About RepStack

RepStack is a gym app that tells you what to do next. Not a spreadsheet. Not a social network. A tool that watches your sets, runs the math, and coaches you through every session — automatically.

Why We Built This

Most gym apps make you do the thinking. You log your sets, stare at a history screen, and figure out progression yourself. That's backwards. The app should handle the math so you can focus on lifting.

RepStack has a built-in rule engine that runs double progression, detects plateaus, and suggests deloads — all offline, all instant. When you're online, Claude AI adds personalized coaching on top.

What Makes It Different

• AI progressive overload — tells you the exact weight and reps for your next set
• Strength Score (0-999) — a single number measuring your total strength across 5 lifts
• What-If projections — see when you'll hit your next milestone, backed by real research
• Program import — paste text or upload XLSX, AI parses it in seconds
• 873 exercises with images — bundled on device, works offline
• Offline-first — SQLite on your phone, no account required, zero loading spinners

Built By

RepStack is an indie app built by a lifter who got tired of guessing what weight to put on the bar. Based in Europe.

Contact

Got feedback or questions? Reach out at [email protected].