If you do not want to use more than the free App Engine quotas <https://cloud.google.com/free/>, it is recommended to set 'max_instances' = 1 for basic scaling <https://cloud.google.com/appengine/docs/standard/python/config/appref#scaling_elements>, as you currently have two instances running which will indeed exceed the free quota.
As for the excess requests and bandwidth, I am not sure where you are seeing these details, but it is recommended to add logging to your application code to ensure that you do not have any looping logic that is making excess API calls to Firebase. You can also use Stackdriver Logging <https://console.cloud.google.com/logs/viewer>to see how many actual requests were handled by your application. - Note that Google Groups is reserved for general product discussions and is not for technical support. If you confirm that you are not making that many requests, but end up being billed for it, it is recommended to open a free Billing support case <https://support.google.com/cloud/contact/cloud_platform_billing> with your additional detailed findings to have this properly investigated. -- You received this message because you are subscribed to the Google Groups "Google App Engine" group. To unsubscribe from this group and stop receiving emails from it, send an email to google-appengine+unsubscr...@googlegroups.com. To post to this group, send email to google-appengine@googlegroups.com. Visit this group at https://groups.google.com/group/google-appengine. To view this discussion on the web visit https://groups.google.com/d/msgid/google-appengine/8041b2f3-09ae-4d4e-b41c-ee38de31a6e5%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.