The MIT License: in Plain English

The MIT License is one of the most popular open-source licenses today. If you're a software developer and haven't taken the time to read the license, you need to do so now. The chance is high that the libraries you use, use the MIT License. Notable examples include Ruby on Rails, Node.js, jQuery, and React.

Photo by Álvaro Serrano

Disclaimer: I should note that I’m NOT an attorney or an expert in the subject of license, trademark, and copyright law. I’m merely a software developer trying to understand better the license I am working with every day.

Before we dive into “translating” the MIT License to plain English, let's look at its history. The MIT License is a permissive free—free, as in freedom*—software license that originated at the Massachusetts Institute of Technology (MIT). According to Gordon Haff, the origin of the MIT License is a mysterious one, and it's hard to pin its inception to an exact date, but 1987 seems to be the single best answer.¹ It is important to note that it was frequently changed over the years. However, a generic MIT-style license form was standardized as _The MIT License* by the Open Source Initiative and Software Package Data eXchange groups.²

Reading the original

Now that you have a basic overview, let's begin by reading the original standardized MIT License by the Open Source Initiative; it is a good idea to have the whole in mind.

The MIT License

Copyright (c) <year> <copyright holders>

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.

In Plain English

Here is my attempt at translating it into plain English; if you are more interested in reading an in-depth analysis, then check out Kyle E. Mitchell's The MIT License, Line by Line.

What I can do

• I can use the software for commercial use.
• I can use the software for private use.
• I can distribute copies of the software.
• I can modify the software to my liking.
• I can sublicense the software and—or sell it.

What I cannot do

• I can NOT hold the author liable for the software.
• I do not have warranty for the software.

What I must do

• I must include the copyright and license notices in all copies or substantial uses of the software.

Summary

In just one hundred seventy words, the MIT License gets a lot of legal work done; as long as we include the original copyright and license notice, we can do whatever we want; the MIT License clears a path for open-source software by granting permission for the software to everyone, for free, while protecting the authors from liabilities and warranties.