API Traffic Replay Testing: The Definitive Guide (2026)
What is API traffic replay testing? Capture, sanitize, and replay production traffic. Compare GoReplay vs WireMock vs Speedscale vs proxymock.
Read the guideTraffic replay guides
Traffic replay: test changes against real API behavior
Capture production interactions, remove sensitive data, and replay the same behavior in development, staging, or CI. These guides cover the workflow from first recording to release gate.
Start here
Start with the complete traffic replay guide
Choose what you need to do
Learn how replay works
Understand capture, isolation, replay, and the tradeoffs behind a production-grade system.
Apply it to delivery
Use recorded traffic for debugging, migrations, refactoring, and CI regression tests.
Handle real-world data
Protect sensitive payloads and solve the authentication problems that appear during replay.
All traffic replay articles
Traffic Replay Tutorial: Capture, Replay, Read Results
Capture one service's API traffic, replay it against a Kubernetes test workload, and use the report to tell a regression from a replay setup problem.
Load Test PostgreSQL Instantly using Production Recordings
Record the queries your app sends to PostgreSQL in Kubernetes, then replay them against a QA database as a load and regression test. No scripts to write.
Test Your MySQL 8.4 Upgrade With Real App Queries
Replay your app's recorded MySQL statements against 8.4 to catch upgrade regressions, then load test the database with the same workload using proxymock.
Test PostgreSQL With the Queries Your App Actually Runs
Replay recorded PostgreSQL queries to catch schema regressions and run realistic database load tests with proxymock, using the CLI or an AI assistant.
Use AI and traffic replay to test AI-generated code
Have your coding agent test AI-generated code with proxymock: capture working API traffic, replay it against changes, and inspect the results.
Synthetic Monitoring Is Broken. Your Production Traffic Can Fix It.
Synthetic monitoring depends on scripts engineers maintain by hand. Capturing and replaying real production transactions turns customer behavior into tests.
Capture once, test forever
Production traffic is the most complete record of what your system does, and most teams throw it away. One capture powers reproduce, validate, and sandbox.
The DIY Traffic Replay Trap: Why AI Scripts Fail at Scale
AI-generated scripts seem like a quick win, but DIY traffic replay tools become a maintenance nightmare at scale. Here's why Speedscale beats the prompt.
Replace API Synthetics with Traffic Replay
UI synthetics only tell you something is broken. Traffic replay per microservice isolates failures before any human walks up. Zero scripts required.
Replay real traffic before release
Turn production API behavior into repeatable tests without writing every scenario by hand.