MIT License - Practical Notes and Best Practices for Business Use

The MIT License is one of the most commonly used licenses in OSS (open source software). Commercial use, modification, redistribution, and sublicensing are all permitted. However, the only mandatory condition is to keep the copyright notice and license text.

What the MIT License Is

The MIT License is an open source license that originated at the Massachusetts Institute of Technology (MIT). Because it is simple and highly permissive, it is used by many well-known OSS projects such as React, jQuery, and VS Code.

Example License Text

MIT License

Copyright (c) 2026 [copyright holder]

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.

Pros and Cons of the MIT License

Item	Details
Commercial use	Allowed
Modification and redistribution	Free
Source code disclosure	Not required
Keeping the copyright notice	Required (the only obligation)
Warranty	None (use at your own risk)
Patent protection	None

Notes for Business Use

1. Keep the Copyright Notice and License Text

The MIT License has one main obligation: keep the copyright notice and the license text.

When distributing source code: include a LICENSE file
When distributing binaries or products: include the license text in documentation or in an About screen

⚠️ Important Removing the copyright notice or license text can create a copyright infringement risk. It cannot be omitted in any distribution format.

2. Understand the “As Is” Clause

Under the MIT License, the software is provided “as is.” Even if there are bugs or vulnerabilities, the copyright holder is not responsible.

If you use OSS in business, you should run your own security reviews and vulnerability scans.

3. Prepare for Patent Risk

The MIT License does not include a patent guarantee. That means patent infringement risk is not zero when you use the software.

For important products, patent clearance research is recommended
If you need patent protection, consider OSS licensed under Apache License 2.0

4. Create an Internal OSS Policy

If your company uses OSS, it helps to document internal rules.

Always check the license before using OSS
Keep a list of the OSS you use, such as dependencies in package.json
Consolidate license information in a file such as LICENSES.txt

Example: Adding an npm Package Under the MIT License to a Product

Check the OSS repository license (look at the LICENSE file on GitHub)
Add it to your product
```
npm install some-mit-library
```
Include the license text when distributing
- For binaries, list it in LICENSES.txt
- For web apps, create an “Open Source Licenses” page
Run security checks and verify patent risk

💡 Tip In projects that use npm, the license-checker package can automatically generate a list of dependency licenses.
npx license-checker --summary

Summary

The MIT License is easy to use and very permissive, but you still need to watch for three points: keeping the copyright notice, the lack of warranty, and patent risk.

Copyright notice: cannot be omitted in any distribution format
No warranty: security management is your responsibility
Patent risk: run patent research for important use cases

Frequently Asked Questions

Q: If I include MIT-licensed OSS in my product, do I have to make my own code MIT too? A: No. The MIT License is not copyleft, so it does not force your own code to use the same license. However, you must keep the license text for the MIT-licensed library parts.

Q: If I use MIT-licensed OSS in a web service (SaaS), do I need to display the license text? A: In general, license display obligations are usually considered necessary for distributed software, not internal use or SaaS where the software is not distributed. Still, it is recommended to clearly indicate which OSS you use.

Q: Do I need to check the licenses of all npm dependencies? A: Yes, it is recommended for commercial products. Tools like license-checker can review them in bulk.