reference

Open source licenses, explained

Permissive licenses maximize adoption; copyleft licenses keep forks open. Choosing a license is the first real product decision an open source project makes. Every license below links to the tools using it.

MIT 672 tools
Permissive

Short, simple, the default choice: do what you want, keep the copyright notice, no warranty.

Apache-2.0 527 tools
Permissive

Like MIT but with an explicit patent grant — why many big-company projects pick it.

AGPL-3.0 314 tools
Copyleft (strong)

GPL plus a network clause: if you run modified code as a service, you must publish the source.

GPL-3.0 145 tools
Copyleft (strong)

Derivative works must ship under GPL too. The standard "share-alike" license.

BSD-3-Clause 38 tools
Permissive

MIT plus a ban on using contributors names to endorse derived products.

GPL-2.0 34 tools
Copyleft (strong)

The older GPL; what the Linux kernel stays on. Not compatible with GPL-3.0.

MPL-2.0 33 tools
Copyleft (file-level)

Modifications to MPL files stay open; the rest of your codebase can remain proprietary.

BSD-2-Clause 10 tools
Permissive

Effectively MIT without the "and documentation" flourish. Do what you want, keep the notice.

LGPL-2.1 7 tools
Copyleft (weak)

GPL with a linking exception — proprietary apps may use the library without inheriting copyleft.

ISC 2 tools
Permissive

Functionally identical to MIT, originated by BSD developers.

EPL-2.0 1 tools
Copyleft (weak)

Eclipse Foundation license: commercial-friendly with a source-protection clause for the module itself.