What are API Calls?
Besides monitoring real user experience in browser, Plumbr server-side agents are designed to monitor the APIs published on the server-side. Currently Plumbr supports APIs running on Java Virtual Machines (JVMs).
The API call is monitored from the moment it arrives to the JVM boundary until the response is sent to the caller. The API call duration and its outcome are registered similar to the user interactions, making it possible to expose the performance and availability of the API.
Note that in case a Plumbr Agent was already present in the upstream, the JVM processing the request is linked with the ongoing user interaction or API Call. The outcome of this approach is a distributed trace throughout all the nodes, providing end-to-end transparency of a call throughout the infrastructure.
Additional server-side monitoring increases the transparency, as slow or failed interactions are now traced to all server-side nodes to more precisely capture the evidence needed for solving the potential error or bottleneck.
That being said, we strongly recommend to start monitoring the real user experience first by adopting our Browser Agent and adding the server-side monitoring during the second phase of adoption. Without understanding the true user experience, exposed insights from the server-side are missing the proper context and making it hard to make informed decisions.