Stop Guessing, Start Trusting: The Power of Contract Testing by Ashish Ghosh

A quality engineering lead at ING Bank shares why integration issues dominate production incidents and how contract testing addresses the root cause: unverified assumptions between service interfaces. Using the Mars Climate Orbiter failure as an analogy, the talk explains consumer-driven contract testing with Pact, covering the full workflow from consumer writing pact tests, generating JSON contract artifacts, publishing to a Pact broker, provider verification, and the 'can I deploy?' CI/CD gate. Best practices for handling breaking changes additively are demonstrated with a real banking payments example. Bidirectional contract testing using OpenAPI specs as the single source of truth is also introduced as an alternative for large organizations.