Datadog Automatic APM instrumentation is generally sufficient for most customers, but as soon as it’s not there can be a pretty significant engineering burden. An engineer will have to go into the codebase, find where the changes need to be made, refer to documentation to ensure they are using the correct pattern, and so on.

APM and USM may look similar, but they solve different problems. Here’s how to choose the right one — and what to do when your stack doesn’t support either.