I have many rest api(s) implemented in different spring boot applications, called by customers. There is common requirement to

1. Audit each customer request with outcome (success, no data, validation failed, unauthorized etc)
2. Ability to bill(or not bill) individual customers by sending daily aggregate counts and request types etc

Instead of implementing auditing (and billing out of it) in each Spring Boot App, thinking of developing a common generic "audit" service that can record in some storage (no sql) and do batch processing at end of day to generate billing data (and ignore non billable) for api calls during a day.

Tried designing common service to keep auditing and billing totally separate but so far they are getting mixed up per record. Is there a way to keep auditing and billing separate (avoiding billing info in audit record)?

Looking for ideas/suggestions?