Jarvis - Your runs decoded

Every run hides your next record.

Most running apps only check your pace at fixed kilometer splits. Jarvis goes deeper. Using a sliding-window algorithm, it scans every segment of every run — finding your fastest 5K buried inside a 10K training run, or your best 400m from that final kick.

14 distances. One dashboard.
Track personal bests from 100m sprints all the way to the Marathon. Tap any record to see the exact GPS route on a map, with the PR segment highlighted in green.

Race predictions grounded in science, not guesswork.
Forget generic calculators. Jarvis builds a personalized fatigue profile from your actual performances and applies a 4-step prediction engine:

• Personalized fatigue exponent — Are you a speed runner or an endurance runner? Jarvis computes your unique curve instead of using a one-size-fits-all formula.
• Effort-weighted training load (ACWR) — Understands the difference between a recovery jog and a tempo run.
• Taper detection (TSB) — Trained hard then rested? Jarvis recognizes you're peaking and adjusts your prediction.
• Durability check — Flags when your speed is ready for a marathon but your longest run says otherwise.

100% private. Zero servers.
All analysis happens entirely on your iPhone. Your health data never leaves your device — no accounts, no cloud, no tracking.