Which protocol is mostly supported by REST services?

• A. SMTP
• B. HTTP
• C. FTP
• D. SSH

Answer: (B)

REST services primarily rely on HTTP because it provides a stateless communication protocol that is well-suited for the architecture of RESTful web services. HTTP supports various methods such as GET, POST, PUT, DELETE, and others, which align well with the CRUD (Create, Read, Update, Delete) operations that RESTful APIs are designed to perform.

The use of standard HTTP status codes also allows for clear communication of responses and error handling between clients and servers. Additionally, since HTTP is widely used for web resources, it integrates seamlessly into web applications, making it easier to invoke REST services over the internet.

Other protocols like SMTP, FTP, and SSH serve different purposes. SMTP is primarily used for email transmission, FTP is designed for transferring files, and SSH is used for secure remote access to systems. None of these protocols fit the specific needs of RESTful APIs in the way that HTTP does.