* [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.

* [Cap standalone@3.1.0](https://github.com/tiagozip/cap) – Lightweight, modern CAPTCHA alternative using SHA-256 proof-of-work focused on privacy and ease of integration.