Open Source Alternatives to Google reCAPTCHA

A CAPTCHA and bot protection service that secures web and mobile applications against automated attacks and fraud. The product uses an adaptive risk analysis engine and machine learning to distinguish between legitimate users and bots by analyzing user behavior, device information, and IP addresses. It provides a score-based detection mechanism to minimize user friction and offers native SDKs for iOS and Android, as well as support for IoT devices via reCAPTCHA Express. The service integrates with web application firewalls to block abusive traffic at the network edge and includes multi-factor authentication to combat credential stuffing. It is deployed as part of the Google Cloud Fraud Defense platform.

Whether you want to cut software costs or escape vendor lock-in, these open source alternatives to Google reCAPTCHA give you an option you fully own. You can self-host them, so your data stays on infrastructure you control. This page lists 1 open source alternative to Google reCAPTCHA. The most popular is mCaptcha. It uses the AGPL-3.0 license and ships an official Docker image.