Web APIs facilitate communication by allowing different software applications to share data and functionality through standardized protocols. This enables applications to interact and exchange information, making them more versatile and interconnected.

SQL Injection is a common vulnerability involving unauthorized commands being sent to a database via an API. Attackers can manipulate input data to execute malicious SQL queries, potentially gaining unauthorized access to the database and compromising the security of the API.

Rate limiting in conjunction with API keys is used to restrict the number of API requests that a single user or application can make within a specified time frame. This helps control excessive usage, protect against abuse, and ensure fair and efficient use of API resources.

RESTful APIs are considered Stateless because they do not maintain any information about previous requests. This architectural style allows each request from a client to be independent, enhancing scalability and performance.

SOAP APIs are often used in enterprise settings due to their support for Flexibility and extensibility. The XML-based nature of SOAP allows for complex data structures and is well-suited for diverse enterprise requirements.

B. Analyzing server logs and performance metrics is a crucial step in debugging frequent timeouts in a RESTful API. By examining logs and performance data, you can identify patterns, potential bottlenecks, and the root cause of the timeouts, allowing you to take informed corrective actions. Checking the user interface or reinstalling the software is unlikely to resolve the issue effectively.

In this case, the most appropriate approach is option C. To ensure effective testing of microservices with interaction, you should design integration tests that validate the communication and data flow between microservices. Options A and B neglect integration testing, which is crucial for detecting issues in the interactions between services. Option D relies on manual testing, which can be error-prone and time-consuming.

In a RESTful API, the HTTP method "GET" is used to read a resource. The GET request is used to retrieve data from the server without making any changes to the resource.

Developers use Postman when working with APIs to test and interact with them. Postman is a popular API client tool that allows developers to send API requests, view responses, and test the functionality of APIs. It provides a user-friendly interface for making API calls and is widely used for debugging and exploring APIs during development.

A SOAP API uses XML (eXtensible Markup Language) to format the messages that are sent between the client and server. XML provides a structured way to define and exchange data between applications in a standardized format.