* [ALTCHA v3.0.11](https://github.com/altcha-org/altcha) – Self-hosted privacy-first security solution protecting websites and APIs from spam using a proof-of-work mechanism.

* [Telegram Captcha Bot v1.1.18](https://github.com/mxssl/tg-captcha-bot) – Button-based captcha for Telegram supergroups that restricts newcomers and bans users who fail to confirm within a timeout.