Using Pact to Deploy Microservice with Confidence - Mark Bradley, Armakuni

PACT is a consumer-driven contract testing tool that helps deploy microservices with confidence by verifying API contracts between consumers and producers

Contracts are created through consumer tests, containing only the fields and interactions actually used, rather than full API specifications

PACT helps teams move fast without breaking things by validating API changes are safe before deployment using “can I deploy?” checks

The PACT Broker acts as a repository for contracts, enabling version tracking and compatibility checks between consumer-producer pairs

PACT works best for internal APIs and microservice communications rather than public APIs

Testing happens at the unit test level, replacing traditional mocking while verifying real interactions

Contracts only contain the fields and endpoints actually used by consumers, helping identify what’s safe to deprecate

PACT supports multiple languages and frameworks including Go, Java, JavaScript, PHP and others

The tool integrates into CI/CD pipelines to verify contract compatibility before deployment

Teams can gradually adopt PACT by starting with single endpoints/consumers and expanding coverage over time

PACT enables async API testing and supports multiple protocols beyond just HTTP REST APIs

The tool helps teams identify which consumers use specific API fields, making it safer to evolve APIs over time