Mock servers for QA: WireMock and friends — when to replace a dependency with a stub
When an external dependency can't or shouldn't be run for real, you mock it. Why mock, what a good mock server does (stubs, fault injection, record/replay, verify), tools WireMock/MockServer/Mockoon/Prism/Hoverfly, mock vs Testcontainers, contract drift and Pact. A 10-point checklist.