Choosing a license

Version 1.0 · July 2026

Every ISL variant carries the same ethical use restrictions in Sections 4 and 5 — that is the constant across the family. What differs is what others may do with your work: modify it, sell it, redistribute it, or merely look at it. Answer the questions below in order and you will land on the right variant.

1. Is this software, or a non-software creative work?

Source code, applications, libraries, and firmware are software. Text, images, audio, video, and courseware are creative works. The two families share Sections 4 and 5 but nothing else — go to Question 2 for software or Question 5 for creative works.

2. (Software) Do you want to permit commercial use?

If you want to forbid anyone from selling the software, building a paid product on it, or offering it as a paid service, choose ISL-NC and stop here: it permits use, modification, and redistribution, but only for non-commercial purposes, with attribution required.

If commercial use should be allowed, continue to Question 3.

3. (Software) Do you want to permit modification and redistribution?

If you want people to be able to use the software, including internally for commercial purposes, but never modify or redistribute it, choose ISL-R and stop here: the source is visible for transparency and inspection, not for reuse.

If you are distributing a closed-source product where end users never see the source at all — an installed application or a hosted service with a click-through agreement — choose ISL-EULA and stop here: it is a proprietary end-user license template, not a source-available license.

If modification and redistribution should both be allowed, continue to Question 4.

4. (Software) Should derivatives stay under the same license?

If you want the least friction possible — no attribution, no copyleft, and you would rather maximize adoption and let others relicense their derivatives freely (the ethical restrictions still travel with every copy regardless), choose ISL-P and stop here: it is the family's most permissive software variant.

If derivatives must stay under the same license and disclose their source — a copyleft, share-alike guarantee — you have three strengths to choose from. If your software is typically used as a whole program or service and you want the strongest guarantee, including when it's only reached over a network rather than distributed as a copy, choose ISL-NETC: modified versions run as a network service or SaaS trigger the same source-disclosure duty as distributing the software, closing the so-called SaaS loophole. If you want that same whole-program guarantee but without the network trigger, choose ISL-C. This is the waqf model: what is endowed to the community remains endowed. If instead your software is meant to be used as a library or component — where you want modified files of your code to stay under the same license, but you are happy for other code to link or combine with it under different terms — choose ISL-LC, a weaker, file-level copyleft.

5. (Creative works) Do you want any conditions beyond the ethical ones?

For non-software creative works — text, art, music, video, courseware — start with the same question as software. If you want the least friction possible — no attribution required, just the family's ethical restrictions — choose ISL-CW-0 and stop here. This is not a CC0-equivalent public-domain dedication: Sections 4 and 5 still bind every copy.

If you want attribution and want to decide on derivatives and commercial use, continue to Question 6.

6. (Creative works) Do you want to permit commercial use?

If commercial use should be prohibited, continue to Question 7 for the NonCommercial branch. If commercial use should be permitted, continue to Question 7 for the branch without NonCommercial in the name — both branches ask the same follow-up question about derivatives.

7. (Creative works) Do you want to permit adaptations, and if so, must they share alike?

If you want to prohibit any adaptations or derivatives — others may only share your work unmodified, with attribution — choose ISL-CW-ND (commercial use allowed) or ISL-CW-NC-ND (non-commercial only).

If you want to permit adaptations but require that anyone who adapts your work release their version under the same license — a share-alike guarantee, like ISL-C for creative works — choose ISL-CW-SA (commercial use allowed) or ISL-CW-NC-SA (non-commercial only).

If you want to permit adaptations with no restriction on how the adapted version is licensed — attribution is the only condition — choose ISL-CW (commercial use allowed) or ISL-CW-NC (non-commercial only).

Summary table

Still unsure? The comparison table on the home page lists every permission side by side, and the FAQ answers common questions about scope and enforcement. Once you have chosen, the how-to-apply guide walks through adding the license file, SPDX identifiers, and source headers.