Kafka's pretty neat and 'everyone' uses it. But for small scale stuff, this is easy enough to do with a queue, a timer (maybe even cron) and a small SQL DB (SQL

Kafka's pretty neat and 'everyone' uses it. But for small scale stuff, this is easy enough to do with a queue, a timer (maybe even cron) and a small SQL DB (SQLite, H2, Etc.). Msgs flow into queue. Repeating timer wakes up, runs script/program to: create temp table in DB, dump queue to temp table, query temp table, write query results wherever, drop temp table. You can add further features/complexity by adding sliding/tumbling window, coalescing queue or other parts into the mix, per your specific requirements.