Flight Recorder in Go 1.25

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<h1>Flight Recorder in Go 1.25</h1>
  
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  Carlos Amedee and Michael Knyszek<br>
  25 September 2025
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In 2024 we introduced the world to more powerful Go execution traces. In that blog post we gave a sneak peek into some of the new functionality we could unlock with our new execution tracer, including flight recording. We’re happy to announce that flight recording is now available in Go 1.25, and it’s a powerful new tool in the Go diagnostics toolbox.

Execution traces

First, a quick recap on Go execution traces.

The Go runtime can be made to write a log recording many of the events that happen during the execution of a Go application. That log is called a runtime execution trace. Go execution traces contain a plethora of information about how goroutines interact with each other and the underlying system. This makes them very handy for debugging latency issues, since they tell you both when your goroutines are executing, and crucially, when they are not.

The runtime/trace package provides an API for collecting an execution trace over a given time window by calling runtime/trace.Start and runtime/trace.Stop. This works well if the code you’re tracing is just a test, microbenchmark, or command line tool. You can collect a trace of the complete end-to-end execution, or just the parts you care about.

However, in long-running web services, the kinds of applications Go is known for, that’s not good enough. Web servers might be up for days or even weeks, and collecting a trace of the entire execution would prod...

Get the full details here: Flight Recorder in Go 1.25 - The Go Programming Language