API testing is an essential part of modern software development. While sending requests and receiving responses is straightforward, the real value of API automation comes from response verification. A test is meaningful only when it validates that the API returns the correct data, structure, status codes, and business rules.In Java-based API automation, REST Assured combined with Hamcrest Matchers provides a clean and expressive way to verify API responses. These matchers help testers write readable assertions that validate numbers, strings, arrays, JSON objects, and collections with minimal code.