What are the two main types of web services?

• A. FTP and SMTP
• B. GraphQL and gRPC
• C. SOAP and RESTful
• D. SOAP and GraphQL

Answer: (C)

Web services come in two broad styles for exposing functionality over the web: SOAP-based services and RESTful services.

SOAP is a protocol that defines a strict XML envelope for messages, with built-in standards for security, transactions, and error handling. It aims for high interoperability across different platforms and languages, which is why it’s still used in many enterprise integrations.

RESTful services follow an architectural style that leverages standard HTTP methods (like GET, POST, PUT, DELETE) and resource-based URIs. They are stateless, lightweight, and commonly exchange data in JSON, making them easy to build and consume with web technologies.

These two represent the main, widely adopted approaches for web services, covering both the traditional, protocol-driven model (SOAP) and the scalable, HTTP-based model (RESTful).

Other options mix in different technologies that aren’t considered the primary two categories of web services. For example, FTP and SMTP are for file transfer and mail, not web services; GraphQL and gRPC are powerful API approaches but are not categorized alongside SOAP and RESTful as the two main web service types.