SESKStuff Everyone Should Know
SESK: Stuff Everyone Should Know · sesk.info/tech-mit-license-permissive

The MIT License lets almost anyone reuse code. What is its main condition?

Keep the copyright and permission notice in copies of the software.

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  1. Share all your changes publicly
  2. Keep the copyright and license notice ✔
  3. Pay a fee for commercial use

Why: The MIT License is permissive, not copyleft. You can use, change, and even sell the code inside closed software, as long as you include the original copyright notice and license text.

Huh, didn't know that: The GNU Project calls this the Expat license and describes it as lax, permissive, and compatible with the GPL.

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The MIT License is so relaxed, its only rule is: please remember my name.
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References

Answer: Keep the copyright and license notice. The MIT License is permissive, not copyleft. You can use, change, and even sell the code inside closed software, as long as you include the original copyright notice and license text.

  1. Open Source Initiative: The MIT License opensource.org/license/mit
    The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software
    Checked 2026-10-10.
  2. GNU Project: Various Licenses and Comments about Them www.gnu.org/licenses/license-list.html
    This is a lax, permissive non-copyleft free software license, compatible with the GNU GPL.
    Checked 2026-10-10.

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