I need to develop an internal application where the user of a source and up to 8 destinations, the best route is drawn on the map and show the distance in km. So based on that mileage the system calculates how much it would cost. I implemented this using the Google Maps API, but the application was limited to company then we would have to adiquirir a license. I want to know if the GraphHopper is free to use a company internally.
The GraphHopper routing engine is Open Source under the permissive Apache License and is therefor free to use for anything. You could even integrate it in your products, modify GraphHopper and sell this, without notice to us or contributing back. Although it is encouraged to contribute back so that your feature gets maintained for free by us. Also you can host GraphHopper on your own servers for 'free' and do whatever you want with it.
The GraphHopper Directions API that we host falls under our usage terms and always requires an API key. We decided to make it free for development purposes and Open Source projects, both with a limit of currently 500 queries per day. So, the free usage of the API in a company internally would not be allowed. But there are custom packages possible - see the current pricing here.