{
 "schemaVersion": 1,
 "generated": "2026-10-30",
 "dataLicense": "CC BY-SA 4.0",
 "license": "CC BY-SA 4.0",
 "notice": "Data from Open Source Everything (https://opensourceeverything.org), licensed CC BY-SA 4.0: use it freely, credit the site, link to the page, and share changes under the same license. Listings were drafted with AI assistance and are managed by the r/TrueOpenSource moderators; check a project's own page before relying on a fact.",
 "id": "captcha",
 "name": "Bot protection and CAPTCHAs",
 "page": "https://opensourceeverything.org/g/captcha/",
 "category": "dev-blocks",
 "categoryName": "Building blocks for apps",
 "job": "Keeping bots and AI crawlers off a website",
 "closedApps": [
  "Google reCAPTCHA",
  "hCaptcha",
  "Cloudflare Turnstile"
 ],
 "coverage": null,
 "alternatives": [
  {
   "id": "cap",
   "name": "Cap",
   "page": "https://opensourceeverything.org/p/cap/",
   "summary": "Cap is a self-hosted tool that checks whether a visitor is a real person without showing puzzles or tracking them. It is for website owners who want to keep bots and AI crawlers off their sites.",
   "kind": "self_hosted",
   "setup": "advanced",
   "setupWhy": "You run it on your own server (a computer you set up and keep running), or from the command line.",
   "platforms": [
    "server"
   ],
   "license": "Apache-2.0",
   "licenseClass": "open",
   "licenseNeedsCheck": true,
   "stars": 8195,
   "forks": null,
   "status": "active",
   "verified": false,
   "latestRelease": null,
   "code": "https://github.com/tiagozip/cap",
   "website": null,
   "download": null,
   "release": null,
   "family": null,
   "familyChildren": [],
   "howToHelp": null,
   "project": "cap",
   "rank": 1,
   "fit": "full",
   "note": null,
   "why": "Does the whole job · Advanced setup",
   "score": 57.7
  },
  {
   "id": "anubis",
   "name": "Anubis",
   "page": "https://opensourceeverything.org/p/anubis/",
   "summary": "Anubis is a tool that sits in front of a website and blocks automated bots and AI scrapers that flood it with requests. It is meant for website operators, especially small sites, who cannot or will not use Cloudflare for protection.",
   "kind": "self_hosted",
   "setup": "advanced",
   "setupWhy": "You run it on your own server (a computer you set up and keep running), or from the command line.",
   "platforms": [
    "windows",
    "linux",
    "server"
   ],
   "license": "MIT",
   "licenseClass": "open",
   "licenseNeedsCheck": false,
   "stars": 23754,
   "forks": null,
   "status": "active",
   "verified": false,
   "latestRelease": null,
   "code": "https://github.com/TecharoHQ/anubis",
   "website": null,
   "download": null,
   "release": null,
   "family": null,
   "familyChildren": [],
   "howToHelp": null,
   "project": "anubis",
   "rank": 2,
   "fit": "partial",
   "note": "Blocks bots by checking connections, not by showing CAPTCHA puzzles; no CAPTCHA is described.",
   "why": "Does part of the job · Advanced setup",
   "score": 39.1
  },
  {
   "id": "mcaptcha",
   "name": "mCaptcha",
   "page": "https://opensourceeverything.org/p/mcaptcha/",
   "summary": "mCaptcha is a free system that checks whether a visitor is a person or a bot, without the image puzzles people usually have to solve. It is for website owners who want to keep bots and automated crawlers off their sites.",
   "kind": "self_hosted",
   "setup": "advanced",
   "setupWhy": "You run it on your own server (a computer you set up and keep running), or from the command line.",
   "platforms": [
    "server"
   ],
   "license": "AGPL-3.0",
   "licenseClass": "open",
   "licenseNeedsCheck": false,
   "stars": 2498,
   "forks": null,
   "status": "inactive",
   "verified": false,
   "latestRelease": null,
   "code": "https://github.com/mCaptcha/mCaptcha",
   "website": "https://mcaptcha.org",
   "download": null,
   "release": null,
   "family": null,
   "familyChildren": [],
   "howToHelp": null,
   "project": "mcaptcha",
   "rank": 3,
   "fit": "full",
   "note": null,
   "why": "Does the whole job · Advanced setup · No recent activity",
   "score": 34.2
  },
  {
   "id": "altcha",
   "name": "ALTCHA",
   "page": "https://opensourceeverything.org/p/altcha/",
   "summary": "A free code library and command-line tool that creates and checks small computing puzzles, which help tell real visitors apart from bots on a website. It is for programmers who build website protection.",
   "kind": "developer_tool",
   "setup": "advanced",
   "setupWhy": "Made for developers: you use it from code or the command line.",
   "platforms": [
    "windows",
    "mac",
    "linux",
    "server"
   ],
   "license": "MIT",
   "licenseClass": "open",
   "licenseNeedsCheck": true,
   "stars": 3,
   "forks": null,
   "status": "active",
   "verified": false,
   "latestRelease": null,
   "code": "https://github.com/altcha-org/altcha-lib-cpp",
   "website": "https://altcha.org",
   "download": null,
   "release": null,
   "family": null,
   "familyChildren": [],
   "howToHelp": null,
   "project": "altcha",
   "rank": 4,
   "fit": "partial",
   "note": "A developer library only; no ready-made visitor widget is described.",
   "why": "Does part of the job · Advanced setup",
   "score": 30
  }
 ],
 "source": "https://opensourceeverything.org/g/captcha/",
 "group": "Bot protection and CAPTCHAs",
 "replaces": [
  "Google reCAPTCHA",
  "hCaptcha",
  "Cloudflare Turnstile"
 ]
}