Sum
Arithmetic with operand count and operators tied to difficulty
One edition, one defined method
Widget methods and service engines have different roles
Visible PoW
Visible computation with 1, 3 or 6 rounds
Marks
Ordered symbols with more choices at higher difficulty
Invisible PoW
Invisible work on the protected action, without a visual challenge
Advanced Marks
Compound marks with near matches
Service engines
The project contains adapters for Cap, ALTCHA, GoCaptcha, Mosparo, IconCaptcha, Wicketkeeper, FCaptcha, Prosopo, Captcha Pro, mCaptcha and Digital Captcha An adapter does not establish deployment readiness or independent demo availability
Evaluate real methods