Open-source alternatives guide · Updated 2026
Compare the best free and open-source alternatives to Cloudflare Turnstile — 6 verified projects with explicit catalog relationships. Inspect licenses, GitHub activity, self-hosting signals, and migration fit before you switch.
Only explicit alternative relationships are shown—never inferred competitor claims.
This guide compares 6 verified open-source alternatives to Cloudflare Turnstile, including Cap, ALTCHA, mCaptcha, and Procaptcha.
Projects appear across Security & Privacy and Infrastructure. 4 options include a self-hosting signal — see the self-hosted catalog. Ranking follows public GitHub stars and recorded momentum—not vendor marketing. Compare projects side by side, then confirm license fit, migration effort, and operational ownership before adopting any option.
Strongest repository-activity signal: Cap · Jump to ranking · 7.3K stars · self-hostable
Proprietary product with documented open-source alternatives cataloged on OpenSourceChoice. Compare licenses, repository activity, and self-hosting options befo
Compare capabilities, licensing, and ownership model. Stars help with discovery; they are not a security or product-fit guarantee.
Open-source alternative to Cloudflare Turnstile
Free, open-source and self-hosted CAPTCHA alternative to reCAPTCHA. Privacy-first and powered by proof-of-work and instrumentation challenges.
Free, open-source and self-hosted CAPTCHA alternative to reCAPTCHA. Privacy-first and powered by proof-of-work and instrumentation challenges. Review the official repository, licen
Open-source alternative to Cloudflare Turnstile
GDPR, WCAG 2.2 AA, and EAA compliant, self-hosted CAPTCHA alternative with PoW mechanism.
GDPR, WCAG 2.2 AA, and EAA compliant, self-hosted CAPTCHA alternative with PoW mechanism. Review the official repository, license, release activity, and deployment documentation be
Open-source alternative to Cloudflare Turnstile
A no-nonsense CAPTCHA system with seamless UX | Backend component
A no-nonsense CAPTCHA system with seamless UX | Backend component Review the official repository, license, release activity, and deployment documentation before production adoption
Open-source alternative to Cloudflare Turnstile
Open-source, frictionless CAPTCHA and bot defense. A privacy-focused alternative to reCAPTCHA and hCaptcha.
Open-source, frictionless CAPTCHA and bot defense. A privacy-focused alternative to reCAPTCHA and hCaptcha. Review the official repository, license, release activity, and deploymen
Open-source alternative to Cloudflare Turnstile
Independent, privacy-first, self-hostable PoW CAPTCHA service made in EU
Independent, privacy-first, self-hostable PoW CAPTCHA service made in EU Review the official repository, license, release activity, and deployment documentation before production a
Open-source alternative to Cloudflare Turnstile
The SDK that is used to integrate Friendly Captcha v2 into your website. Protect your websites and online services from spam and abuse with Friendly Captcha, the privacy-first anti-bot solution.
The SDK that is used to integrate Friendly Captcha v2 into your website. Protect your websites and online services from spam and abuse with Friendly Captcha, the privacy-first anti
Map must-have capabilitiesList the workflows in Cloudflare Turnstile you cannot drop during migration.
Verify the licenseConfirm it fits your use, distribution, and compliance model. Browse license briefs.
Run a proof of conceptTest real data, integrations, clients, and failure modes. Use Compare for side-by-side checks.
Plan ownershipAssess upgrades, backups, support, and an exit path. Read when self-hosting is worth it.
OpenSourceChoice currently lists 6 projects with an explicit alternative relationship to Cloudflare Turnstile. Catalog highlights include Cap, ALTCHA, and mCaptcha. Rankings follow public GitHub stars and recorded momentum—not paid placement. Match capabilities and license fit to your workflow before adopting any option.
Most catalogued alternatives publish source under OSI or source-available licenses and are free to inspect. Hosting, commercial support, or cloud model APIs may still cost money. Always read the project license for your use case.
