# BSD License The BSD License is a family of permissive open source licenses originating from the University of California, Berkeley, for their Berkeley Software Distribution ([[Unix]] variant) in the late 1980s. BSD licenses are among the simplest and most permissive, requiring only attribution in source and binary distributions. BSD licenses allow proprietary use without requiring source code disclosure. The original 4-clause BSD had an advertising clause that caused compatibility issues; the modern 2-clause and 3-clause variants removed this. BSD-licensed code has been incorporated into proprietary systems including macOS, PlayStation OS, and Windows networking stack. ## BSD License Variants | Variant | Clauses | Notes | |---------|---------|-------| | 4-clause (Original) | 4 | Advertising clause (deprecated) | | 3-clause (New/Modified) | 3 | No endorsement clause | | 2-clause (Simplified/FreeBSD) | 2 | Most permissive | | 0-clause (Zero) | 0 | Public domain equivalent | ## 2-Clause BSD Text (Simplified) The entire license: 1. Retain copyright notice in source 2. Retain copyright notice in binary documentation ## Notable BSD-Licensed Projects - **FreeBSD, OpenBSD, NetBSD**: Operating systems - **Nginx**: Web server - **PostgreSQL**: Database (similar license) - **Go**: Programming language (mixed) ## BSD vs MIT Both are permissive with minimal requirements. MIT is slightly simpler; BSD has more variants. Functionally nearly identical for most purposes. ## References - https://opensource.org/licenses/BSD-3-Clause - https://en.wikipedia.org/wiki/BSD_licenses ## Related - [[MIT License]] - [[Apache 2.0 License]] - [[Unix]] - [[Open Source]] - [[Open Source Initiative (OSI)]]