[mmarian]

If someone invests time/money in using a captcha solver, they're already dedicated enough and will easily get around a JA4 signature block.

Maybe there's some one-off exercise where this is useful, but it's very rare and I've seen people waste so much time with the whack a mole JA4 block just because they like the intellectual challenge.

[arbol]

It's not hard to setup JA4 monitoring and I think its valid as a coarse filter. There are various plugins for nginx/node.

> I've seen people waste so much time with the whack a mole JA4 block just because they like the intellectual challenge

You just store the ja4 on requests and build a catalogue of known JA4s over time using statistics. Outlier JA4s you treat with suspicion by default and challenge. It shouldn't be manual.

> If someone invests time/money in using a captcha solver, they're already dedicated enough and will easily get around a JA4 signature block.

Obviously, not for the regular user but captcha solvers are also blockable: - proxy detection - detection by running DNS server and capturing real IP over UDP request - abnormal TLS handshake latency - repeat behaviour at scale - rendering captcha on a fake origin instead of in the real page