About the openelevationservice category

If you have any questions about openelevationservice, which data is being used or how to use the service please place them here.

The GIScience/openelevationservice project on github states:

You can also use our free API_…:

…but nowhere am I finding information about how one can obtain the API keys. Could somebody please point me to the right place?

https://openrouteservice.org/dev/#/signup