Cap – lightweight privacy-focused CAPTCHA

Cap is a lightweight CAPTCHA alternative intended to replace image-based challenges with automated techniques that place less burden on legitimate visitors.

It combines proof-of-work with browser instrumentation challenges rather than asking people to identify objects or transcribe distorted text. Cap is privacy focused and can be self-hosted, allowing website operators to run the CAPTCHA infrastructure themselves instead of sending visitor information to an external verification provider.

This is free and open source software.

Key Features

• Uses computational challenges together with browser instrumentation to distinguish legitimate clients from automated traffic.
• Offers a small client-side footprint with no external runtime dependencies.
• Does not send telemetry back to the Cap developers.
• Can run as a standalone self-hosted service with its own management and analytics facilities.
• Supports an invisible mode where verification can take place in the background without displaying the normal widget.
• Allows the appearance of the widget to be customised using CSS variables, including colours, dimensions, positioning and icons.
• Avoids the visual recognition puzzles commonly associated with traditional CAPTCHA services.
• Designed for straightforward integration into existing websites and applications.
• Provides a configurable server component which can be deployed independently of the protected application.
• Keeps verification infrastructure under the website operator’s control when deployed in standalone mode.

Website: github.com/tiagozip/cap
Support:
Developer: Tiago
License: Apache License 2.0

Cap is written in JavaScript. Learn JavaScript with our recommended free books and free tutorials.

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