How do you test your integration when the external system isn't ready yet?
I work in a telco company and we regularly work on integrations with external platforms — payment providers, orchestration engines, provisioning systems, partner APIs. Almost always there's parallel development and the other side isn't ready when we are.
For example, our system calls their REST endpoint and then waits for them to publish a Kafka event back to us. To simulate this during development, we use Postman to mock their REST response and then manually produce a Kafka event to our platform to simulate their async callback. Two separate manual steps — no correlation between them and every developer does this locally while QA does the same thing on a shared test environment.
Curious how others handle this. Do you use WireMock, Microcks, something else? Do you write custom stubs? How do you simulate a platform that receives your REST call and automatically fires a Kafka event back — so the whole flow is defined in one place and works the same way for devs locally and for QA on a shared environment?
Does something exist that lets you configure this kind of complex mock once — REST response plus async Kafka callback as a single flow — and share it across the whole team, so nobody is blocked waiting for the external system to be implemented, tested and deployed?