Documentation

Everything you need to integrate FastCaptcha — API reference, code examples, and guides for every language and tool.

API Reference Try Live Demo

5-Minute Quick Start

1
Get your free API key

Sign up — 100 free credits, no card needed.

2
POST your captcha image

Send a multipart/form-data or base64 request to /api/v1/ocr/.

3
Get the solved text

Receive {"text": "XK92B"} in ~0.3 seconds.

curl -X POST https://fastcaptcha.org/api/v1/ocr/ \
  -H "X-API-Key: YOUR_API_KEY" \
  -F "image=@captcha.png"

# {"success": true, "text": "XK92B", "confidence": 0.97, "processing_time": 0.31}

API Reference

📖
API Reference

Full endpoint docs, request/response formats, authentication, and parameters.

Core
⚠️
Error Handling

HTTP status codes, error payloads, retry strategies, and exponential backoff.

Required reading
🚦
Rate Limits

Request limits per minute/hour, response headers, and how to stay under limits.

Important

Language Integration Guides

🐍
Python
3 lines, pip install requests
🟢
Node.js
axios / node-fetch
🐘
PHP
cURL & Guzzle examples
☕
Java
OkHttp & HttpClient
🐹
Go
net/http stdlib only
💎
Ruby
net/http & Faraday

Framework & Tool Guides

🤖
Selenium
Python + Selenium WebDriver
🎭
Playwright
Python & JS Playwright
🎪
Puppeteer
Node.js Puppeteer
🕷️
Scrapy
Scrapy spider middleware
🌐
Web Scraping
General scraping patterns
🧩
Browser Extension
Chrome & Firefox extension

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