Reverse proxy for the hot path: passive TLS, HTTP/2, and TCP SYN (eBPF) fingerprints, injected as trusted headers. Built to stay fast with fingerprinting on.
Open source all the way down. Fingerprints come from Huginn Net, proxy and signature engine alike, dual-licensed MIT/Apache-2.0. No proprietary core, no separate license for commercial use.

Values are produced by the proxy and override any client-supplied spoofed headers.
| Header | Layer / note |
|---|---|
x-tls-ja4 (+ -r / -o / -ro) | TLS ClientHello: FoxIO-LLC JA4 family (hashed & raw variants) |
x-tls-ja4-s1 (+ -rs1) | TLS ClientHello: stable JA4 (ephemeral extensions excluded) |
x-http2-akamai | HTTP/2 only |
x-tcp-p0f | TCP SYN via eBPF (XDP or TC) when enabled |