Open-source licenses explained
Every app page shows the app's license, and a Free software badge when it is one of the licenses below. This page says, in plain language, what each lets you do. It is a summary, not legal advice: the license text is what counts, and each section links to it.
The short version
Using an app is never restricted by these licenses. Install it, run it at home or at work, as often as you like, for free. The licenses only add conditions when you share the software with others or change it — which most people never do.
They come in two families:
- Permissive (MIT, BSD, Apache): do almost anything, including using the code in a closed product; just keep the copyright notice.
- Copyleft (GPL, LGPL, AGPL, and MPL for single files): you may share and change the software, but what you give others must stay under the same license, with its source code.
MIT
The most common license on Tuxery, and one of the simplest. You can use, copy, modify, merge, publish, sell and sublicense the software. The one condition: keep the copyright notice and the license text with copies. No warranty. The ISC license is the same thing in fewer words, and X11 an older variant. License text
BSD
Like MIT. The 2-clause version asks you to keep the copyright notice; the 3-clause version also forbids using the authors' names to promote what you make from it without permission. No warranty. BSD-3-Clause text · BSD-2-Clause text
Apache 2.0
Permissive like MIT, written by lawyers for companies. Two additions: if you share a modified version, mark the files you changed; and every contributor grants you a license to any patent their contribution uses — which ends if you sue someone over those patents. License text
MPL 2.0
The Mozilla Public License — Firefox's. Copyleft, but per file: if you share a modified version, the files you changed stay under the MPL with their source available; the rest of your project can be under any license, closed or open. License text
LGPL
The "Lesser" GPL, mostly used by libraries. Programs can use an LGPL library whatever their own license, closed ones included, as long as users can replace the library with their own modified version. Changes to the library itself stay under the LGPL, with source. Versions 2.1 and 3 differ in details. LGPL-3.0 text · LGPL-2.1 text
GPL 2.0
The GNU General Public License, version 2 — the Linux kernel's. You can use, share and modify the software. If you share it, modified or not, you must give the recipients the source code, under the same license, with the same freedoms — no extra restrictions. Software that includes GPL code and is shared becomes GPL as a whole. "GPL-2.0-only" means exactly this version; "or later" lets you pick a newer one. License text
GPL 3.0
The same deal as GPL 2.0, updated: it also covers patents (contributors can't sue you over the code they gave), forbids locking devices so users can't run modified versions ("tivoization"), and fits better with other free licenses such as Apache 2.0. Most "GPL3" apps on Tuxery are this version or later. License text
AGPL 3.0
The GPL 3.0 plus one rule for software used over a network: if you run a modified version as a service others use (a website, a server), you must offer them its source code too — not only when you hand out copies. Tuxery itself is AGPL — see its license. License text
Public domain
The Unlicense, CC0 and WTFPL give up the authors' rights as far as the law allows: no conditions at all, not even keeping a notice. Unlicense · CC0
Several licenses
An app can carry several licenses at once — "Apache-2.0 AND MIT" means parts of it are under each, and you follow both; "MIT OR Apache-2.0" lets you pick one. Tuxery shows the Free software badge when every license involved is a free one.
Other licenses
Hundreds of other licenses exist. For any of them, the SPDX license list has the full text, and choosealicense.com compares the common ones side by side. When a source only says "custom" or "unknown", Tuxery shows no badge — check the app's own website. Proprietary software is explained in the glossary.