API testing is important for ensuring that your API performs as expected when faced with various expected and unexpected requests. This process is designed to test not only the API’s functionality — but also its reliability, performance, and security. API testing offers several advantages over other types of testing, like unit and UI testing.

Automated API Tests are faster to run and lower in cost to develop compared to UI tests. They enable the developers to perform self-tests as part of the CI/CD pipeline as these tests can give quick feedback on their changes, thus generally considered for start-ups with lesser funds and resources. According to data from Andersen Lab, a UI test runs for approximately seven minutes while an API test runs for 12 seconds. This means an API test is about 35 times faster than a UI test, which makes it quicker and easier to identify and resolve bugs.

Test Automation for APIs is needed to detect defects early and ensure quality through the application development cycle. However, Automated Testing is a strategic decision that requires a scope of work and an execution plan. If done without a plan, Automation can be chaotic.