Most workout apps are bloated. You're between sets, sweaty, 45 seconds on your rest timer, and the app wants you to tap through menus, scroll through exercise lists, and confirm things you've already confirmed.

So I built OpenTrainer. A free, open source workout tracker that remembers what you lifted last time and suggests what to do next. Accept with one tap, use the simple interface to make adjustments.

Here's a few things other apps weren't doing that I wanted:

Smart defaults. Pre-filled weight/reps based on your last session with progression suggestions

Thoughtful AI. Generate routines based on your equipment, suggests exercise swaps mid-workout, weekly performance insights

Data ownership. Full JSON export. No lock-in

Privacy first. No tracking pixels, no selling your data

Open source

Tech stack: Next.js 16, Convex, Clerk, OpenRouter, Tailwind, shadcn

It supports lifting, cardio, and mobility. Looking for feedback from people who are looking for something different.

Sign up during the Alpha and keep Pro free forever.

opentrainer.app