```yaml
product: AlterLab
title: "CAPTCHA — Web Scraping Glossary | AlterLab"
comparison_context: "AlterLab is an alternative to Firecrawl, ScrapingBee, and Bright Data."
source_url: https://alterlab.io/glossary/captcha
```

anti-bot

# CAPTCHA

Completely Automated Public Turing test to tell Computers and Humans Apart — challenges that gate access to content for bots.

CAPTCHA stands for Completely Automated Public Turing test to tell Computers and Humans Apart. CAPTCHAs present visitors with tasks that are easy for humans but — in theory — difficult for automated systems: identifying objects in images, solving puzzles, clicking specific regions, or simply checking a box while behavioural signals are analysed in the background.

Common CAPTCHA implementations include Google reCAPTCHA v2 (image grid challenges), reCAPTCHA v3 (invisible, score-based), hCaptcha (similar to reCAPTCHA v2, privacy-focused), Cloudflare Turnstile (behavioural + JavaScript), and GeeTest (slide and rotate puzzles). Each has its own detection mechanism and evasion profile.

Automated CAPTCHA solving typically works through one of two approaches: human-assisted solving services that route challenges to human workers, or AI-based solvers trained on challenge types. AlterLab's Tier 5 integrates automated challenge resolution for major CAPTCHA providers. For sites that require CAPTCHA solving, the resolution latency (typically 3-30 seconds for human solving) must be accounted for in pipeline design.

### What is CAPTCHA?

Completely Automated Public Turing test to tell Computers and Humans Apart — challenges that gate access to content for bots.

### How does AlterLab handle CAPTCHA?

Automated CAPTCHA solving typically works through one of two approaches: human-assisted solving services that route challenges to human workers, or AI-based solvers trained on challenge types. AlterLab's Tier 5 integrates automated challenge resolution for major CAPTCHA providers. For sites that require CAPTCHA solving, the resolution latency (typically 3-30 seconds for human solving) must be accounted for in pipeline design.

## Related Terms

[Cloudflare Bot ManagementCloudflare's enterprise bot detection suite combining machine learning, browser fingerprinting, TLS fingerprinting, and JavaScript challenges.](https://alterlab.io/glossary/cloudflare-bot-management)[Anti-Bot ProtectionSystems deployed by websites to detect and block automated traffic using TLS fingerprinting, CAPTCHA challenges, and behavioural analysis.](https://alterlab.io/glossary/anti-bot-protection)[Headless BrowserA web browser that runs without a graphical user interface, executing JavaScript and rendering pages exactly as a real browser would.](https://alterlab.io/glossary/headless-browser)[JavaScript RenderingThe process of executing a page's JavaScript in a browser engine before extracting content, required for React, Vue, and Angular SPAs.](https://alterlab.io/glossary/javascript-rendering)

## Extract CAPTCHA data from any website

AlterLab returns clean, structured data from any public URL — no scraper infrastructure needed. Start free, no credit card required.

[View API docs](https://alterlab.io/docs/api/rest)

[Back to Glossary](https://alterlab.io/glossary)