Great tutorial, thank you!

There is a catch in using the API keys (https://cloud.google.com/docs/authentication/api-keys):

Note: Do not use API keys for local or production applications, except in the specific cases described below. For almost all cases, you should use service accounts.

The docs related to the GCP. I couldn’t find anything about OAuth integration between Firebase and Google API (e.g. Google Docs, Google Sheets, Google Drive,…).

Did you have a chance to publish this action or anything similar to that in production?