Best ISC Licensed Open Source Repositories

The ISC License is a short, permissive license functionally similar to the simplified BSD and MIT licenses. It was originally written by Internet Systems Consortium for their own software, including BIND and dhcpd, and later adopted more broadly, particularly across the Node.js and npm ecosystem, where it became a common default. The license grants permission to use, copy, modify, and distribute the software for any purpose, commercial or otherwise, with or without a fee, as long as the copyright notice and permission notice appear in all copies. That's essentially the entire obligation: no attribution requirements beyond keeping the notice, no share-alike terms, and no patent clauses.

What sets ISC apart from MIT and BSD is mostly wording rather than substance. The Open Source Initiative and various license comparison efforts have noted that ISC is functionally equivalent to the 2-Clause BSD License, just phrased more simply and with some redundant legal language removed from MIT's text. There's no meaningful practical difference in what you're allowed to do with ISC-licensed code versus MIT-licensed code: both let you build proprietary products on top without releasing your own source, and both place the entire compliance burden on preserving a short notice.

Because it imposes almost no friction, ISC is popular for small libraries, command-line tools, and utilities where the maintainer wants maximum reuse without legal complexity. It's especially common in the JavaScript and Node.js package ecosystem. Starship, the cross-shell prompt featured on this page, uses the ISC License.