Cap

Cap at a glance

Cap is a lightweight, open-source alternative to services such as reCAPTCHA or hCaptcha. Instead of image puzzles, Cap gives the browser a proof-of-work task and adds unobtrusive behavioural checks to tell automated requests apart from real users. For administrators, the bundled standalone server is the interesting part: it runs as a small Docker container and works without external dependencies or telemetry.

The project is organised as a monorepo, with the self-hosted server and the client-side widget library released separately. For an update radar, the standalone server is what matters, and its output appears as its own release line.

When updating, it helps to distinguish server releases from widget releases, since the two follow different version lines. Before switching, it is worth reviewing possible changes to configuration and API behaviour so that bot protection on existing forms keeps running without interruption.