Apache 2.0 License
The Apache 2.0 License is a standard contract that developers use to release their software for free use – including commercial purposes. It is especially widespread in the AI world because many freely available language models are published under it.
Whoever writes a program automatically owns the copyright to it. Without explicit permission, no one else may distribute or modify that program. A license is the permission that the author grants for this. The Apache 2.0 License is one such ready-made permission text, published by the Apache Software Foundation in 2004. It permits a great deal: using, modifying, distributing, and even making money with it. In return, its core requirement is only that the original author be credited and that it remains clear what has been changed in the code.
Why companies prefer this license
Free software is not always released under the same terms. Some licenses are contagious: whoever incorporates such code into their own product must also disclose their entire product. The best-known license of this kind is the GPL. The Apache 2.0 License does not do this. You may incorporate Apache code into a closed, commercial program and keep your own source code secret.
That is precisely why it is so popular with companies. Legal departments have known the text for twenty years and don’t need to review it anew each time. A start-up can take a freely available AI model, adapt it to its use case, and sell the result. No obligation arises to share one’s own work with the competition.
A second point concerns patents. A patent is a monopoly on a technical idea, independent of the concrete program text. Theoretically, someone could give away code and later sue users for patent infringement. The Apache 2.0 License rules this out: whoever contributes code automatically grants the necessary patent rights along with it. Older licenses such as MIT or BSD do not regulate this as explicitly.
What obligations the text actually imposes
The conditions are manageable. Whoever distributes Apache software must include the license text. They must leave the copyright notices in the code intact. And they must note in modified files that they have been changed. If a file named NOTICE with acknowledgments exists, its content must also be passed along.
In addition, there is a protective clause for the author. The software is provided explicitly without any warranty. If a program crashes and causes damage, the developer is not liable. This rule appears in almost all free licenses and is the price paid for giving away code free of charge.
There is also a clause against trademark misuse. The name of the project may not be used for one’s own advertising. So you may modify and sell an Apache web server, but you may not continue calling it Apache. A common misconception is that the license permits everything without exception. The attribution obligations are real obligations, and whoever ignores them loses the permission.
Apache 2.0 in the AI industry
In the news, the license appears above all in connection with so-called open AI models. Models from the French provider Mistral and parts of Alibaba's Qwen series were released under Apache 2.0. For developers, this is a strong signal: they can run the models on their own machines, without usage fees and without having to ask for permission.
The license is also ubiquitous outside of AI. The Android operating system, the programming language Kotlin, and many building blocks of large data centers are covered by it. Whoever uses any smartphone is thereby using Apache-licensed code.
One distinction is important. Not every model that can be downloaded is under Apache 2.0. Providers such as Meta use their own licenses with additional conditions, such as caps on user numbers or bans on certain uses. Such models are often still called open, but are legally more restrictive. It is therefore always worth taking a look at the license file.