In 2014, Pact created an entire engineering discipline. Consumer-driven contract testing — the idea that the API consumer, not the provider, should define what compatibility means — was a genuine breakthrough. It solved problems that integration testing couldn't, with mathematical certainty, in CI. The Pact Foundation's specification has been ported to twelve languages. PactFlow, the commercial parent, was acquired by SmartBear in 2023. Contract testing as a category exists because Pact exists.
And yet, by every survey I can find, fewer than 5% of microservices teams actually do it.
That's not a Pact failure. It's a category failure, and Pact is the closest thing to a positive proof of why.
The Pact thesis
Pact's premise is simple and correct:
