Every time an athlete uploads an activity to Strava, the server analyzes the activity and calculates various metrics for it. For each activity, the server calculates "elapsed time" (the time between the athlete starting the recording and ending it), and "moving time" (a measure of how long the athlete was actually moving). Moving time is then used to calculate additional statistics such as splits and pace data for runs.
At Strava, we strive to produce quality software to serve and motivate the world's athletes. As part of that mission, we are constantly updating and refining our user experience. And few things make for a worse user experience than the app crashing.
In March, we released the Strava 4.0 Android and iPhone Apps, which featured a completely redesigned Activity Feed. In order to bring the new design from a concept to a functional product, both platform teams went through several iterations of implementation and performance tuning. This post highlights some of the techniques we used along the way, obstacles we faced and limitations we discovered.