I have a client that for various reasons wants to be able to track events from all their internal apps by posting to a rest api application. These events are things like PurchaseMade with associated data such as price, customer, product_id, etc, or UserLoggedIn with the user_id and some extra contextual data, everything should be timestamped. These are not monitoring/performance metrics.

Anyway, I've been googling for open source tools/apps/software that already do this, but I can't seem to find anything that's applicable to this use case.

Could someone point me in the right direction or does anyone have any suggestions?

I'd be open software that could be purchases/licensed, the main thing is the collected data needs to hosted and controlled inside the company (i.e. no cloud provider/services).

Thanks in advance :)