#1
Lightweight, self-hostable CAPTCHA alternative using SHA-256 proof-of-work challenges to protect forms and APIs from bots without tracking or visual puzzles.
7.6k stars551 forkslast commit Actively maintained
3 self-hosted ALTCHA alternatives
ALTCHA is a privacy-focused CAPTCHA alternative that uses client-side proof-of-work challenges to verify users and block bots and spam on websites and forms without tracking, designed to be GDPR-compliant.
Alternatives to ALTCHA
#2
Accessible, rule-based spam protection for web forms that inspects form fields, stores minimal data encrypted, and auto-deletes entries after 14 days.
305 stars17 forksMITlast commit Actively maintained
Privacy-first, GDPR-focused self-hosted Proof-of-Work CAPTCHA for forms and APIs with an adaptive lightweight widget and Postgres/ClickHouse backend.
187 stars7 forkslast commit Actively maintained
What replacing ALTCHA actually involves
Every option on this page is open source and free to run on your own hardware, so you own the data and there is no subscription to cancel. 3 of 3 shipped a commit in the last six months. Licences in this list: MIT. In exchange you take on hosting, backups and updates yourself.
Browse everything in Moderation & Anti-Spam Tools.
