WordPress is licensed under GPL — a free software license that has freedom of usage, modification, and distribution. Many developers are confused about the implications of this license but it’s not as complex as it seems.

The popularity of WordPress has to be attributed to the business model based around open-source and community contribution. A lot of open-source contributors prefer to contribute to projects that are licensed under GPL. It’s usually due to GPL’s Philosophy and idea of freedom in software being aligned with their beliefs.

First of all, some of the GPL in layman’s terms:

• Anyone may modify, use, or redistribute (provided GPL notices including license, warranty disclaimer etc. are retained) your software for free or for a price.
• Notices, including credits, in source code should be retained when re-distributing. Further credits are preferred to be added using the “modified by” or a similar notice. You are automatically the copyright holder of the code you wrote. But no credits can be forced in HTML since everyone has the right to modify the code and remove them.
• You are not required to release your code modifications to anyone. But once you distribute your modifications to anyone (a friend or anyone else), he/she has the right to distribute/release the code to public.
• If you release the code, all improved versions of the code have to be released under GPL.
• Any library/code that relies on GPL code has to be released under GPL or a GPL compatible license.

Still have questions? Head over to the official F.A.Q.

Your work for WordPress is GPL too

If there’s anything in your code that relies on WordPress’s code (template tags, functions etc.), your work automatically becomes GPL by law (derivative code), whether you state it or not. There are exceptions in both themes and plugins, however. If a few elements do not depend on the WordPress at all, they may be licensed differently – such as css files and images.

For Theme Developers

Themes do not have to be entirely GPL, as confirmed by Matt. But if you want your themes to be listed in WordPress’s directory, you’ll have to make them completely GPL or GPL compatible.

The PHP template files make extensive use of WordPress with HTML to form the layouts. Additionally, they utilize WordPress’s theme engine. CSS and image files are an exception since they do not rely on anything in WordPress at all.

Given that being listed in wordpress.org isn’t a requirement, you can license your theme’s PHP files using GPL but use a proprietary/custom license for the images and CSS.

For Plugin Developers

Practically, all your plugins have to be GPL as they’re derived work. People have debated tirelessly over the issue but as explained in the faq, all your plug-ins have to be licensed using GPL or a compatible license.

The only exception is when you create a completely isolated software that’s bridged to WordPress but uses no API functions (except for a few ‘action’ hooks to initialize the software) or data structures. One example of such would be an isolated photo gallery which is associated with a certain action hook to be displayed at one specific page.

Retaining control and limiting competition

One of the philosophies of GNU GPL is that of freedom. Anyone should have the right to do whatever they want with your software which includes re-distributing your software for a fee. While as absurd as it may sound to the business-minded people stuck with a tunnel vision or a different school of thought, it is the driving force behind the success of WordPress and many other open-source softwares out there.

Having WordPress open-source has resulted in immense contributions and development. That’s exactly what made it so usable for hundreds of thousands of people who use WordPress on daily basis, without paying a penny! It’s also helped setup many small businesses that rely on WordPress. Matt has written an awesome article, price of freedom, explaining the same in detail.

Think outside the box
Cliche, you may say (I’m guilty!). But if you want to earn money from WordPress, learning from Automattic’s success is a good idea. I prefer to think of business opportunities in an innovative style. Offering support, customizations, a SaaS with freemium model etc.

Your competition is not strong enough
Even if somebody decides to take a free-ride on your code, they’ll not know the system and code as good as you do and as such their support will be lackluster. And though it may be legal, it’s considered unethical by most, so a large brand is almost never likely to go that route; in other words, your competition – if any – will be small.

Moreover, without a better execution (improvements) on your competition’s part, you’ll have nothing to worry about. Alister has a good article on creating value and why GPL is not the problem.

Brand Matters and First Mover Advantage
Everyone knows about branding. And brand matters. Business theories, when considering free/cheap me-toos, suggest that they’re often considered inferior alternatives in the mind of consumers. Additionally, first-mover advantage will be in your favor too.

Combine both brand, quality and first mover’s advantage (support, improvements etc.) and you will have almost all of the market.

Isolate it, or license certain elements differently
Isolation is one idea that’s not very practical as discussed in plugins section. But licensing differently is one option for theme developers as discussed earlier.

Good Luck and Keep In Touch!

Licensing issues with WordPress are exaggerated. A business around WordPress still has immense potential given you do it right. So don’t let the naysayers put you off. Your thoughts? Ideas? I would love to hear them. Please leave a comment.

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