What is API Testing and which tools are commonly used?
Updated Apr 28, 2026
Short answer
Testing the application programming interfaces directly to determine if they meet expectations for functionality, reliability, and security.
Deep explanation
Intermediate testing involves strategy and automation. TDD changes the workflow to 'Test First', which improves code quality and design. Integration testing moves away from units to verify the 'contract' between services. At this level, understanding mocks and stubs is vital for isolating dependencies.
Real-world example
Automating a checkout flow using Selenium or Playwright where the database is mocked to speed up execution.
Common mistakes
- Writing 'Brittle' UI tests that break every time a CSS class changes.
Follow-up questions
- What is 'shifting left' in testing?