@fahd.elmazouni I’ve done things with standard appengine where a datastore post save hook also appends the necessary JSON to a daily GCS file destined for BigQuery.

This has worked well in the past. I did it for a contract a while ago. I don’t have a copy of the code but that should be enough to get you going. I could ask a colleague from that contract in a few days if they could give me code sample, or at least a more specific information for that recipe.

ping me again if this doesn’t help.