Raw HRV sparklines and gauges on your Apple Watch face
I'm Joel, solo dev. I built HRVSpark because I have AFib and the algorithmic HRV apps were giving me anxiety about my anxiety.
HRVSpark shows your raw SDNN values as live sparklines and gauges directly on your Apple Watch face — no readiness scores, no stress labels, no verdicts. Just your HealthKit data across four time windows (1H, 8H, 7D, 30D).
The hero 8-hour sparkline complication is free. $2.99 one-time Pro unlock. No subscription. No account. No cloud.
Built solo with SwiftUI + HealthKit + heavy AI pair programming.
My Apple Watch caught my AFib before a doctor did. After my ablation, I got curious about my HRV numbers and realized I just wanted to see the raw data — beautifully and at a glance — without an algorithm telling me how to feel. So I built it.
