The databaseURL for Cloud Firestore is no longer listed in either the Firebase or Google Cloud consoles, so the last step was a bit confusing for me. Instead of generating a URL for the database, Google now has an API endpoint at
https://firestore.googleapis.com/v1/projects/[project-id]/databases/(default)/—this worked for me as the databaseURL in the very last step. Here’s the documentation from Google.
[project-id] is the text id, not the numeric one, so something like
(default) is actually the name of the database, and you really do include the parentheses.