What is the GPL? How it works legally

Learn what you can do, what you must include, and how redistribution, updates, trademarks, and safety work.
GPLUno Guides

What is the GPL for WordPress? How it works legally

If you build or run WordPress sites, the GPL is the license that makes the ecosystem work. This guide explains what the GPL allows, what it requires, how it applies to WordPress plugins and themes, and how redistribution and updates fit in.

Last updated September 7, 2025 · Not legal advice

TL;DR The GNU General Public License gives you four freedoms for WordPress code: use, study, modify, and share. In practice, WordPress plugins and themes that link to core are GPL-compatible. You can redistribute and even sell GPL code if you keep the license and source available. Trademarks, brand names, and access to original update servers are separate from GPL rights.

1) GPL in plain language

The GNU General Public License is a copyleft license that guarantees four key freedoms for software users:

Freedom 0 - You may use the software for any purpose.
Freedom 1 - You may study how it works and view the source code.
Freedom 2 - You may modify the code to suit your needs.
Freedom 3 - You may share copies, modified or unmodified, under the same license.

Copyleft means that if you distribute a modified version, you must keep it under the GPL and provide the source code to those you distribute it to. The GPL does not require you to provide free support, hosting, or automatic updates.

2) How the GPL fits WordPress

WordPress core is licensed under GPL version 2 or later. Themes and plugins interact with WordPress through its APIs. In the WordPress community, code that links to core is considered a derivative work and must be GPL-compatible when distributed.

ComponentTypical licensing reality
Plugin PHP that uses WordPress APIsGPL-compatible
Theme PHP that uses WordPress APIsGPL-compatible
Non-code assets like stock photos, icons, fontsMay use other licenses. Check each asset.
Brand names and logosProtected by trademark law, separate from GPL.
Access to developer update serversContractual service, not granted by the GPL.

Minified or compiled distributions are still covered by the GPL. If you distribute them, you must make the human-readable source available to your recipients on request.

3) What you can do under the GPL

  • Use any GPL WordPress plugin or theme on unlimited sites, including commercial projects.
  • Study the code, learn from it, and adapt it to your needs.
  • Modify the code and keep those changes private if you do not distribute a copy.
  • Redistribute original or modified GPL code, including for a fee, as long as you keep the GPL license and provide source to your recipients.
  • Bundle GPL plugins with a client project. You may set your own price for your service.
  • Offer your own update channel or mirrors for GPL code you distribute.

4) What you cannot do or must not imply

  • Do not remove or falsify copyright and license notices in the source.
  • Do not imply you are the original author or official vendor if you are not.
  • Do not use another company’s trademarks or logos in a way that confuses users.
  • Do not promise access to the original developer’s update servers or license keys unless you actually provide them.
  • Do not mix in non-GPL assets that forbid redistribution without checking their licenses first.
Tip: If you redistribute, include the GPL text, the original license headers, and a clear changelog. Offer a way for recipients to get the source code.

5) Trademarks, branding, and update servers

The GPL covers code rights. Trademarks cover brand names and logos. Update servers and license keys are services controlled by the vendor. You can legally redistribute GPL code, but that does not grant you the vendor’s trademark usage or their private update service.

If you are a distributor, be clear about what you provide: original files, your own update mechanism, documentation, and the GPL license text. Avoid language that suggests you are the official brand unless you are authorized.

6) GPL vs “nulled” downloads

People use the word “nulled” for random downloads on the internet. The GPL does allow redistribution. The risk is not the license but the source. Nulled sites often inject malware, remove security checks, or ship outdated code.

  • Verify integrity with hashes like SHA256 and compare across mirrors when possible.
  • Scan zips before uploading. Keep staging environments and file change monitoring.
  • Prefer reputable distributors who show version history and clearly post license notices.

7) Are premium plugins still GPL

Premium plugins and themes can charge for access, support, and services. The PHP that links to WordPress is GPL-compatible when distributed. Non-code assets may have different licenses. Always check the package for a LICENSE or readme that explains asset licensing.

8) Compliance checklist

For site owners

  • Keep copies of license files and changelogs.
  • Use trusted sources and verify file hashes.
  • Stage updates, then push to production.
  • Document any custom changes you make.

For distributors

  • Include the GPL license text and preserve copyright headers.
  • Offer source code on request if you ship minified builds.
  • Publish a clear changelog and last updated date.
  • Explain that trademarks and official update servers are not included unless stated.
  • Scan releases and publish checksums like SHA256.
RightObligation
Redistribute or sell copiesKeep GPL intact, provide source to your recipients
Modify codeShare source with those you distribute your modified copy to
Charge for access or servicesDo not claim official affiliation if you are not authorized
Bundle with projectsPreserve license and notices in deliverables

9) Quick FAQ

Is it legal to resell GPL WordPress plugins and themes
Yes. You must keep the GPL license, preserve copyright notices, and provide source code to your recipients. Trademarks and vendor services are separate.
Do I get automatic updates if I buy from a distributor
Only if the distributor provides their own update channel. Access to the original developer’s servers is not granted by the GPL.
Do I have to publish my custom changes
No, unless you distribute your modified copy. If you only use it privately, you are not required to release anything.
What about non-code assets like icons and fonts
They can carry their own licenses. Check the package and respect any attribution or redistribution rules for those assets.
Does GPL mean free of charge
No. Free refers to freedom, not price. You can charge for distribution, hosting, updates, and support.

10) How GPLUno operates

We respect the GPL and the WordPress community:

  • We preserve original license notices and include the GPL text.
  • We verify and scan files before publishing. We publish version and updated date.
  • We provide our own documentation and delivery. Access to original vendors’ private update servers is not promised.
  • We avoid confusing trademark usage and always state when a product name is a trademark of its owner.

11) Disclaimer

This article is general information, not legal advice. If you need specific guidance for your jurisdiction or business model, talk to a qualified attorney.

© GPLUno. “WordPress” and related trademarks are owned by the WordPress Foundation and are used for descriptive purposes only.
  • Published
    7 September 2025
  • Page views
    160
Back
Top