The MIT License is the shortest and most permissive open-source license

The MIT License is a legal agreement that lets you use, modify, and share software with almost no restrictions. It is one of the most common licenses you will encounter because it places almost no limits on what you can do — you can use the software for any purpose, change it however you want, and sell it or give it away. The only real requirement is that you keep a copy of the original license and the author's copyright notice with the code.

The license is named after the Massachusetts Institute of Technology, which created it. It is short — about 170 words — and written in plain language, which is why many developers choose it. If you find software under the MIT License, you do not need to ask permission to use it, and you do not have to share your changes back to the original author.

Key Takeaways

  • MIT License software can be used, modified, and sold for any purpose without asking the original author for permission.
  • You must include the original copyright notice and license text when you use or distribute the software, even if you have changed it.
  • The license provides no warranty — if the software breaks or causes problems, the original author is not responsible.
  • Unlike some other open-source licenses, MIT does not require you to share your changes or use the same license for your own work.

What you can do with MIT-licensed software

MIT License software can be used in almost any way. You can use it in a personal project, a business application, or a commercial product. You can modify the code to fix bugs, add features, or adapt it to your needs. You can combine it with other software, including software under different licenses. You can sell a product that includes MIT-licensed code without paying the original author anything.

The only condition is that you must include the original license text and copyright notice somewhere in your project — usually in a file called LICENSE or in the source code comments. This requirement applies even if you have heavily modified the code. It applies whether you are sharing the code publicly or keeping it private.

What you cannot do, and what you are not responsible for

The MIT License does not give you the right to claim you wrote the original software. You must keep the author's name and copyright notice intact. You also cannot hold the original author responsible if the software causes problems — the license explicitly states that the software is provided "as is" with no warranty of any kind.

If the software breaks your computer, loses your data, or causes financial loss, you cannot sue the author. This is true even if the problem was caused by a bug in the code. The author provides the software for free and takes no responsibility for how it works or what happens when you use it.

How MIT differs from other common open-source licenses

The GPL (GNU General Public License) is much stricter. If you use GPL software in your project, you must release your entire project under the GPL as well — you cannot keep your own code private or proprietary. MIT has no such requirement. You can use MIT-licensed code in a closed-source, commercial product without sharing your code.

The Apache License 2.0 is similar to MIT but longer and more detailed. It includes explicit language about patents and is often used by larger companies. The BSD License is also very similar to MIT — so similar that many developers treat them the same way. The main difference is that some versions of BSD have an extra clause about endorsement, which MIT does not.

If a license says you must share your changes or use the same license for derivative work, it is not MIT. MIT is the most permissive option — it trusts you to do what you want with the code.

Where you will see the MIT License

MIT is the most popular license on GitHub, the largest code-sharing platform. Many widely used libraries and frameworks use it, including React (a web development tool), Node.js (a JavaScript runtime), Rails (a web framework), and jQuery (a JavaScript library). If you use any of these tools, you are using MIT-licensed code.

You will also see MIT on smaller, single-purpose libraries and tools. Because the license is so simple and permissive, developers often choose it when they want to share code without legal complexity. If you are looking at open-source code and want to know what you can do with it, checking the license file is the first step.

How to use MIT-licensed code in your own project

If you want to use MIT-licensed software, download it or install it however the project recommends — usually through a package manager like npm, pip, or apt. You do not need to contact the author or get permission. Read the license file to see the exact copyright notice and author name.

When you distribute your project (whether you are sharing it publicly or giving it to a client), include a copy of the MIT License and the original copyright notice. Many projects keep this in a file called LICENSE at the root of the project folder. Some projects list all their dependencies and their licenses in a separate file. Check the original project's README to see how they recommend you handle attribution.

Frequently Asked Questions

Can I use MIT-licensed code in a commercial product?

Yes. You can use it, modify it, and sell the product without paying the original author or asking permission. You only need to include the original license and copyright notice somewhere in your project or documentation.

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

No. You can modify the code and keep your changes private. You do not have to contribute your improvements back to the original project. This is one of the main differences between MIT and licenses like GPL.

What happens if the MIT-licensed software breaks something?

The author is not responsible. The license explicitly disclaims all warranties. If the software causes problems, you cannot sue the original author. You use it at your own risk.

Can I change the MIT License or remove it?

You cannot remove the original license or copyright notice from the code you distribute. You can add your own license on top of it if you want, but the original must remain. The license is part of the legal agreement that lets you use the code in the first place.

Is MIT the same as open-source?

MIT is one type of open-source license, but not all open-source software uses MIT. Open-source means the source code is publicly available. MIT is a specific legal agreement about what you can do with that code. Other open-source licenses have different rules.