Hi everyone. I’m getting close to launching a fitness app I’ve been building called Athalyze, and I’d really appreciate candid feedback as I’m finalizing things.
Overview video: https://youtu.be/FPYwbLAIGHE?si=VpLP07QeBA0mp52y
Athalyze exists because it’s something I personally wanted to use. My goal wasn’t mass-market simplicity. It was to build a platform that treats fitness data seriously, especially for athletes who train with multiple devices and care about data integrity. That said, I’ve tried to keep the UI clean and approachable so it’s still usable without being overwhelming.
A few core design decisions that shape the app:
• Multi-source data shown together - If you wear a Garmin, Apple Watch, Oura, or Whoop, you can view metrics like HRV from all of them on the same graph and see how they compare.
• Automatic merging of multi-device recordings - When the same workout is recorded on multiple devices, for example a watch and a bike computer during a triathlon, Athalyze automatically combines those recordings into a single activity. The best data is selected per metric, all source data is preserved, and duplicate workouts never inflate your stats.
• Source-aware analysis - You can see where data comes from, compare devices directly, and explore advanced metrics like raw R-R interval data and Garmin FIT developer fields.
• Consistent experience across platforms - The web app and mobile apps share nearly identical functionality unless there’s a device-specific reason not to.
• Athlete-focused extras - Histogram views for analyzing training distribution over time, device history with battery state tracking, native iOS widgets, and detailed outdoor maps including 3D.
Athalyze is currently available in early access:
• Web: https://www.athalyze.com
• iOS and macOS via TestFlight: Join the Athalyze beta - TestFlight - Apple
I’m very open to feedback and would love to know your thoughts.
Thanks for taking a look.
Disclaimer: Athalyze is free to use during early access, with a freemium model planned longer term. This is another thing I would love feedback on, what features you think would make sense to have behind a paywall and what you would be willing to pay for a tool like this.