Overview

GDPR, WCAG 2.2 AA, and EAA compliant, self-hosted CAPTCHA alternative with PoW mechanism. ALTCHA is a next-gen Captcha and bot protection solution for websites and apps, designed for privacy, accessibility, and compliance. The project has 2K+ GitHub stars and is licensed under MIT.

Key Features

Source: GitHub README

Frictionless Experience: Uses proof-of-work (PoW) instead of visual puzzles for a seamless user experience.
Code Challenge (New in v2): Supports accessible code challenges (“enter code from image”) with an audio option.
Cookie-Free Design: GDPR-compliant by default—no cookies or tracking.
Fully Accessible: Meets WCAG 2.2 AA-level standards and complies with the European Accessibility Act (EAA).
Lightweight: Minimal bundle size for fast page loads and optimal performance.
Self-Hosted: No dependency on third-party services.

Getting Started

Source: GitHub README

npm install altcha

import 'altcha';

Normalized Features

Source: tool-features-normalized.json

accessibility, mobile app, npm, plugins, privacy focused, rest api.

Deploy

Docker

Self-host with Docker Compose

Coolify

One-click via Coolify panel

Elestio

Managed hosting from $9/mo

PikaPods

Simple managed hosting

Features

Integrations & APIs

Plugin / Extension System
REST API

Security & Privacy

Privacy-Focused

Localization & Accessibility

Accessibility (a11y)

Mobile & Desktop

Mobile App

Replaces

Related Security & Authentication Tools

View all 159 →

Ghidra

66K

A free, open-source software reverse engineering framework created by the NSA — disassemble, decompile, and analyze compiled code on any platform.

security Apache-2.0

PocketBase

58K

Open-source backend in a single 12 MB binary — realtime database, auth, file storage, and admin dashboard. No Docker, no Postgres, just run it.

security MIT Easy to deploy

Vaultwarden

57K

Lightweight, self-hosted Bitwarden-compatible password manager written in Rust. Uses 10x less RAM than the official server and works with all Bitwarden clients.

security AGPL-3.0

Zen Browser

41K

Zen Browser is a privacy-focused, beautifully designed Firefox fork with a unique sidebar tab layout, split views, and built-in content blocking — no telemetry, no tracking.

security MPL-2.0