ReittiGPS - Reittiopas is a travel and navigation software developed by Essentia Solutions Oy for iPhone users. It helps users navigate the public transportation system in the Helsinki Metropolitan Area with ease. The app locates your current position and provides route suggestions to your desired destination.

ReittiGPS has over 5000 reviews with an impressive 4.5-star rating over the past 13 years. Users rave about its usefulness and convenience. The app offers a range of features, including automatic address completion, real-time vehicle location for route suggestions, departure reminders, arrival notifications, and stop alerts. It also displays real-time vehicle locations on a map and provides updates on any disruptions in the public transportation system.

The app is available in Finnish, Swedish, and English, and all features are included in the initial purchase price. However, it requires a functional internet connection and relies on the Helsinki Regional Transport Authority's (HSL) interface. The app also includes a feedback button in the settings menu for users to report any issues or suggest improvements.

Please note that continuous use of GPS in the background can significantly reduce battery life.