goreplay

GoReplay is an open-source tool written in Go that solves a common testing headache: how do you test your application with realistic traffic without disrupting real users? Instead of writing synthetic tests that may not reflect what actual users do, GoReplay quietly listens in the background on your server's network interface, records all live HTTP traffic, and replays it against a test or staging environment. No changes to your production setup are required — it runs alongside your service on the same machine.

This makes it extremely useful for verifying deployments before they go fully live, checking that infrastructure or configuration changes won't break anything, and stress-testing under real-world load patterns. Because it listens passively rather than sitting in the middle of your traffic flow, there is zero risk of it slowing down or breaking production requests.

You would reach for GoReplay when you want high confidence that a new release won't surprise you, using genuine traffic rather than guesses about what users will do. A paid GoReplay PRO extension adds support for binary protocols, cloud storage replays, and TCP session replication for teams with more advanced needs.