Available on the App Store · iOS

Know your peak.
Skip the crash.

Log a coffee and see how it plays out: when you'll be sharpest, when the crash is coming, and how late is too late for another cup.

Stimly Today screen with a live caffeine curve
Live Caffeine Curve Simulator
Adjust Dose: 200 mg
08:00 AM Dose
10:00 AM Peak
01:00 PM Half-Life
05:00 PM Metabolizing
11:00 PM Bedtime
Caffeine dose
160 mg
Peak Focus Window
9:36 AM
Crash Onset
2:36 PM
Bedtime Residual
Safe (13 mg)

How it works

  1. 1

    Take a short quiz

    Weight, age, and how coffee actually hits you. That tunes the curve to your body.

  2. 2

    Log your drinks

    From your favorites, our database, or a barcode scan. A cold brew sipped over two hours behaves differently than a quick espresso.

  3. 3

    Read your curve

    See when you're at your sharpest, when the crash starts, and how much caffeine will still be around at bedtime.

Free to start

Free Tier

Free
  • Personal caffeine curve, calculated live
  • Sleep readiness projection for tonight
  • Body Signals: Tag jitters, focus, or crashes directly on your curve
  • Daily limits & drink logging
PRO ENGINE

Stimly PRO

Optional Upgrade
  • Metabolic archetype calibration (8 biological models)
  • Tolerance reset insights & half-life tuning
  • Long-term energy trends & PDF Wellness Export

The core tracker and body signal logging are free forever. PRO unlocks advanced metabolic calibration and tolerance insights.

Stay in your sweet spot

Available on the App Store for iOS.