ISC License Generator

The ISC License explained

The ISC License was authored by the Internet Software Consortium (now Internet Systems Consortium) in 1995 as a deliberately stripped-down alternative to the BSD license. At roughly 100 words, it is even shorter than the MIT License and is one of the most concise permissive licenses ever written. It is OSI-approved and classified by the FSF as a free software license that is fully compatible with the GPL.

The terms are minimal: the license grants permission to use, copy, modify, and distribute the software for any purpose, with or without fee. The only conditions are that the copyright notice and the permission notice must appear in all copies. The software is delivered as-is, with a strong WARRANTY DISCLAIMER that disclaims fitness for any purpose and limits the author's liability.

History and motivation

The Regents of the University of California raised concerns that the original BSD license contained legally redundant language inherited from older Berkeley wording. The ISC drafted a cleaner equivalent, removing those clauses while preserving the same effective rights. The FSF explicitly recommends ISC as functionally equivalent to MIT and the simplified BSD-2-Clause, and prefers ISC for its brevity.

Projects that use ISC

ISC is the default license for new code in OpenBSD — Theo de Raadt adopted it as the project's preferred license for fresh contributions. It also covers the flagship ISC products BIND (the dominant DNS server) and the legacy ISC DHCP server. In the JavaScript ecosystem, the npm registry CLI and many package.json defaults list "license": "ISC", partly because npm init historically suggested it. Various Node.js internal tooling components also use ISC.

ISC vs MIT vs BSD-2-Clause

• ISC vs MIT — functionally identical; ISC is roughly half the length and removes redundant verbs ("use, copy, modify" instead of MIT's longer chain).
• ISC vs BSD-2-Clause — ISC is the cleaned-up successor; BSD-2-Clause still keeps Berkeley-flavored boilerplate.
• ISC vs Apache 2.0 — Apache adds explicit patent grants and a NOTICE requirement; ISC is silent on patents.

SPDX and adoption notes

The SPDX identifier is ISC. Add // SPDX-License-Identifier: ISC at the top of source files and place a LICENSE file at the repository root. Despite its technical superiority in brevity, ISC remains less popular than MIT mainly because of familiarity bias: developers default to what they already know, and MIT dominates GitHub's Choose a License picker.

FAQ

Is ISC equivalent to MIT? Yes — functionally identical permissions and conditions. The only practical difference is wording length.

Does OpenBSD really use it? Yes. OpenBSD adopted ISC as the recommended license for new code; older code remains under BSD.

Does ISC include a patent grant? No, it is silent on patents. For patent-sensitive domains, prefer Apache 2.0.

Is it shorter than MIT? Yes — roughly half the size, with fewer redundant verbs in the grant clause.

Disclaimer. This generator produces a license template — it is not legal advice. For commercial products or patent-sensitive domains, consult an attorney.