ALTCHA

BAU Software s.r.o.

Brno, Czech Republic

Application SecurityIdentity & AccessEmail SecurityNetwork Security

Serves Enterprise, Public Sector

Profile last updated: May 4, 2026

About

ALTCHA is a cybersecurity company based in Brno, Czech Republic working in application security, identity & access, email security +1 more.

ALTCHA provides privacy-first Captcha and bot protection for websites, apps and services. Its open-source core is a self-hosted proof-of-work Captcha that avoids cookies, tracking and third-party servers. ALTCHA Sentinel is a commercial, self-hosted adaptive bot and spam protection platform that uses multi-layered detection and machine learning to block automated threats while keeping the experience smooth for legitimate users. The solution is positioned for enterprises and government organisations that need compliance with GDPR, other global privacy laws and accessibility standards such as WCAG 2.2 AA and the European Accessibility Act.

Location

Brno, Czech Republic

Company type

Limited company

Legal name

BAU Software s.r.o.

VAT number

CZ19414480

Focus areas

captchabot protectionspam preventionproof-of-workprivacyaccessibilityopen sourceself-hosted

Languages

Services & products

Security domains

Application SecurityIdentity & AccessEmail SecurityNetwork Security

How they deliver

Software

Products

ALTCHA

Captcha and bot protection

Open-source, self-hosted, privacy-first Captcha using proof-of-work verification, with accessible audio challenges and no cookies or tracking.

ALTCHA Sentinel

Bot protection

Self-hosted, adaptive, machine learning-based bot and spam protection for websites, apps, forms, logins and APIs, with IP reputation, geo-fencing and proxy/TOR detection.