Note: This article was originally published on the Memgraph blog.
The MIT License is a short, simple, and permissive software license. It grants users the liberty to do virtually anything they wish with the software and associated documentation files, including use, copy, modify, merge, publish, distribute, sublicense, and sell copies of the software. The only condition is that the license and copyright notice must be included in all copies or substantial portions of the software.
Understanding This License
The MIT License’s simplicity and brevity differentiate it from others. Unlike the GPL, which is extensive and complex, the MIT License is easy to understand and does not require a legal expert to interpret its terms. Unlike some licenses, MIT allows you to keep the source code of any modifications to yourself.
License Variations
Expat License
The Expat License got its name from the Expat XML parser library. The library was licensed under what we often refer to as the “MIT License,” but due to confusion with other licenses related to MIT, it’s sometimes specified as the Expat License to avoid ambiguity.
MIT No Attribution License (MIT-0)
A variant where all attribution clauses have been removed. There’s no requirement to include the original copyright notice and permission notice in any copies of the software.
JSON License
Includes an additional clause stating “The Software shall be used for Good, not Evil.” Created by Douglas Crockford, who developed the JSON data format.
The X11 License
Named after the X Window System from MIT, this variant includes an additional disclaimer clause to distance MIT and X Consortium from any potential legal implications.
Benefits and Limitations
Benefits
- Simplicity: Easy to understand without needing extensive legal expertise
- Permissiveness: One of the most permissive licenses available
- Open collaboration: Fosters an environment of open collaboration
- Corporate appeal: Permits use without requiring disclosure of proprietary information
Limitations
- No warranty: Software is provided “as is” without guarantees
- No liability: Copyright holders are not responsible for any damage caused by the software
- No requirement for open-source derivative works: Unlike GPL, does not require adaptations to remain open source
Comparing the MIT License to Other Licenses
MIT vs. GNU GPL
The GPL is a “copyleft” license: any modifications or derivative works must also be distributed under the GPL. The MIT License does not have a copyleft requirement, giving developers more flexibility.
MIT vs. Apache License 2.0
Both are permissive, but the Apache License includes a provision that grants an explicit patent license, protecting users from patent claims by contributors. The MIT License does not include an explicit contributor’s patent license.
MIT vs. BSD Licenses
The key difference lies in the advertising clause found in the original BSD License, which requires acknowledgment of contributors in advertising materials. Neither the MIT License nor the later BSD licenses include this requirement.
Takeaway
The MIT License is worth considering if you’re a developer working on an open-source project. It provides freedom while maintaining simplicity, making it accessible and easy to understand. A well-chosen license is not only about adhering to legal requirements but also about creating a healthy, collaborative, and inclusive community around your software.