Pact - Consumer-Driven Contract Testing Documentation

Official documentation site for Pact, the leading open-source consumer-driven contract testing tool.

Key Takeaways

Pact is a code-first testing tool for validating HTTP and message-based integrations through contract tests.
“Contract tests assert that inter-application messages conform to a shared understanding that is documented in a contract.”
Consumer creates the contract: the consuming application writes tests against a mock provider, and Pact generates a pact file (JSON) from recorded interactions.
Provider verifies the contract: the provider replays each recorded request against its real implementation and asserts responses match.
Contracts are “enforced by executing test cases, each describing a single concrete request/response pair” — not static schema validation.
Only actively-used communication paths are tested; unused provider behaviours may evolve freely.
Pact Broker: central repository for sharing and managing contracts across distributed teams; enables can-i-deploy queries.
Supports both HTTP/REST and async messaging (Kafka, SQS, etc.).
Analogy: “testing a smoke alarm by pressing its button rather than setting your house on fire” — no full integration environment needed.

High — read directly from source.