WordPress plugin licensing is a topic that confuses many developers. WordPress itself is licensed under GPLv2, and the official plugin directory requires all hosted plugins to be GPL-compatible. But the world of commercial plugin licensing is more nuanced, and misunderstanding the rules can lead to legal trouble.
This guide covers what every WordPress plugin developer needs to know about licensing, from GPL compliance to commercial licensing models.
The GPL and WordPress
The GNU General Public License (GPL) is the license that WordPress itself uses. It grants users the freedom to run, study, share, and modify the software. Any derivative work — code that’s based on WordPress code — must also be licensed under GPL. This is why plugins on the WordPress.org directory must be GPL-compatible.
The GPL allows commercial use. You can sell GPL-licensed software for any price. The GPL requires that anyone who receives the software also receives the right to redistribute it, which means a customer who buys your plugin can give it away for free. This creates tension with traditional software business models.
Dual Licensing: GPL + Commercial
Most successful WordPress plugin businesses use a dual licensing model. The free version on WordPress.org is GPL. The premium version uses a commercial license that restricts redistribution and requires annual payment for updates and support. This approach is accepted by the WordPress community and is used by most major plugin companies.
Your plugin’s license should be clearly stated in the plugin header, README, and on your website. Use the standard WordPress license header for the free version. For the premium version, use a commercial license that grants the customer a non-transferable right to use the plugin on their sites.
Trademark Protection
A trademark protects your brand name and logo, independent of copyright and licensing. Registering your plugin’s name as a trademark prevents others from selling plugins under the same name. Unlike copyright, trademark protection isn’t automatic — you must register it and enforce it.
Trademark registration is particularly important for plugin businesses. If your plugin becomes popular, others may try to capitalize on your brand by releasing plugins with similar names. A registered trademark gives you legal grounds to stop this.
Common Licensing Mistakes
Including GPL code in a plugin without disclosing it violates the license. If you incorporate GPL-licensed code into your plugin — including code from the WordPress core or other GPL plugins — your plugin must be GPL-compatible too.
Claiming that GPL-licensed code can’t be used commercially is incorrect. The GPL explicitly allows commercial use. Confusing copyright with trademark is another common mistake — copyright protects your code, trademark protects your brand, and they’re enforced differently. Ignoring international copyright laws can also cause issues — the GPL applies globally, not just in the United States.
Protecting Your Work
Plugin code itself can’t be fully protected from copying under the GPL. Your competitive advantage comes from service, support, frequent updates, and brand reputation — not from preventing people from using your code. The plugin businesses that thrive are those that embrace this reality and build their value proposition around things that can’t be copied: quality, support, and community.
Protect what can be protected. Register your trademarks. Use a commercial license for premium features. Build a brand that customers trust. And focus your energy on making your plugin so good that people want to pay for it, rather than trying to prevent them from using it without paying.
The Bottom Line
WordPress plugin licensing isn’t as complicated as it seems. The free version is GPL (required by the WordPress directory). The premium version can have a commercial license with restrictions on redistribution and requirements for annual payment. Protect your brand with trademarks, not copyright. And build a business model based on service, support, and quality — not on trying to circumvent the GPL.