--- title: "Traffic replay: test changes against real API behavior | Speedscale" description: "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." canonical: "https://speedscale.com/blog/category/traffic-replay/" --- Traffic 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 [![API Traffic Replay Testing: The Definitive Guide (2026)](https://speedscale.com/_astro/featured-image.BjN2zDjz_Z1s0bjT.webp)](https://speedscale.com/blog/definitive-guide-to-traffic-replay/) ### [API Traffic Replay Testing: The Definitive Guide (2026)](https://speedscale.com/blog/definitive-guide-to-traffic-replay/) What is API traffic replay testing? Capture, sanitize, and replay production traffic. Compare GoReplay vs WireMock vs Speedscale vs proxymock. [Read the guide](https://speedscale.com/blog/definitive-guide-to-traffic-replay/) ## Choose what you need to do ### Learn how replay works Understand capture, isolation, replay, and the tradeoffs behind a production-grade system. * [Part 3: Building a Production-Grade Traffic Capture and Replay System](https://speedscale.com/blog/how-to-build-a-traffic-replay-system/) * [Traffic Replay: Production Without Production Risk](https://speedscale.com/blog/traffic-replay-production-without-production-risk/) * [Eliminating Flaky Tests with Traffic Replay](https://speedscale.com/blog/eliminating-flaky-tests-with-traffic-replay/) ### Apply it to delivery Use recorded traffic for debugging, migrations, refactoring, and CI regression tests. * [From Datadog to CI Tests: Catch Regressions Before Deploy](https://speedscale.com/blog/from-datadog-to-test-suite/) * [Validate Spring Boot Upgrades with Traffic Replay](https://speedscale.com/blog/spring-boot-migration-traffic-replay-validation/) * [Refactor Safely with AI: Using MCP and Traffic Replay to Validate Code Changes](https://speedscale.com/blog/ralph-wiggum-loop-traffic-replay-mcp/) ### Handle real-world data Protect sensitive payloads and solve the authentication problems that appear during replay. * [Production Data Access for Developers: RBAC and DLP](https://speedscale.com/blog/production-data-in-developer-hands-rbac-and-dlp/) * [DLP, Traffic Replay, and the Missing Link to Software Quality](https://speedscale.com/blog/dlp-traffic-replay-and-the-missing-link-to-software-quality/) * [Fixing 403 auth errors when you replay traffic](https://speedscale.com/blog/fix-403-auth-errors-traffic-replay-proxymock/) ## All traffic replay articles Updated Oct 9, 2026 ### [Traffic Replay Tutorial: Capture, Replay, Read Results](https://speedscale.com/blog/traffic-replay-tutorial/) 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. Oct 5, 2026 ### [Load Test PostgreSQL Instantly using Production Recordings](https://speedscale.com/blog/load-test-postgresql-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. Sep 25, 2026 ### [Test Your MySQL 8.4 Upgrade With Real App Queries](https://speedscale.com/blog/mysql-load-regression-testing-real-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. Sep 24, 2026 ### [Test PostgreSQL With the Queries Your App Actually Runs](https://speedscale.com/blog/postgres-load-regression-testing-real-queries/) Replay recorded PostgreSQL queries to catch schema regressions and run realistic database load tests with proxymock, using the CLI or an AI assistant. Sep 15, 2026 ### [Use AI and traffic replay to test AI-generated code](https://speedscale.com/blog/test-ai-code-with-traffic-replay/) Have your coding agent test AI-generated code with proxymock: capture working API traffic, replay it against changes, and inspect the results. Aug 13, 2026 ### [Synthetic Monitoring Is Broken. Your Production Traffic Can Fix It.](https://speedscale.com/blog/synthetic-monitoring-is-broken-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. Jun 12, 2026 ### [Capture once, test forever](https://speedscale.com/blog/traffic-data-lake/) 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. May 15, 2026 ### [The DIY Traffic Replay Trap: Why AI Scripts Fail at Scale](https://speedscale.com/blog/ai-intern-trap-diy-traffic-replay-scalability-nightmare/) 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. Apr 19, 2026 ### [Replace API Synthetics with Traffic Replay](https://speedscale.com/blog/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. [Start Free Trial](https://app.speedscale.com/signup) [See Traffic Replay](https://speedscale.com/features/kubernetes-traffic-replay/)