Been working on a project for a while that I think might be interesting to people here from a technical standpoint.
The core idea is simple. Strava's relative effort metric is a really underused data point. Most apps just display it. I wanted to use it as the input for something more actionable, specifically adjusting daily nutrition targets based on what you actually did rather than a static guess.
So I built Velorific. It connects to Strava via the API, pulls the relative effort score after each activity, buckets the session into easy, moderate, hard or very hard using thresholds calibrated against real ride data, then sets macro targets accordingly. Carbohydrate targets follow the Burke et al ranges from the Journal of Sports Science. Protein sits at 1.6 to 1.8g per kg. The day after a very hard session the deficit gets waived entirely based on the IOC RED-S consensus guidelines.
From a technical perspective the most interesting challenge was calibrating the relative effort thresholds in a way that held up across different rider types, fitness levels and activity types. Happy to go into detail on that if anyone is curious.
The Strava webhook integration means targets update the moment a ride finishes which was important for the use case. Nobody wants to manually trigger a sync after every session.
App is live on iOS now. Would be genuinely interested in feedback from other developers who have built on the Strava API, particularly around relative effort and how others have approached using it as a meaningful signal rather than just a display metric.
