Seems easy but yet a tricky interview question. Here is the answer by Katalon experts:
During the API testing process, a request is raised to the API with the known data. This way you can analyze the validation response. While testing an API, you should consider:
- Accuracy of data
- Schema validation
- HTTP status codes
- Data type, validations, order and completeness
- Authorization checks
- Implementation of response timeout
- Error codes in case API returns, and
- Non-functional testing like performance and security testing