API performance testing is the process of checking the robustness, responsiveness, and stability of an application programming interface (API). This type of testing helps to ensure that the API can handle a particular number of requests during a set period. Performance Testing is a broad term that covers a number of different test types. Each has its place and purpose in your overall API testing strategy. This article will review Load Testing, Stress Testing, Soak Testing, Spike Testing, and Breakpoint testing.