to MIT but with an additional clause about endorsement.
Permissions
- Commercial use
- Modification
- Distribution
- Private use
Conditions
- License and copyright notice
Limitations
- Liability
- Warranty
- Endorsement
Popular Software Using This License
GNU LGPL v3
A copyleft license that allows linking with proprietary software while keeping the library open source.
Permissions
- Commercial use
- Modification
- Distribution
- Patent use
Conditions
- License and copyright notice
- Disclose source
- Same license (library)
Limitations
- Liability
- Warranty
Popular Software Using This License
Mozilla Public License 2.0
A copyleft license that allows mixing with proprietary code while keeping MPL-licensed files open.
Permissions
- Commercial use
- Modification
- Distribution
- Patent use
- Private use
Conditions
- License and copyright notice
- Disclose source
Limitations
- Liability
- Trademark use
- Warranty
Popular Software Using This License
How to Choose the Right License
For Users
- Commercial Use: Check if the license allows commercial use if you plan to use the software in a business context.
- Modification: Consider whether you need to modify the software and what obligations that creates.
- Distribution: If you plan to distribute the software, understand your obligations.
- Compatibility: Ensure the license is compatible with other software you're using.
For Developers
- Project Goals: Choose based on whether you want to keep derivatives open source (copyleft) or allow proprietary use (permissive).
- Community: Consider what license will attract the community you want.
- Patent Protection: Some licenses provide explicit patent protection.
- Simplicity: Simpler licenses like MIT are easier to understand and comply with.
Need More Information?
For detailed legal advice about software licenses, consult with a qualified attorney. This guide provides general information only.