WireMock vs MockServer vs custom mock — what we tried and what we kept

We needed to mock 3 external APIs for our integration test suite. Tried three approaches over 6 months: **WireMock** - Pros: mature, great stub DSL, admin API for dynamic stubs - Cons: Java-first (the Python client is thin), Docker image is heavy for CI - Result: used it for 4 months, then moved on **MockServer** - Pros: better Python SDK, JSON-based configuration, can verify expectations - Cons: documentation is dense, verification API has quirks - Result: currently our primary mock for external HTTP services **Custom Flask mock** - Pros: full control, easy to simulate weird edge cases (malformed JSON, slow responses) - Cons: we own the maintenance, got complex fast - Result: kept it for 2 specific APIs that needed complex stateful behaviour If starting fresh: MockServer for most things, custom only when you need stateful or slow-response simulation.