Your AI fasting coach
Say hello to Circa
Circa manages your fasting window automatically — adapting to your energy, mood, and cycle every single day. No timers. No logging. Just a 30-second check-in.
Tap any mood to see Circa react in real time
Fasting without the homework
Circa handles the protocol. You just answer three questions a day.
Step 01
Pick a start window
Tell Circa when you'd like to start fasting. 16:8, 18:6, 20:4 — she'll work with whatever fits your life.
Step 02
Check in daily
When your fast ends, you get one email: three sliders for energy, mood, and difficulty. 30 seconds total.
Step 03
Circa adapts
Based on your answers — and your cycle if you've enabled it — Circa adjusts tomorrow's window automatically.
Step 04
You just fast
No timers to start. No logging to do. Circa emails you when your fast begins and ends — that's it.
Ready to let Circa take over?
First fast is free. No credit card required.