JA4 Fingerprint Directory

q13d0312h3_55b375c5d22e_da69250d5c8d

Headless Chrome — inferred from the User-Agent on its requests.

What this fingerprint encodes

Transport

QUIC

TLS version

TLS 1.3

Server name

server name sent

Cipher suites offered

3

Extensions offered

12

ALPN

h3

The hello it was computed from

Recovered because the proxy now stores the pre-hash JA3 string alongside the digest. Every number below came out of this client's ClientHello; anything we cannot name in the IANA registry is shown as its raw value rather than guessed at.

Version

TLS 1.2

Cipher suites 3

• TLS_AES_128_GCM_SHA256
• TLS_AES_256_GCM_SHA384
• TLS_CHACHA20_POLY1305_SHA256

Extensions 12

• server_name
• encrypted_client_hello
• supported_versions
• key_share
• 17613 (0x44cd)
• quic_transport_parameters
• supported_groups
• psk_key_exchange_modes
• signature_algorithms
• 51764 (0xca34)
• application_layer_protocol_negotiation
• compress_certificate

Named groups 4

• SecP256r1MLKEM768
• x25519
• secp256r1
• secp384r1

771,4865-4866-4867,0-65037-43-51-17613-57-10-45-13-51764-16-27,4588-29-23-24,

Seen in live traffic

Connections

1

First seen

2026-08-23 14:34 UTC

Last seen

2026-08-23 14:34 UTC

Transport

QUIC

User-Agents seen on this fingerprint

• Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) HeadlessChrome/145.0.0.0 Safari/537.36 1×

A User-Agent is self-declared and trivially forged, so this names an observation rather than proving an identity. It is still the strongest signal available: the fingerprint comes off the TLS handshake and the User-Agent off the request that followed, and one client build keeping a stable JA4 while changing what it calls itself is a finding in its own right.

This entry is an observation, not a policy decision. It is here because the edge saw it, not because anyone reviewed it, and it blocks nothing on its own. Only the curated tier drives classification and banning.