Contract Testing External APIs in PHP with Pact (Real Laravel Example)

Mocking external APIs only tests your assumptions, not the actual API behavior. Contract testing with Pact bridges this gap by defining a formal agreement between a consumer (your Laravel app) and a provider (the external API). A step-by-step Laravel example shows how to write consumer contract tests using Pact's InteractionBuilder, generate a Pact file, and verify it on the provider side via CLI or CI pipeline. The post also covers common mistakes like over-specifying responses, skipping error contracts, and not enforcing contracts in CI, plus guidance on when contract testing is worth the investment versus overkill.