Building for the smallest niche in fitness

Grip strength has an obsessive audience — grip sport, climbing, grappling, hand rehab — and almost no software built for it. Generic gym trackers treat a timed dead hang and a set of curls as the same object, which falls apart the second you care about left vs. right hand, a hold measured in seconds, or a dynamometer reading.

So I built MrGripper. First commit April 2025, on the App Store six weeks later. It's now at v1.9.1: per-hand sets, hold timers, dynamometer tests, a guided workout flow, Live Activities on the Lock Screen, and PRs scoped by exercise, equipment, load, and hand. Offline-first, no account, native iOS. Four languages across 19 storefronts.

The bet is that a small audience who cares intensely beats a large one that's mildly interested. Grip athletes track their numbers obsessively — they just do it in the Notes app, because nothing else understands what they're measuring.

The hardest part hasn't been the app. It's reaching a niche this specific — the people who'd pay for it are scattered across climbing gyms, grip-sport forums, and rehab clinics, not anywhere I can buy an ad.

Anyone here selling into a niche this narrow? What actually worked for finding your first users?