Fingerprinting

Millipede fingerprinting provides deterministic header and browser-context consistency. A stable seed—normally a session token—selects one curated browser profile containing a user agent and ordered Accept-* and Sec-Ch-Ua-* companion headers. Reusing the same seed produces the same profile, including across freshly created generator instances.

use millipede_fingerprint::HeaderGenerator;

let first = HeaderGenerator::new().generate("session-42");
let second = HeaderGenerator::new().generate("session-42");

assert_eq!(first, second);
println!("{}", first.user_agent);

HTTP session integration

Enable generated HTTP profiles with HttpKindBuilder::header_generator(true). The HTTP builder installs its default Millipede user agent before generated headers are applied, and the generator only fills headers that are absent.

That precedence is important: headers supplied by the caller are preserved. Generated companion headers fill gaps, but a generated user agent does not replace the builder's already-present default user agent. The session token supplies the stable seed that keeps the selected companion profile consistent across the session's requests.

Browser-hook integration

For browser pages, add a BrowserFingerprintGenerator to BrowserHooks::defaults() with with_fingerprint(...), then install those hooks on the browser kind builder. Starting from BrowserHooks::defaults() preserves the standard bidirectional cookie synchronization while adding fingerprint headers as a post-page-create hook.

The browser hook derives its seed from the attached session ID. If a page has no session, it uses the stable anonymous seed. It sends the generated user agent and companion headers through the provider-neutral page header interface.

Limitations

This feature is a consistency layer, not complete browser impersonation.

• It does not spoof JavaScript-visible navigator, canvas, or WebGL properties.
• It does not spoof JA3, JA4, or other TLS fingerprints.

TLS impersonation would require a different HTTP client backend. The current crate makes no JavaScript-visible or TLS fingerprint-spoofing claim.

The fingerprint crawl example combines deterministic headers with anti-bot recovery, normalized error statistics, and body snapshots against an offline client. Run it with cargo run -p millipede --features http,fingerprint,storage-memory --example fingerprint_crawl.

Next steps

• See fingerprint crawl for deterministic generation and failure snapshots.
• Reuse the seed and cookie identity described in sessions and proxies.