SaaS Alternative

reCAPTCHA hCaptcha







Developer links


Say goodbye to those pesky picture puzzles and hello to mCaptcha, the silent guardian of user privacy in the captcha universe! This nifty tool is like a ninja, working behind the scenes with its proof-of-work magic to keep your website safe without making a peep. It's the digital equivalent of a bouncer who doesn't need to know your life story to let you into the club. No tracking, no profiling, just pure, unadulterated privacy. Perfect for the privacy-savvy user who's tired of being stalked by traditional captchas. And for those of you playing hide and seek behind a NAT, mCaptcha's got your back, no IP address needed. It's like having an invisible shield that only costs attackers a fortune to mess with, while costing you peanuts to host on RepoCloud. Plus, it's the open-source hero we've all been waiting for, with client libraries dressed in the most stylish proprietary-friendly licenses. Want to switch from reCAPTCHA or hCaptcha without breaking a sweat? mCaptcha is your go-to, plug-and-play champion. At its core, mCaptcha flexes its SHA256 muscles to hand out tokens like candy on Halloween, ensuring only the good guys get through. Host it on RepoCloud, and watch your hosting bills shrink like cotton in hot water!



  • Privacy Focused
  • mCaptcha is a proof-of-work based captcha system that prioritizes your privacy. It doesn't track or profile your users, ensuring a secure and private user experience.
  • Robust and Accurate
  • Whether your users are behind NATs or not, mCaptcha provides a seamless experience. It doesn't use IP addresses for rate-limiting, making it a reliable and accurate system.
  • Best-in-class User Experience
  • mCaptcha is designed to be unobtrusive. Your users won't even notice it's there. No more annoying images or unnecessary tasks.
  • Defend Like Castles
  • mCaptcha's proof-of-work based solution defends your site fiercely, making attacking your site more expensive than what it will take for you to respond to the attacker's requests.
  • Libre Software
  • mCaptcha is a free software. It's client libraries are licensed using proprietary-friendly free software licenses but the core is AGPL'd.


  • Proof-of-Work Based
  • mCaptcha uses SHA256 based proof-of-work (PoW) to rate limit users. This makes interacting with websites (computationally) expensive for the user, deterring malicious attacks.
  • Automated Process
  • The entire process is automated from the user's point of view. All they have to do is click on a button to initiate the process.
  • Resistant to Replay Attacks
  • mCaptcha's proof-of-work configurations have short lifetimes and can be used only once. This makes it resistant to replay attacks.
  • Seamless User Experience
  • mCaptcha's user experience is super silent. Solving CAPTCHAs has never been easier. One click and your users are on their way.
  • Compatible with reCAPTCHA and hCaptcha
  • Already using a captcha solution? No worries, mCaptcha's APIs are compatible with reCAPTCHA and hCaptcha!