MyFit is a workout tracker built around the same progressive overload and RIR-based training philosophy as the RP Hypertrophy app. I've rebuilt it three times now, v2 alone was pulling 10,000+ views a month before I scrapped it, because each version's foundation couldn't hold up whatever I wanted to build next.

v3 is the one I'm actually proud of. It moved off MongoDB and REST onto Prisma with PostgreSQL and tRPC for type safety across the whole stack, and Svelte 5 with runes for the UI. The rewrite took way longer than I promised, mostly because I forced myself to slow down after watching the v2 codebase rot under real usage. It shipped with a one-click migration tool so existing users didn't lose their workout history moving over.

Some of what it actually does: progression formulas that adjust your next workout based on logged reps, load, and RIR, changing your split mid-mesocycle without losing history, and drag-and-drop exercise reordering people had been asking for since v1.

It's also survived a real production incident. I once dropped a few columns on the wrong CockroachDB cluster and put the whole database into a multi-day read-only lockout, mid-way through a MOBA match with friends, no less.

I've written a lot more about this project than any other, if you want the full story: Building MyFit v3, Suboptimal, MyFit V3 is Live, and When I Broke Prod.