---
title: "CAPTCHA"
url: https://proxy.wiki/glossary/captcha/
type: Glossary Term
author: "proxy.wiki editorial"
published: 2026-08-19
updated: 2026-08-19
site: proxy.wiki
topics: ["Proxy fundamentals"]
license: CC BY 4.0 — quote freely with attribution to https://proxy.wiki/
---

# 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](/glossary/asn/), the [TLS fingerprint](/glossary/tls-fingerprinting/), the request rate, or the [browser fingerprint](/glossary/browser-fingerprinting/). 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.