What an MIT License Means for Software You Use

The MIT License is one of the shortest and most permissive open-source licenses

An MIT License is a legal agreement that lets you use, modify, and share software with almost no restrictions. The person or company that wrote the software keeps their name on it, but they give up the right to control what you do with it. You can use it in your own projects, sell software that includes it, change the code, or give it away — as long as you keep a copy of the original license and the author's name attached.

The license is named after the Massachusetts Institute of Technology, which created it in the 1980s. It became popular because it is short (about 170 words), straightforward to understand, and does not require you to share your own code back. If you read software with an MIT License, you are not forced to open-source your own work or pay anyone money.

Key Takeaways

MIT License software can be used, modified, and sold with almost no restrictions, as long as you keep the original license and author attribution.
You do not have to share your own code or pay fees when you use MIT-licensed software, even in commercial products.
The original author keeps no control over how the software is used and cannot be held responsible if it breaks or causes harm.
You must include a copy of the MIT License text and the original author's name in any version you distribute, whether you changed it or not.

What you can and cannot do with MIT-licensed software

You can use MIT-licensed code in almost any way you want. You can include it in a closed-source product you sell, modify it to fit your needs, combine it with other software, or use it as the foundation for something completely new. You can also give it away, publish it, or keep it private. None of these actions violate the license.

The only real requirement is that you keep the license text and the author's name visible. If you distribute the software — whether you sell it, give it away, or publish it online — you must include a copy of the MIT License and credit the original author. If you modify the code, you should note what you changed, though the license does not strictly require it. The license does not require you to release your own code, pay royalties, or ask permission before using the software.

Why authors choose the MIT License

Developers and companies use the MIT License when they want their work to be useful to as many people as possible without legal complications. It removes barriers to adoption. A programmer who releases code under MIT knows that a business can use it in a product without worrying about being forced to open-source their entire process. This makes MIT-licensed software attractive to companies that might otherwise avoid open-source code.

The license also protects the author. By including the MIT License, the original creator makes clear that they are not responsible if the software breaks, causes data loss, or creates security problems. This legal protection is important because software always has bugs and limitations. The author is saying: "You can use this, but I make no promises about what it will do."

MIT License versus other common licenses

The MIT License is more permissive than some open-source licenses but less strict than others. The GPL (General Public License), for example, requires that any software built on top of GPL code must also be open-source. If you use GPL code in your project, you must release your own code publicly. MIT has no such requirement — you can keep your work private.

The Apache License 2.0 is similar to MIT but includes extra language about patents and how to handle modifications. The BSD License (Berkeley Software Distribution) is nearly identical to MIT and just as permissive. If you see software labeled "public domain," it means the author gave up all rights entirely, which is even more open than MIT. In practice, MIT, BSD, and Apache are all considered "permissive" licenses that let you do almost anything, while GPL is "copyleft" because it requires you to share changes back.

What to do when you use MIT-licensed software

If you use MIT-licensed code in your own project, keep a copy of the license file in your code repository or project folder. Most MIT-licensed projects include a file called LICENSE or LICENSE.txt in the root directory. Copy that file into your own project. If you are combining code from multiple MIT-licensed sources, you may need to include multiple license files or create a single file that lists all the authors and their original licenses.

If you are distributing software that includes MIT-licensed code — whether you sell it, publish it online, or give it to someone else — include the license and author attribution in your documentation, a README file, or an "About" section. For example, if you use an MIT-licensed library in a web process, you might list it in a credits page or in the source code comments. The exact format does not matter as long as the information is there and straightforward to find.

How to find the MIT License text

The MIT License text is standardized and short. You can find the exact wording on opensource.org, which is maintained by the Open Source Initiative, a nonprofit that reviews and approves open-source licenses. You can also find it on choosealicense.com, a site created by GitHub that helps developers pick the right license for their projects. Both sites let you copy the license text directly.

When you read open-source software from GitHub, GitLab, or other code repositories, the license is usually included in a file at the top level of the project. If you are unsure whether software is MIT-licensed, look for a LICENSE file or check the README. Most projects state their license clearly in the first few lines of the README or on the project's main page.

Frequently Asked Questions

Can I use MIT-licensed software in a product I sell?

Yes. You can use MIT-licensed code in commercial software without paying fees or releasing your own code. You only need to include the original license and author attribution in your product or documentation.

Do I have to share my changes if I modify MIT-licensed code?

No. You can modify MIT-licensed software and keep your changes private. You do not have to contribute your improvements back to the original project. However, if you distribute your modified version, you still need to include the original license and author credit.

What happens if MIT-licensed software breaks my process?

The MIT License includes a disclaimer that the software is provided "as is" with no warranty. The author is not responsible for bugs, security problems, or damage caused by the software. You use it at your own risk and are responsible for testing it before relying on it.

Can the original author take back an MIT License?

Once software is released under the MIT License, the license cannot be revoked for code that was already distributed. However, the author can change the license for future versions of the software. Code you downloaded under MIT stays under MIT.

Is MIT-licensed software really free to use?

Yes, MIT-licensed software is free to use, modify, and distribute. There are no licensing fees, royalties, or subscription costs. The only cost is your time to understand and integrate the code into your project.

This guide is for general information only and is not medical, financial, legal, or other professional advice. For decisions specific to your situation, consult a qualified professional. See our Editorial Policy.