Top 7 spam-protection Open-Source Projects

nginx-ultimate-bad-bot-blocker

11 3,667 9.8 Shell

Nginx Block Bad Bots, Spam Referrer Blocker, Vulnerability Scanners, User-Agents, Malware, Adware, Ransomware, Malicious Sites, with anti-DDOS, Wordpress Theme Detector Blocking and Fail2Ban Jail for Repeat Offenders

Project mention: Nginx Bad Bot and User-Agent Blocker | news.ycombinator.com | 2024-03-07

mCaptcha

11 1,563 8.6 Rust

A no-nonsense CAPTCHA system with seamless UX | Backend component

Project mention: So much for CAPTCHA then – bots can complete them quicker than humans | news.ycombinator.com | 2023-08-16

What about proof of work based CAPTCHA like https://github.com/mCaptcha/mCaptcha ? Since CAPTCHAs can be solved by bots, at least make it more costly for them.

SurveyJS

surveyjs.io sponsored

Open-Source JSON Form Builder to Create Dynamic Forms Right in Your App. With SurveyJS form UI libraries, you can build and style forms in a fully-integrated drag & drop form builder, render them in your JS app, and store form submission data in any backend, inc. PHP, ASP.NET Core, and Node.js.
apache-ultimate-bad-bot-blocker

3 740 9.5 C

Apache Block Bad Bots, (Referer) Spam Referrer Blocker, Vulnerability Scanners, Malware, Adware, Ransomware, Malicious Sites, Wordpress Theme Detectors and Fail2Ban Jail for Repeat Offenders
friendly-challenge

3 386 6.3 TypeScript

The widget and docs for the proof of work challenge used in Friendly Captcha. Protect your websites and online services from spam and abuse with Friendly Captcha, a privacy-first anti-bot solution.
spamscanner

4 265 0.0 JavaScript

Spam Scanner is a Node.js anti-spam, email filtering, and phishing prevention tool and service. Built for @ladjs, @forwardemail, @cabinjs, @breejs, and @lassjs.
PoW-Shield

10 203 8.8 TypeScript

Project dedicated to fight Layer 7 DDoS with proof of work, with an additional WAF and controller. Completed with full set of features and containerized for rapid and lightweight deployment.
mosparo

2 160 9.2 PHP

mosparo is the modern solution for protecting your online forms from spam. The protection method is quite simple: mosparo blocks spam using rules matching the form’s data. The detection method is comparable to an e-mail spam filter.

Project mention: mosparo – the modern spam protection is live | news.ycombinator.com | 2023-08-30

WorkOS

workos.com sponsored

The modern identity platform for B2B SaaS. The APIs are flexible and easy-to-use, supporting authentication, user identity, and complex enterprise features like SSO and SCIM provisioning.

NOTE: The open source projects on this list are ordered by number of github stars. The number of mentions indicates repo mentiontions in the last 12 Months or since we started tracking (Dec 2020).