The tankerkoenig platform allows you to monitor the fuel prices with tankerkoenig.de from within Home Assistant and setup automations based on the information.
To use this sensor you need an API key from tankerkoenig. Go to tankerkoenig API and click on API-KEY in the top right, fill out the form and request a key. The API is free, but requests should be limited to less than once every 5 minutes.
Adding Tankerkoenig to your Home Assistant instance can be done via the user
interface, by using this My button:
Manual configuration steps
If the above My button doesn’t work, you can also perform the following steps
Follow the instruction on screen to complete the set up.
The Terms & Conditions of tankerkoenig.de specify that the API is not meant for massive data fetching, but it does not explicitly mention a limit. Having a maximum of 10 monitored fuel stations is recommended, and a warning will be issued otherwise.