What is an API, and how does it work? What types of APIs are available? What is RESTful API, and how does it differ from other types of APIs? What are the common methods used in RESTful API? What is an API endpoint, and how do you define it? How do you test API endpoints, and what tools do you use? How do you validate API responses, and what techniques do you use? What are the common API security vulnerabilities, and how do you prevent them? How do you handle API errors and exceptions? How do you monitor and measure API performance?
