STAR is the official application of the STAR network of Rennes Métropole, designed to help you move around the city with ease. The app provides you with all the necessary information about the public transport network, including bus, metro, bike, and carpooling.

One of the most useful features of the app is the real-time traffic alerts, which keep you informed about any disruptions or deviations on your route. You can also follow the traffic updates on Twitter and receive push notifications when there are disruptions on your favorite lines. The app also provides you with the real-time schedules of the buses and metros, and you can plan your journey with ease using the geolocation feature.

The e-boutique feature allows you to purchase your transport tickets online without having to wait in long queues. You can also search for your journey by selecting your departure and arrival locations, as well as your mode of transport. The app provides you with various options for your journey, including the time of transport and the number of connections.

Overall, STAR is a must-have app for anyone living in or visiting Rennes. It is a comprehensive guide to the city's public transport network and provides you with all the necessary information to move around the city with ease.