How to send score updates through push notifications?
Figure 13: Push notifications in Leaderboard

The database trigger or database change feed can be used to send push notifications to a player when the player’s score has been beaten by another player9. The database trigger can invoke the serverless function on ranking changes. The serverless function can write the ranking change data on the message queue for asynchronous processing and scalability. Bloom filter can be used to ensure that a player receives a notification on the ranking change only once by storing the player ID.