Open Source CAPTCHA & Bot Protection Software
CAPTCHA & Bot Protection software prevents automated scripts and malicious bots from abusing web forms and APIs. These tools filter incoming HTTP traffic to block scrapers, AI crawlers, and spam submissions. This type of software is for developers and site administrators who need to stop brute force login attempts and resource exhaustion. Self-hosting these apps ensures that user interaction data and IP logs remain on private servers. This approach removes the need to send visitor traffic through external verification services to prove human identity.
This page lists 8 open source tools in the CAPTCHA & Bot Protection category. The most popular are SafeLine, Anubis and BunkerWeb. Most use the MIT or AGPL-3.0 license, and 7 offer an official Docker image.
SafeLine
A self-hosted web application firewall and reverse proxy that filters and monitors HTTP traffic to block exploits.
Anubis
Filters incoming HTTP requests using challenges to protect upstream resources from AI crawlers and scraper bots.
BunkerWeb
A web application firewall and reverse proxy that provides secure by default protection for web services.
Cap
A lightweight bot protection system using proof-of-work and instrumentation challenges to replace visual puzzles and tracking.
ALTCHA
A self-hosted spam protection system using proof-of-work mechanisms to replace traditional visual CAPTCHA puzzles.
mCaptcha
A privacy respecting proof of work system that protects websites from bots without requiring image solving.
IPBan
Blocks malicious IP addresses by detecting failed login attempts from event viewers and log files.
UUSEC WAF
A web application firewall and API security gateway featuring AI and semantic analysis for threat detection.
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