How to Capture and Replay Real HTTP Traffic with GoReplay for Accurate Testing

When testing a staging environment, using real production HTTP requests can provide more accurate results.

GoReplay captures live HTTP traffic and replays it.

Usage Example

Real-time forwarding

For instance, forward requests from port 8000 (production) to port 8001 (test):

./gor --input-raw :8000 --output-http="http://localhost:8001"

The command listens on port 8000 and forwards all traffic to the specified address until stopped.

Recording and replay

Recording ./gor --input-raw :8000 --output-file=requests.gor The --output-file option specifies the file to save captured requests.

After stopping, a requests_0.gor file is generated.

Replay

./gor --input-file requests_0.gor --output-http="http://localhost:8001"

The --input-file selects the recorded file, and --output-http defines the target address.

Request filtering

Collect only requests under /api:

./gor --input-raw :8080 --output-http staging.com --http-allow-url /api

Collect requests with header api-version matching ^1\.0\d:

./gor --input-raw :8080 --output-http staging.com --http-allow-header api-version:^1\.0\d

Adjust playback speed

Replay at twice the real speed:

./gor --input-file "requests.gor|200%" --output-http "staging.com"

Installation and Testing

Download from https://github.com/buger/gor/releases, extract the binary, and run it directly.

For quick experimentation, start the built‑in file server: ./gor file-server :8000 Visiting http://localhost:8000 lists local files, allowing you to simulate different environments.

Official website: https://goreplay.org with detailed documentation.