ByteByteGo | Explaining 9 Types of API Testing

Smoke Testing This is done after API development is complete. Simply validate if the APIs are working and nothing breaks.
Functional Testing This creates a test plan based on the functional requirements and compares the results with the expected results.
Integration Testing This test combines several API calls to perform end-to-end tests. The intra-service communications and data transmissions are tested.
Regression Testing This test ensures that bug fixes or new features shouldn’t break the existing behaviors of APIs.
Load Testing This tests applications’ performance by simulating different loads. Then we can calculate the capacity of the application.
Stress Testing We deliberately create high loads to the APIs and test if the APIs are able to function normally.
Security Testing This tests the APIs against all possible external threats.
UI Testing This tests the UI interactions with the APIs to make sure the data can be displayed properly.
Fuzz Testing This injects invalid or unexpected input data into the API and tries to crash the API. In this way, it identifies the API vulnerabilities.

Explaining 9 Types of API Testing