Contract testing is a simple, reliable way to make sure that each service and API plays nice with other components so you can deploy independently and safely.

In a microservices-first world, traditional testing struggles to keep up with all the potential interactions in a large, loosely-coupled system. Contract testing checks the compatibility of an API or service by validating it against an agreed contract. This straightforward method uncovers integration issues early and adds valuable transparency to compatibility expectations.

In Contract Testing in Action you'll learn:

• The core concepts and practices of contract testing
• Testing microservices with Pact
• Consumer-driven and bi-directional testing
• Building a contract testing framework
• Converting API integration tests to contract tests

Contract Testing in Action introduces the practice of contract testing through engaging hands-on examples. You'll learn how to introduce contract tests for multiple different types of communication, from REST APIs to GraphQL. By the end of this practical guide, you'll be comfortable with advanced contract testing concepts like can-i-deploy, provider states, and webhooks. You'll even get tips on how to introduce contract testing to your team and other business stakeholders.