PrivateCaptcha/PrivateCaptcha: Independent, privacy-first, self-hostable PoW CAPTCHA service made in EU

!GitHub go.mod Go version

Please refer to the official documentation.

Getting started

To spin up a local version of Private Captcha _for development_, clone this repository and run make run-docker in the root (it requires to have Docker installed). You can check Makefile for details of what it does exactly.

OpenAPI / Swagger

OpenAPI spec is available.

Project structure

├── cmd/                              Main executable of the server and few helpers
├── docker/                           Development-only docker files
├── docs/                             Developer documentation snippets
├── Makefile
├── pkg/                              Backend part of the project (API and Portal)
├── web/                              Frontend part of the project (Portal)
└── widget/                           Client-side widget code

Built with

• _Go_ for backend (API and Portal)
• _JavaScript_ (inevitably) for client widget, including WASM workers (where possible)
• _Postgres_ for "business" data (accounts, properties etc.)
• _ClickHouse_ for "operational" data (difficulty scaling, statistics etc.)
• TailwindCSS for Portal (backend)

Self-hosting

Self-hosting setup is in another repository and documentation - on main docs website.

Alternatives

Private Captcha is a private and open alternative to:

• Google reCAPTCHA
• hCaptcha
• CloudFlare Turnstile

Comparisons

DISCLAIMER: just like other similar tables, this reflects an author's opinion more than "legal reality"

Feature | Private Captcha | Friendly Captcha | Cap | Altcha | CloudFlare Turnstile | Google reCAPTCHA | hCAPTCHA --- | --- | --- | --- | --- | --- | --- | --- User-friendly | :white_check_mark: | :white_check_mark: | :white_check_mark: | :white_check_mark: | :white_check_mark: | :x: | :x: GDPR-compliant | :white_check_mark: | :white_check_mark: | :white_check_mark: | :white_check_mark: | :yellow_circle: | :yellow_circle: | :yellow_circle: Self-hostable | :white_check_mark: | :yellow_circle:* | :white_check_mark: | :white_check_mark: | :x: | :x: | :x: Difficulty scaling | :white_check_mark: | :white_check_mark: | :yellow_circle: | :white_check_mark: | :white_check_mark: | :yellow_circle: | :yellow_circle: High-throughput* | :white_check_mark: | :white_check_mark: | :x: | :x: | :white_check_mark: | :yellow_circle: | :yellow_circle: Sustainable* | :white_check_mark: | :white_check_mark: | :x: | :white_check_mark: | :white_check_mark: | :white_check_mark: | :white_check_mark:

NOTE: Friendly Captcha actually offers some kind of abandoned PHP implementation of static (no scaling) difficulty puzzles, but it's obviously unusable in real production

NOTE: "High-throughput" means low-latency backend (e.g. no Javascript on the backend, like in Cap and Altcha), profiled and optimized

NOTE: "Sustainable" means this project has means to survive (which, for example, in Google/CloudFlare case is "indefinitely" due to other kinds of revenue). Private Captcha, Altcha have a managed/SaaS offering that is fueling the development.

NOTE: reCAPTCHA and hCAPTCHA both self-declare to be GDPR-compliant, but since there was no court precedent to prove otherwise at the time of writing, they both collect excessive amounts of user tracking data.

License

This project is distributed under a PolyForm Noncommercial License (see LICENSE for more information). This allows you to self-host community edition of Private Captcha for non-commercial use. Commercial licenses available for enterprise edition - please contact us at [email protected]

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