WinilooC is THE modern, fast and smart search for the nearest filling station or public toilet.
The app supports you with optional directions for you chosen toilet or filling station. Each place has an overview of the some equipment features (e.g. fees and wheelchair accessibility) to find the appropriate toilet or gas station for you.
At the moment there are 170,000 listed toilets from OpenStreetMap.
The German filling station price data is served by the "Markttransparenzstelle für Kraftstoffe" via "Tankerkönig" under CC-BY 4.0 license.