Error masking is an essential aspect of error handling that prevents exposing sensitive data through error messages. Instead of revealing detailed information about the internal system, error masking provides a generalized and user-friendly message while logging the detailed error information securely for system administrators. This practice helps in maintaining the security of the system by not divulging critical information to potential attackers or unauthorized users.

The HTTP method PUT is idempotent and used for updating resources in RESTful APIs. Idempotent means that making the same request multiple times will have the same effect as a single request.

In Postman, "Environments" are used to automate test runs across multiple environments. Environments allow you to set up different configurations and variables for your API tests, facilitating testing in various scenarios.

Mocking vs Stubbing in API Testing

Virtualized services in API testing offer efficient resource utilization, allowing multiple tests to run concurrently on the same infrastructure, reducing resource costs and time.

Effective communication ensures that developers and testers share a common understanding, preventing issues, and promoting collaboration throughout the software development lifecycle. It minimizes misunderstandings, speeds up the development process, and reduces the need for extensive testing later on.

Continuous Integration (CI) streamlines the integration of code changes, promoting collaboration between developers and testers. It ensures that changes are regularly integrated into a shared repository, preventing isolated work and reducing integration issues.

Contract testing commonly uses Pact as a tool for validating API contracts. Pact is designed to ensure that the contracts between services are honored, enabling better communication and collaboration.

Boundary value analysis is a testing technique that explores the behavior of a system at the edges or boundaries of the input domain. In the context of negative testing in APIs, it helps identify potential issues that may arise at the upper and lower limits of input values. By testing extreme values, testers can uncover vulnerabilities that might not be apparent with typical inputs.

API testing is typically performed during each sprint in Agile development. This approach ensures that APIs are tested iteratively, allowing for early identification and resolution of issues, aligning with the Agile principle of delivering working software at the end of each iteration.