Explaining GPL and How Your WordPress Theme Shop Can Work Within It


WordPress is released under the GPL, and there’s some confusion over what it means, what it means to be free, and how you can run your business while upholding GPL alignment with the WordPress foundation. So, lets talk about GPL.

WordPress is released under the GPL. There is some confusion around the GPL, over what it means, what it means to be free, and how you can run your business while both upholding the law and, should you choose, upholding the spirit of the GPL in alignment with the WordPress Foundation.

What is the GPL?

The GNU General Public License (usually referred to as the GPL) is a open source license that is used for distributing software. GPL licensed software is free, as in freedom, not as in free beer. That means that users are free to distribute and modify GPL software as they please.

The GPL was created to ensure that people are not restricted by the software that they use. The GNU GPL website lists four freedoms that are protected by the GPL:

  • the freedom to use the software for any purpose
  • the freedom to change the software to suit your needs
  • the freedom to share the software with your friends and neighbors
  • the freedom to share the changes you make

Can I charge for GPL licensed products?

Absolutely. There is a common misconception that free software means no-cost software. This is not the case. Plugins and themes in the WordPress repository are free from cost, but plugins are sold by plugin shops and marketplaces, such as WPMU DEV or Code Canyon, and themes are sold by fully-GPL theme shops.

Products that are licensed under the GPL don’t have to be free from cost, the license ensures that users of that software are free to distribute and modify it. It’s worth noting that this also means that others can take your product and sell it themselves, even undercutting you should they choose.

How does the GPL work?

Upon first distribution of the software, the GPL is triggered. That means that if a WordPress user buys a theme they are then free to modify and distribute it. It’s important to note that the GPL is only triggered when the copyright holder distributes it. That means that if you do work-for-hire for a client who you sign over the copyright to, they are the copyright holder. If they choose not to distribute it then it is not available for distribution. It is not legal for someone to take that theme and distribute it. If the client decides to release the theme then the GPL is in effect. It’s also worth noting that if you don’t sign copyright of the work over to your client, that counts as distribution instead of work-for-hire and the GPL is in effect.

The GPL is a viral license. This means that any module that hooks into the original product must also be GPLed. As soon as it starts interacting with the original software the GPL is passed along.

So my plugins and themes have to be GPL?

Yes, and no. With plugins it’s a clear-cut situation. The PHP in the plugin hooks into WordPress and interacts with it. This means that plugins must be released under the GPL. With themes it’s not so simple.

The PHP interacts with WordPress and must be GPL, but the CSS, JavaScript, or design elements, do not. The WordPress Foundation believes that all themes should maintain the spirit of the GPL and release the entire theme for free, but if you released your themes with a split license you would still be following the letter of the law.

Conflicts over the GPL

Throughout WordPress’s history there have been ongoing arguments about the GPL. The most explosive one was in 2010 when WordPress co-founder Matt Mullenweg and Thesis Theme developer Chris Pearson had an explosive argument. Thesis was proprietary software, despite hooking into the GPL WordPress. After an argument on Mixergy, Pearson finally relented and Thesis went split license.

While a split license may be following the letter of the law, it’s not supported the WordPress Foundation. Companies that don’t release their products 100% GPL (i.e. using a split license) are prohibited from taking part in WordCamps whether that’s organising, sponsoring and speaking. Companies like DIY Themes (Thesis) and Envato (Theme Forest) can’t get involved with community events.

What about copyright?

When a developer creates a plugin or theme, they should include an appropriate copyright notice. Whenever someone redistributes the software they must leave the copyright notice in place. If a developer modifies the source code they have to state that they modified it and provide a date. So the plugin or theme is free for distribution and modification, but the developer still holds the original copyright.

Working within the GPL

If you’re selling WordPress themes it’s your decision whether you decide to distribute your themes 100% GPL or split license. There are only a few businesses who have held out and maintain a split license. These businesses are successful but they are often, rightly or wrongly, seen as pariahs in the WordPress community.

If you are selling themes that are 100% GPL then people who buy them from you have the right to distribute them and modify them. This forces you to do more than simply selling themes. You need to give your customers a reason to keep coming back. Here are some ways you can do it:

    • Support – excellent support is the cornerstone of a successful theme shop. People can get your theme for free, but they’re bound to have questions or need help. A support forum for paying customers is one of the best ways to keep your customers coming back.
    • Customization – you know your themes best so it makes sense for you to offer customization services. You can charge users to make customizations to craft themes to their liking.
    • Upgrades – to keep your themes secure and working with WordPress’s latest features you’ll need to release updates. You can offer automatic updates to paying users.
    • Community – theme shops like StudioPress have a strong community behind them. Users post on support forums and help each other out. Users who are just grabbing free copies of your theme won’t have any access to that.
    • Additional services – you could also explore additional services that augment your business. For example, WooThemes is diversifying into hosting. Other options are maintenance, exclusive support, and development packages.


It’s possible to run a flourishing business while still upholding the GPL. If you go for split-license you are selling a product. After all, users can distribute your PHP as they wish, but what’s a theme without its CSS? If you release fully-GPL products you are selling a service that supports your product. Many companies do this successfully, with complete success; WooThemes, StudioPress, Elegant Themes, and Headway, to name just a few.

Hopefully, after reading this, you’ll know more about what the GPL is and be able to make the right decision for your business.


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Author: Holly Bentley


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