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description: "Who builds Cap, the open-source, self-hosted CAPTCHA alternative: its maintainer, history, license, funding, and how to get in touch."
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# About Cap
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**TL;DR:** Cap is a free, open-source CAPTCHA alternative that replaces visual puzzles with proof-of-work and instrumentation challenges. It's licensed under Apache 2.0 and runs entirely on your own infrastructure, so visitor data never reaches a third party.
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## What is Cap?
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Cap is bot protection you can read, audit, and self-host:
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- A **~20 KB widget** that renders a single checkbox instead of image puzzles.
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- A **standalone server** that ships as one Docker container with a dashboard and multi-site-key support.
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-**Server libraries** (`@cap.js/server` and community ports) for verifying challenges in your own backend.
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- A **siteverify API compatible with reCAPTCHA and hCaptcha**, so migrating is mostly a URL swap.
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The full source lives at [github.com/tiagozip/cap](https://github.com/tiagozip/cap) under the [Apache 2.0 license](https://www.apache.org/licenses/LICENSE-2.0).
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## Why does Cap exist?
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Mainstream CAPTCHAs either interrogate users with puzzles or profile them with fingerprinting and risk scores, and both approaches route your visitors' data through a vendor. Cap takes a different position:
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-**Deterministic, not judgmental.** Every real user has a guaranteed path through; no classifier can silently reject someone for using a VPN or a privacy browser.
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-**Self-hosted, not rented.** Verification happens on your servers, which makes GDPR and CCPA answers simple. See [Compliance](./guide/compliance.md).
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-**Open, not promised.** Privacy claims are auditable because the code that makes decisions is public.
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## Get in touch
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- Bugs and feature requests: [GitHub issues](https://github.com/tiagozip/cap/issues)
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- Security reports and everything else: [hi@tiago.zip](mailto:hi@tiago.zip)
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