Now I have been using the app: Grab, it’s a taxi app where you can either book a car or a moped (called motor in Indonesia). I really can recommend it, the driers are everywhere, my driver came in a minute. It’s cheap, a ride of 3km costed me ~0.7$. Because it’s booked as locals, the price is fixed. There are other local apps, that will do the same, but they are in Indonesian, so it can be complicated to use. I can recommend it.