Licensing

• Software is automatically protected by copyright: Others cannot reuse your code without explicit permission.
• A license grants that permission and defines boundaries, conditions, and responsibilities.
• Licensing is essential for:
  • Reproducibility: others must be able to run and inspect your code.
  • Collaboration: colleagues need clarity on what they may do.
  • Open Science: journals and funders increasingly require a clear license.
  • Protecting yourself: licenses limit liability and ensure attribution.

Without a license, your code is not legally reusable, even if it is public on GitHub.

Choosing a license at the start of your project:

• Sets expectations for collaborators.
• Prevents incompatible contributions (e.g., GPL vs. MIT).
• Avoids legal or administrative issues later.
• Ensures compliance with institutional or funder requirements.
• Saves you from needing to re‑contact contributors later.

Early licensing is part of good research hygiene like documentation, folder structure, and version control.

• There are over 80 OSI-approved licenses
  (and many, many others).

Utrecht University recommends the MIT License:

What is important to you?
What does your lab use?

Try a license selector:
https://ufal.github.io/public-license-selector/

• Permissive licenses (MIT, BSD, Apache 2.0)
  Few restrictions; widely used in research.

• Copyleft licenses (GPL, AGPL, LGPL)
  Derivative works must use the same license.

• Restrictive / proprietary licenses
  Limit reuse and redistribution.

Explore options via:
https://choosealicense.com

Changing a license is possible, but requires care:

• Copyright ownership
  You must obtain permission from all contributors unless a CLA is in place.

• Dependency compatibility
  Some licenses cannot be mixed (e.g., GPL code cannot be relicensed as MIT).

• Downstream users
  Past versions remain under the old license; the new license applies only to future releases.

• Institutional or funder requirements
  Some projects must use specific licenses.

If you change your license:

• Update LICENSE.md
• Update README.md
• Document the change in release notes or CHANGELOG

• There are different licenses for software and data.
• Separate code and software publications from data publications.
• Link software and data through their DOIs.
• Provide clear instructions in your README:
  • how to obtain the data
    
  • how to run the software on the published dataset

For more detail:
https://book.the-turing-way.org/reproducible-research/licensing/licensing-data/

Software and data serve different purposes and therefore require different types of licenses:

Key differences:

• Software licenses govern functional artifacts (code that executes).
  
• Data licenses govern informational artifacts (facts, measurements, text, images).
  
• Software licenses may require derivative works to adopt the same license
• Data may contain sensitive or personal information, requiring additional restrictions.