ja4s

JavaScript TLS 1.3/1.2 implementation for Node.js, with full control over cryptographic keys and record layer.

JA4+ Fingerprinting Library in Golang

JA4+ Fingerprinting Library in Python

A Rust-based TLS handshake inspector for live servers and pcaps, with JA3/JA4/JA4S fingerprints, raw byte parsing, negotiated cipher suite breakdown, and pretty readable reports

CounterAgent SDK — AI agent detection and fingerprinting. Identify autonomous agents by their TLS and HTTP signatures.

Standalone nginx module for JA4, JA4S, and JA4H TLS/HTTP fingerprinting. No nginx core patch, no OpenSSL patch. Just drop in and build.