RunnerUp is a free, open-source run tracker application for Android that allows users to track their running activities using the GPS on their phone. Developed by Jonas Oreland, this app is inspired by Garmin 410, RunKeeper, and EveryWhere Run. The app has no ads, no in-app purchases, and does not require user registration or tracking.

With RunnerUp, users can see detailed stats around their pace, distance, and time. The app also offers highly configurable audio cues to track stats and progress through headphones. Users can run free runs with target pace or target heart rate zone and easily configure and run effective interval workouts modeled after Garmin 410. Additionally, users can download and run workouts created at Garmin Connect and share their favorite workouts with friends.

RunnerUp supports heart rate monitoring using Bluetooth SMART (BLE), PolarWearLink, Zephyr, and ANT+ and allows users to configure and use heart rate zones. The app also supports automatic upload to various external applications such as Strava and Runalyze. Some external applications also support download and feed updates.

Overall, RunnerUp is an excellent run tracker app for Android that offers a range of features and functionalities for free. It also has a companion WearOS app bundled in the apk that must be installed manually.