Onyx: Fitness & AI Coach

Most fitness apps track. Onyx decides.

It reads how recovered you are this morning, then writes the workout to match. It knows what you ate, what you lifted last Tuesday, and what your sleep did to your HRV — and it uses all of it to tell you what to do today.

One app instead of four.


A COACH THAT KNOWS YOUR NUMBERS

Ask "why has my HRV been lower this week?" and get an answer about your Tuesday drinks and your 3pm espresso — not a Wikipedia paragraph. Coach reads your actual training history, food log, sleep and recovery. Ask it to build a session and it builds one you can start in a tap.

EATING OUT, SOLVED

Point your camera at the menu. Onyx reads it and ranks every dish against what you have left for the day — best pick first, with the one line that explains why it wins. No hunting a database for a restaurant that was never in it.

IT NOTICES BEFORE YOU DO

Resting heart rate creeping up, HRV down, breathing off your baseline — the signals that drift a day or two ahead of the sore throat. Onyx watches them and speaks up while there's still time to back off.

SESSIONS BUILT ON PURPOSE

Pick a focus and get a real session: the lift that deserves you fresh goes first, complementary angles follow, isolation finishes. Ask for arms and you get a triceps compound, a biceps compound, then long-head and lateral-head work.

A GOAL THAT CORRECTS ITSELF

Onyx measures your real maintenance calories as you log, and moves your target when your metabolism does. You don't recalculate anything.

YOUR BLOODWORK, READ

Snap your lab panel or import the PDF. Onyx pulls every biomarker, flags what's off, charts it over time, and tells you what it means for your training — low ferritin means less oxygen on board, so it eases your intensity until it comes back up. A heads-up, not a diagnosis.

WORKS WITH WHAT YOU ALREADY WEAR

Built on Apple Health. Apple Watch, Oura, Garmin, Fitbit — your pick. No hardware to buy, no subscription to a band. Onyx also has a full Apple Watch app that runs a whole session on your wrist with your phone in a locker.

EVERYTHING ELSE

• Sleep scored on depth, efficiency, consistency and breathing
• Cardio Load and training-load balance — are you ramping too fast?
• Food you can look into — additives, processing, real facts
• Form notes on all 213 movements
• Personal bests, streaks, and sending a workout to a friend
• Widgets, Lock Screen controls, Siri, and Live Activities
• Export everything as CSV, free. It's your data.

PRIVATE BY DEFAULT

Your health data stays on your phone unless you ask Coach a question. We never see your email. Sign in with Apple, or don't sign in at all.

Onyx Pro unlocks unlimited Coach, full illness early-warning, bloodwork analysis and Eating Out. Everything else is free, forever.

Onyx is not a medical device and does not diagnose anything.