hCaptcha - Do you use a captcha to keep out bots? hCaptcha is a drop-in replacement for reCAPTCHA that earns website owners money and helps companies get their data labeled.
reCAPTCHA - reCAPTCHA is a free security service that protects your websites from spam and abuse.
GeeTest CAPTCHA - GeeTest protects your websites, mobile Apps and APIs from bot threats.
Prosopo.io - Protect your applications from bots with Procaptcha. GDPR compliant, privacy friendly, open source, and better value than alternatives. Switch from reCAPTCHA in minutes.
DataDome - DataDome provides innovative technology and human expertise to block bad bots.
ALTCHA - ALTCHA is a free CAPTCHA alternative that uses a proof-of-work mechanism to protect your website, and online services from spam.