MBTA Tracker is an application for smartwatches with circular displays running Tizen 2.3.2 or newer (Samsung Gear S2, Gear S3, Gear Sport, Galaxy Watch, and Galaxy Watch Active). It provides arrival-time predictions for nearby buses, subway lines, trolleys, and commuter rail lines operated by the MBTA, the Boston area's main public transit agency. The predictions are provided as a web service by the MBTA, and are based on real-time vehicle tracking data. The app also shows important MBTA alerts of interest to most riders (e.g. "Trains replaced by shuttle buses between Kendall and Park St. stations").

The app is written using HTML, CSS, and Javascript. I wrote it without using a framework, but I used a few open-source Javascript libraries, including the Hammer.js library, which I used to detect swipes on the watch screen, and the color-convert npm package, which I used to help me brighten some of the suggested colors provided by the MBTA in the data returned by their services.

Here are some screenshots from MBTA Tracker: