Service / system options for monitoring the operation of an application with external APIs?

Question

Notifications

There is a loaded application that works with payment gateways and other APIs.
You need to save requests, responses, time and other information. According to the saved data, you need to build reports and, in case of problems, notify (now zabbix is ​​doing this) .
There are about 100 application instances, data will be sent to the service over the network, preferably TCP, but not critical.
Now we are going to write our own, but I have a premonition that a similar task has already been solved and framed in a service / library / framework. It feels like you need something like zabbix on steroids and without a bias in network monitoring, customizable.
Advise solutions and best practices.
Thank you.

Answer 1

Can use www.fluentd.org to collect from the application.
Send metrics to your favorite monitoring, something like zabbix / graphite.
And "documents", depending on the number, should be sent either to mongu (capped collection?), Or to elasticsearch? And then analyze them.
Well, put some kind of broker between the application and ES \ mongo so that in case of failure of the receiving side, the data is not lost.