GoReplay - HTTP Traffic Replay Tool

GoReplay Website

Project preview

Project Overview: I created GoReplay in 2013 as an open-source tool to help developers test and debug their applications by capturing and replaying real HTTP traffic. The project has grown from a personal need into a widely-used solution adopted by companies worldwide for testing their web services.

I started GoReplay as a side project to solve my own testing headaches - I needed a way to test new code changes against real production traffic patterns. The existing solutions were either too complex or didn’t work at scale, so I built something simple that just worked.

What started as a personal tool quickly gained traction in the developer community. GoReplay became the go-to solution for “shadow testing” - the practice of testing new code by replaying real user traffic to it. Major tech companies like GitHub, Shopify, and other Fortune 500s adopted it as a critical part of their testing infrastructure.

The project grew organically through word of mouth in the developer community. Teams loved how easy it was to capture real HTTP traffic and replay it for testing. I kept the tool focused on doing one thing well - helping developers confidently test their changes against real-world usage patterns.

Today, GoReplay is considered the de-facto standard for traffic replay testing, with over 18,000 GitHub stars and widespread adoption across the industry. I continue maintaining it as an open source project, guided by real user needs rather than feature checklists.

Written in Go with a focus on performance, the tool handles everything from basic HTTP to WebSocket traffic. But the technical details matter less than the core problem it solves - giving developers confidence that their changes work with real user behavior.

Outcome

GoReplay has become a trusted tool in many developers’ testing workflows, with over 18,000 GitHub stars and adoption by major companies. It’s helped countless teams improve their testing processes by enabling them to test against real production traffic patterns. The project continues to evolve with regular updates and community contributions.

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