Lightweight, modern open-source CAPTCHA alternative designed using SHA-256 proof-of-work.
Portugal
EU
Private Captcha AlternativesAnti-Spam Tools and other similar apps like Private Captcha
Private Captcha is described as 'Independent, privacy-first, self-hostable Proof-of-Work CAPTCHA service made in EU. Instead of asking users to solve complex puzzles or track their behavior, Private Captcha solves an invisible cryptographic task in the background' and is a Anti-Spam tool in the security & privacy category. There are more than 10 alternatives to Private Captcha for a variety of platforms, including Web-based, SaaS, Self-Hosted, Wordpress and JavaScript apps. The best Private Captcha alternative is Cap Captcha, which is both free and Open Source. Other great apps like Private Captcha are Anubis, reCAPTCHA, Procaptcha and Forget Spam Comment.
Alternatives list
48 Anubis alternativesApplies sha256 proof-of-work challenges to incoming HTTP requests, targeting AI crawlers, bots that ignore robots.txt, and automated scrapers, protecting server resources and preventing unwanted search engine indexing for privacy-focused sites.
Cost / License
- Free Personal
- Open Source (MIT)
Application type
Platforms
- Self-Hosted
- Go (Programming Language)
- Docker
28 reCAPTCHA alternativesreCAPTCHA is a free service that protects your site from spam and abuse, using risk analysis techniques to tell humans and bots apart.
Prosopo Procaptcha redefines user verification with a unique approach that emphasizes privacy and security. It's a pioneering solution designed to offer an alternative to conventional CAPTCHA systems that often compromise user privacy.
Cost / License
- Freemium
- Open Source (Apache-2.0)
Application type
Platforms
- Online
- Software as a Service (SaaS)
- Wordpress
+3
A lightweight (~217 bytes vanila JS at frontend) and privacy-friendly plugin to prevent spam comment in the default commenting system of WordPress. Works instantly. No settings required. No captcha.
19 Cloudflare Turnstile alternativesTurnstile is Cloudflare's smart CAPTCHA alternative. It automatically chooses from a rotating suite of non-intrusive browser challenges based on telemetry and client behavior exhibited during a session.
Cost / License
- Free
- Proprietary
Platforms
- Online
- JavaScript
- Software as a Service (SaaS)
18 ALTCHA alternativesALTCHA is a privacy-first solution built to help developers and website owners stop bots, spam, and automated abuse — without making things harder for real users. It replaces traditional CAPTCHA systems with a smarter, quieter approach to verification and threat detection.
DataDome is the only bot protection solution delivered as-a-service. Unlike competing products, it requires no architecture changes or DNS rerouting, and will never be a single point of failure.
Cost / License
- Paid
- Proprietary
Application type
Platforms
- Windows
- Linux
- Software as a Service (SaaS)
The Arkose Labs platform undermines the economic drivers behind fraud until perpetrators are compelled to abandon attacks. Real-time risk classification of traffic with interactive enforcement challenges, the solution defeats automated attacks...
Cost / License
- Paid
- Proprietary
Platforms
- Software as a Service (SaaS)
Canada
United States
United Kingdom
Czechia
France
India
