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Overview

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OpenCaptcha is software that generates CAPTCHA images from text, symbols, and digits. OpenCaptcha is open-source and has a publicly available API free for anyone to use.

Below are examples of CAPTCHA images generated by OpenCaptcha.

Example of a CAPTCHA

Features​

  • Open Source
    The source code is available on GitHub.

  • Free, Public API
    Access a fully open, cost-free CAPTCHA service at api.opencaptcha.io without needing API keys or facing usage limits.

  • Self-Hosting Option
    Host OpenCaptcha on your own infrastructure for total control over uptime, security, and scalability. Please see the Self-Hosting section.

  • Multilingual Support
    Generate CAPTCHA images in Mandarin, English, Arabic, and many other languages.

  • Flexible & Customizable
    Adjust dimensions, CAPTCHA difficulty levels, and text input to meet your needs.