Hi Louise,
You’re right, as stated per the Transactions and Entity Groups documentation <https://cloud.google.com/datastore/docs/concepts/transactions#transactions_and_entity_groups>, there is a 25 entity groups limit for a single data transaction. However, according to your description this error should not happen and there should be no need of using Cross-Group (XG) Transactions either. Still, it is possible that this error is triggered by something else as the way your entities were defined. Can you provide a Minimal Working Example <https://en.wikipedia.org/wiki/Minimal_Working_Example> of your code including the transaction and a snippet of how you defined your entities? In fact, this would help to better visualize the root cause of your error and provide you with answer on how to solve it. Regards, Alex -- 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/9d86c3b2-c1d1-4b55-adf2-581affeb9ec6%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.