altcha-org/altcha

Recursos principais

• 01Background proof-of-work challenge that avoids visual puzzles.
• 02Cookie-free and fingerprint-free, with no tracking.
• 03Argon2id and Scrypt algorithms that resist ASIC and GPU acceleration.
• 04Image code-challenge fallback with audio support.
• 05Multiple display modes and themes for the widget.
• 06Server libraries in many languages and framework starter templates.

Casos de uso

• Protecting contact, signup and login forms from spam bots without tracking users.
• Adding bot and abuse protection to APIs or comment systems while meeting GDPR and accessibility requirements.
• Running a fully self-hosted anti-spam layer with no dependency on third-party CAPTCHA services.

Tópicos

Perguntas frequentes

O que é altcha?

Self-hosted, cookie-free CAPTCHA alternative that uses a proof-of-work challenge to block spam and bots, with WCAG 2.2 AA accessibility.

altcha é gratuito? Qual é a licença?

altcha é open source sob a licença MIT. Confira os termos da licença antes de usá-lo em produtos comerciais.

altcha ainda é mantido?

Manutenção ativa. O último commit de altcha foi em 19 de out. de 2026.

Para que posso usar altcha?

Protecting contact, signup and login forms from spam bots without tracking users. Adding bot and abuse protection to APIs or comment systems while meeting GDPR and accessibility requirements. Running a fully self-hosted anti-spam layer with no dependency on third-party CAPTCHA services.

Onde consigo altcha?

O código-fonte e as instruções de instalação estão no GitHub: https://github.com/altcha-org/altcha