Proof of Work
Proof of Work (PoW) is an invisible challenge where the browser solves a computational puzzle.
How It Works
When a PoW challenge is triggered, the browser performs a series of hash computations in the background. The user doesn't see or feel anything — it takes 50–500ms depending on the difficulty level.
Why It Works Against Bots
Every request costs CPU time. A human submitting one form barely notices the delay. A bot trying to submit thousands of forms is significantly slowed down because each submission requires real computation.
Fully Accessible
PoW requires no visual interaction — it's completely invisible and runs automatically. This makes it ideal for users with disabilities.
Fallback
If the browser cannot complete the PoW challenge (e.g., very old browser or JavaScript disabled), the Math CAPTCHA is shown as a fallback.