CAPTCHA
A challenge intended to separate humans from automation, and usually a symptom rather than the problem itself.
A CAPTCHA is a test presented when a system is uncertain whether a visitor is human. Modern implementations mostly score behaviour silently and only show a visible puzzle when the score is poor.
#Treat it as a symptom
By the time a challenge appears, something earlier already looked wrong: the network, the TLS fingerprint, the request rate, or the browser fingerprint. Solving the challenge without addressing the cause means solving one on every request, which is slow and expensive.
#The order that actually works
- Find out which signal is triggering suspicion.
- Fix that — often the client stack rather than the proxy.
- Reduce request rate and make timing less mechanical.
- Only then consider solving services, and only for the residual cases.
#Note on legality
Automated circumvention of access controls is restricted in some jurisdictions and prohibited by many sites’ terms. Whether you may do it is a separate question from whether you can.