4 options in this list carry a self-hosting signal. Confirm the official install guide, backups, upgrades, and hardening steps before production.
Map must-have Cloudflare Turnstile workflows, verify license and compliance fit, run a proof of concept with real data and integrations, then plan ownership for upgrades, backups, support, and an exit path.
Narrow the same alternatives by search, license, tags, or self-hosting signals when you need a tighter shortlist.
Free, open-source and self-hosted CAPTCHA alternative to reCAPTCHA. Privacy-first and powered by proof-of-work and instrumentation challenges.
Security & PrivacyOpen-source projects grouped in this category for discovery and comparison.#
JavaScriptProjects tagged with this topic in the verified catalog.
Github ActionsProjects tagged with this topic in the verified catalog.
NodeJSProjects tagged with this topic in the verified catalog.
Self-hostedThis project carries a self-hosting or local-deployment signal. Verify the official install guide before production use.Cloudflare TurnstileProprietary product with documented open-source alternatives cataloged on OpenSourceChoice. Compare licenses, reposit…GDPR, WCAG 2.2 AA, and EAA compliant, self-hosted CAPTCHA alternative with PoW mechanism.
InfrastructureOpen-source projects grouped in this category for discovery and comparison.#
TypeScriptProjects tagged with this topic in the verified catalog.Github ActionsProjects tagged with this topic in the verified catalog.JavaScriptProjects tagged with this topic in the verified catalog.Self-hostedThis project carries a self-hosting or local-deployment signal. Verify the official install guide before production use.Cloudflare TurnstileProprietary product with documented open-source alternatives cataloged on OpenSourceChoice. Compare licenses, reposit…A no-nonsense CAPTCHA system with seamless UX | Backend component
Security & PrivacyOpen-source projects grouped in this category for discovery and comparison.#
RustProjects tagged with this topic in the verified catalog.Github ActionsProjects tagged with this topic in the verified catalog.JavaScriptProjects tagged with this topic in the verified catalog.Self-hostedThis project carries a self-hosting or local-deployment signal. Verify the official install guide before production use.Cloudflare TurnstileProprietary product with documented open-source alternatives cataloged on OpenSourceChoice. Compare licenses, reposit…Open-source, frictionless CAPTCHA and bot defense. A privacy-focused alternative to reCAPTCHA and hCaptcha.
Security & PrivacyOpen-source projects grouped in this category for discovery and comparison.#TypeScriptProjects tagged with this topic in the verified catalog.Github ActionsProjects tagged with this topic in the verified catalog.JavaScriptProjects tagged with this topic in the verified catalog.Cloudflare TurnstileProprietary product with documented open-source alternatives cataloged on OpenSourceChoice. Compare licenses, reposit…Independent, privacy-first, self-hostable PoW CAPTCHA service made in EU
Security & PrivacyOpen-source projects grouped in this category for discovery and comparison.#
GoProjects tagged with this topic in the verified catalog.Github ActionsProjects tagged with this topic in the verified catalog.JavaScriptProjects tagged with this topic in the verified catalog.Self-hostedThis project carries a self-hosting or local-deployment signal. Verify the official install guide before production use.Cloudflare TurnstileProprietary product with documented open-source alternatives cataloged on OpenSourceChoice. Compare licenses, reposit…The SDK that is used to integrate Friendly Captcha v2 into your website. Protect your websites and online services from spam and abuse with Friendly Captcha, the privacy-first anti-bot solution.
Security & PrivacyOpen-source projects grouped in this category for discovery and comparison.#TypeScriptProjects tagged with this topic in the verified catalog.Github ActionsProjects tagged with this topic in the verified catalog.JavaScriptProjects tagged with this topic in the verified catalog.Cloudflare TurnstileProprietary product with documented open-source alternatives cataloged on OpenSourceChoice. Compare licenses, reposit…
CA
AL
MC
PR
PR
FR