We use all and any tools and technology suitable for the job. Currently we are using NodeJS for bot and API server in Typescript language. We use Neo4J database for bus routing, MongoDB for session and MySQL database for everything else, including geospatial search. Machining learning services are used to predict the taxi fare. We use Java-based open source software for collecting data from GPS devices. Currently we are using an open source Android app, which uses webview UI 🙂 We are planning to go native using Google Map.
Most of our websites are static web pages hosted in Firebase. We use Facebook authentication and our JSON API and Firebase real-time database to obtain the data.