Allow the user_id field of the create_notification mutation to accept an array of integers so its type is: Int! | [Int!] instead of just Int!.
This would allow us to submit a batch of notifications in a single call, rather than needing to make many API calls when there are multiple recipients.
This may reduce the API complexity (say 30000 base + 10 for each recipient?) as well as load on the API servers. Plus eliminate a minor inconvenience of having to loop all of the recipients .
My suspicion is that the internal notification system is already built to handle multiple users in a single submission as notifying all people in a column, subscribers, teams, etc. entails notifying multiple people. I could be wrong, but I’m thinking as if I were the person developing the internal notification service - that’s what I’d have done to support multiples.