Is there an alternative to Google Maps to find GPS coordinates of a place in Germany?
There are a number of APIs for OpenStreetmap, e.g. via html request: 

https://nominatim.openstreetmap.org/search?q=pleikartsförsterstrasse,%20heidelberg&amp;format=json&amp;polygon=1&amp;addressdetails=1


A json is returned. You can easily access the type of information you need.