Install libpsl with Homebrew

Project links

• Homepage
• Repository

Commands and aliases

• psl
• psl-make-dafsa

Project history

The library was created by Tim Ruehsen from libmget cookie code on 2014-03-19, according to the source changelog, and the public GitHub repository was created on 2014-03-20. The README describes libpsl as a C library that handles the Public Suffix List with built-in PSL data, file-loaded PSL data, DAFSA compression, thread safety, and IDNA support.

The Public Suffix List itself is a cross-vendor initiative maintained by Mozilla volunteers and registry submissions. libpsl packages that ecosystem for C consumers rather than trying to define suffix policy itself.

Adoption history

libpsl's adoption comes from web-client and network-client needs: software must avoid supercookies, reject overbroad certificate or domain assumptions, and group sites by registrable domain. The Public Suffix List page names browsers, Qt, crawler libraries, certificate-authority workflows, and security tooling as users of PSL data.

Package managers carry libpsl because many lower-level network tools need PSL behavior without embedding their own parser. Homebrew, Debian-family systems, Fedora, MacPorts, Nix, Arch, Alpine, and openSUSE all appear in the package metadata for this batch.

How it is used

Developers use libpsl through the C API to test whether a domain is a public suffix, verify cookie-domain acceptability, find public or private domain portions, or load updated PSL data. The package also ships the `psl` command and `psl-make-dafsa` for command-line inspection and compressed list generation.

Why package nerds care

libpsl is package-nerd significant because it is tiny infrastructure with security consequences. A stale or missing PSL layer can allow cookie scoping mistakes or bad domain-boundary assumptions, while a shared library lets distributions update the logic and data path centrally.

Its build and packaging details are also unusually nerdy: the README separates libpsl releases from PSL data updates, supports both autotools and Meson, and uses DAFSA compression to shrink lookup data for fast native access.

Timeline

• 2014-03-19: Source changelog says Tim Ruehsen created the library from libmget cookie code.
• 2014-03-20: The public GitHub repository was created.
• 2016-01-02: Release 0.12.0 appears in GitHub release metadata.
• 2019-04-16: Release 0.21.0 was published.
• 2026-06-24: Release 0.22.0 included portability, build, Windows, Apple ICU, and tarball-build improvements.

Related projects

• The Public Suffix List, Mozilla's PSL maintenance process, Chromium's DAFSA code, GNU Wget/libmget history, curl-like clients, browsers, crawler libraries, and certificate-authority tooling are the related ecosystem.

Sources

• https://api.github.com/repos/rockdaboot/libpsl
• https://api.github.com/repos/rockdaboot/libpsl/releases
• https://formulae.brew.sh/formula/libpsl
• https://github.com/publicsuffix/list
• https://github.com/rockdaboot/libpsl
• https://publicsuffix.org/learn/
• https://raw.githubusercontent.com/rockdaboot/libpsl/master/README.md
• https://raw.githubusercontent.com/rockdaboot/libpsl/master/src/psl.c