Spring Boot Actuator provides several endpoints to monitor an application as:
/metrics
/b
Actually I wanted to do the same. But then I asked: why? To debug my service better which comes with a small performance penalty.
Just use a browser extension, like this one :) to get a view like this one
The "http.mappers" property works for me but I think you might need it camel cased ("jsonPrettyPrint").