structured-public-domains

Compact Public Suffix List (PSL) for Rust.

• 35KB embedded data (JSON trie compressed with zstd)
• ~3M lookups/sec on a single core (~325 ns per lookup)
• O(depth) trie walk (typically 2-3 steps)
• Wildcard (*.jp) and exception (!metro.tokyo.jp) rules
• Based on the official Public Suffix List (ICANN and private sections)
• Auto-updated monthly from publicsuffix.org

Terminology: A public suffix (e.g., com, co.uk) is the part of a domain under which users can register names. The registrable domain (eTLD+1) is one label above the suffix (e.g., example.co.uk).

Usage

use structured_public_domains::{lookup, registrable_domain, is_known_suffix};

let info = lookup("www.example.co.uk").unwrap();
assert_eq!(info.suffix(), "co.uk");
assert_eq!(info.registrable_domain(), Some("example.co.uk"));
assert!(info.is_known());

// Helpers
assert_eq!(registrable_domain("sub.example.com"), Some("example.com".to_string()));
assert!(is_known_suffix("example.com"));

Performance

Benchmarks on Apple M-series (criterion, cargo bench):

Runtime memory: The PSL trie is decompressed and parsed lazily on first call (OnceLock), then cached for the lifetime of the process. Runtime footprint is ~1.1 MB (10,835-node trie with ~9,000 suffix rules). The 35KB compressed blob is embedded in the binary at compile time.

Why not psl?

Both crates have comparable lookup speed. psl trades a larger binary for zero runtime dependencies. structured-public-domains trades a smaller binary and auto-updates for a zstd dependency (C FFI; pure Rust via structured-zstd is planned — see #9).

Support the Project

USDT (TRC-20): TFDsezHa1cBkoeZT5q2T49Wp66K8t2DmdA

License

Apache License 2.0