MIT vs Proprietary License

MIT License compared with Proprietary / commercial licence: what each licence allows, and whether code under one can be used in a project under the other. Results are generated by the open-source license compatibility checker.

Quick Answer

Compatibility is directional, so both directions are answered separately (distributed software):

MIT code in proprietary software

Generally Compatible

Using MIT-licensed code in a proprietary project is generally compatible in this scenario.

MIT generally allows the code to be included in proprietary software without releasing your source code, provided its notices are kept.

proprietary code in a project licensed under MIT

Manual Review Required

Using Proprietary-licensed code in a project under MIT requires review of the actual licence terms.

The component is under proprietary terms. Whether it may be used, modified, redistributed, resold or white-labelled depends entirely on the specific licence agreement.

Key Differences

Type: MIT: open source; Proprietary: proprietary.
OSI approved: MIT: yes; Proprietary: no.
Commercial use: MIT: permitted; Proprietary: depends on the licence agreement.
Modification: MIT: permitted; Proprietary: depends on the licence agreement.
Distribution: MIT: permitted; Proprietary: depends on the licence agreement.
Network-use (SaaS) clause: MIT: no; Proprietary: depends on the licence agreement.
Source disclosure: MIT: not required; Proprietary: depends on the licence agreement.
Same licence for distributed changes: MIT: no; Proprietary: depends on the licence agreement.
Attribution / notices: MIT: yes; Proprietary: depends on the licence agreement.
Mark modified files: MIT: no; Proprietary: depends on the licence agreement.
Express patent licence: MIT: no; Proprietary: depends on the licence agreement.
Patent termination clause: MIT: no; Proprietary: depends on the licence agreement.

Comparison Table

	MIT	Proprietary
Type	Open source	Proprietary
OSI approved	Yes	No
Commercial use	Permitted	Depends on the licence agreement
Modification	Permitted	Depends on the licence agreement
Distribution	Permitted	Depends on the licence agreement
Copyleft	None	None
Network-use (SaaS) clause	No	Depends on the licence agreement
Source disclosure	Not required	Depends on the licence agreement
Same licence for distributed changes	No	Depends on the licence agreement
Attribution / notices	Yes	Depends on the licence agreement
Mark modified files	No	Depends on the licence agreement
Express patent licence	No	Depends on the licence agreement
Patent termination clause	No	Depends on the licence agreement
Trademark rights granted	Not addressed	Not addressed

Commercial Use

MIT: permitted.
Proprietary: depends on the licence agreement.

MIT code in proprietary software: MIT permits commercial use.
proprietary code in a project licensed under MIT: The component is under proprietary terms. Whether it may be used, modified, redistributed, resold or white-labelled depends entirely on the specific licence agreement.

Proprietary Software

MIT code in closed-source commercial software

Generally Compatible

Using MIT-licensed code in a proprietary project is generally compatible in this scenario.

MIT generally allows the code to be included in proprietary software without releasing your source code, provided its notices are kept.

MIT code in closed-source commercial software: MIT generally allows the code to be included in proprietary software without releasing your source code, provided its notices are kept.

SaaS

Network-use clause: MIT: no; Proprietary: depends on the licence agreement.

MIT code in a closed-source SaaS

Generally Compatible

Using MIT-licensed code in a proprietary project is generally compatible in this scenario.

MIT generally allows the code to be included in proprietary software without releasing your source code, provided its notices are kept.

MIT code in a closed-source SaaS: MIT has no network-use (SaaS) clause.

Modification

MIT: permitted.
Proprietary: depends on the licence agreement.

Modifying MIT code used in closed-source software

Generally Compatible

Using MIT-licensed code in a proprietary project is generally compatible in this scenario.

MIT generally allows the code to be included in proprietary software without releasing your source code, provided its notices are kept.

Modifying MIT code used in closed-source software: MIT permits modification.

Distribution

MIT: permitted.
Proprietary: depends on the licence agreement.

MIT code in proprietary software: MIT permits distribution.
proprietary code in a project licensed under MIT: The component is under proprietary terms. Whether it may be used, modified, redistributed, resold or white-labelled depends entirely on the specific licence agreement.

Copyleft

MIT: none copyleft.
Proprietary: none copyleft.

MIT code in proprietary software: MIT has no copyleft.
proprietary code in a project licensed under MIT: Proprietary has no copyleft.

Source Disclosure

MIT: not required.
Proprietary: depends on the licence agreement.

MIT code in proprietary software: MIT does not require you to publish source code.
proprietary code in a project licensed under MIT: See Proprietary source-disclosure conditions.

Attribution

MIT: Include the copyright notice and permission notice in all copies or substantial portions.

MIT code in proprietary software: MIT requires the copyright and licence notices to be kept with copies you distribute.
proprietary code in a project licensed under MIT: Proprietary attribution requirements apply on distribution.

Patent Considerations

Express patent licence: MIT: no; Proprietary: depends on the licence agreement.
Patent termination clause: MIT: no; Proprietary: depends on the licence agreement.

MIT code in proprietary software: MIT contains no express patent licence. Any patent permission would depend on implied licence doctrines, which vary by jurisdiction.
proprietary code in a project licensed under MIT: Patent terms are unknown.

Common Scenarios

Scenario	MIT code in proprietary software	proprietary code in a project licensed under MIT
Use as a dependency / library	Generally Compatible	Manual Review Required
Copy source code into the project	Generally Compatible	Manual Review Required
Modify the component	Generally Compatible	Manual Review Required
SaaS / network service (not distributed)	Generally Compatible	Manual Review Required
Internal / private use only	Generally Compatible	Manual Review Required
Resell the software	Generally Compatible	Manual Review Required
White-label / rebrand	Generally Compatible	Manual Review Required

FAQ

Can I use MIT code in proprietary software?

Using MIT-licensed code in a proprietary project is generally compatible in this scenario. MIT generally allows the code to be included in proprietary software without releasing your source code, provided its notices are kept.

Can I use proprietary code in a project licensed under MIT?

Using Proprietary-licensed code in a project under MIT requires review of the actual licence terms. The component is under proprietary terms. Whether it may be used, modified, redistributed, resold or white-labelled depends entirely on the specific licence agreement.

Do I have to publish my source code when I use MIT code?

MIT does not require you to publish source code.

Can I use MIT code in a closed-source SaaS?

Try the Interactive Checker

Change the scenario, say whether the code is modified, distributed or offered as SaaS, and see every rule that applies.

Check MIT in a Proprietary project Check Proprietary in a MIT project

Related Comparisons

Authoritative Sources

This tool provides general software licensing information and is not legal advice. License obligations may depend on how software components are combined, modified, distributed and used. For high-risk results, review the actual license text before relying on this result.