TLS Fingerprint (JA3 / JA4)
See what your browser looks like at the TLS handshake layer — a fingerprint JavaScript cannot change.
The fingerprint beneath JavaScript
Before any page script runs, your browser completes a TLS handshake whose ClientHello message encodes cipher preferences, extension order and supported groups. Anti-fraud systems hash this into JA3/JA4 signatures — and because spoofing extensions operate in JavaScript, they cannot touch it.
What the fields mean
JA3 hashes version + ciphers + extensions into an MD5; JA4 encodes the same traits into a readable string like t13i1516h2 (TCP, TLS 1.3, 15 ciphers, 16 extensions, HTTP/2 ALPN). Browsers, curl, Python and Go each produce distinct signatures.
Why proxies get caught here
A browser spoofed as Chrome still sends Chrome-inconsistent TLS if traffic actually originates from a Go or Python client — and vice versa. Consistency between the TLS layer and the JavaScript layer is what risk engines verify, and this page shows you your own handshake plainly.
Need the in-depth Chinese version? Read the full guide.
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Frequently asked questions
Why does my JA3 change between browsers or versions?
JA3 covers client configuration, which changes with browser updates, enabled features and platform. It identifies a client stack, not a person — the same person on Chrome and Firefox has two JA3s.
Can I change my TLS fingerprint?
Only by changing the actual TLS stack: using a different browser, a custom client library, or a TLS-level proxy. Browser extensions cannot alter ClientHello.
Does this tool store my fingerprint?
No. The fingerprint is computed live for display. Only an anonymous daily count of browser vs non-browser TLS clients contributes to the site-wide Network Pulse.