* [ALTCHA v3.3.0](https://github.com/altcha-org/altcha) – Self-hosted privacy-first security solution protecting websites and APIs from spam using a proof-of-work mechanism.

* [ALTCHA JS Library v2.6.0](https://github.com/altcha-org/altcha-lib) – Lightweight, zero-dependency JavaScript library for creating and verifying ALTCHA challenges.

* [FCaptcha v1.43.0](https://github.com/WebDecoy/FCaptcha) – Detect bots, vision-based AI agents, headless browsers and automation using 40+ behavioral signals plus server-verified SHA-256 proof-of-work.

* [Scrapfly Anti-bot Detector v2.8.4](https://github.com/scrapfly/Antibot-Detector) – Manifest V3 Chrome extension detecting CAPTCHAs, anti-bot systems, and browser fingerprinting in real time with confidence scores and capture tools.