Which statement best justifies using WebSockets?

Which statement best justifies using WebSockets?

• A. They enable no server resources and are easy to scale.
• B. They are the default for most APIs.
• C. They guarantee delivery of every message.
• D. They enable high-frequency persistent bidirectional communication.

Answer: (D)

WebSockets are built to support real-time, interactive communication by keeping a single TCP connection open and letting both sides send messages at any time. This makes them ideal for high-frequency, low-latency exchanges like chat, live dashboards, or collaborative tools, where you need continuous, bidirectional updates without re-establishing a new connection for every message. The initial handshake is followed by a persistent connection, reducing overhead and enabling true full-duplex communication. The other statements don’t fit because WebSockets do consume server resources to maintain many open connections, so they aren’t zero-resource or trivially scalable. They aren’t the default for most APIs, since REST over HTTP remains the common pattern. And while WebSockets run over TCP, which provides reliable transport, delivery guarantees at the application level aren’t automatic—the app must handle scenarios like dropped connections or message retries.

WebSockets are built to support real-time, interactive communication by keeping a single TCP connection open and letting both sides send messages at any time. This makes them ideal for high-frequency, low-latency exchanges like chat, live dashboards, or collaborative tools, where you need continuous, bidirectional updates without re-establishing a new connection for every message. The initial handshake is followed by a persistent connection, reducing overhead and enabling true full-duplex communication.

The other statements don’t fit because WebSockets do consume server resources to maintain many open connections, so they aren’t zero-resource or trivially scalable. They aren’t the default for most APIs, since REST over HTTP remains the common pattern. And while WebSockets run over TCP, which provides reliable transport, delivery guarantees at the application level aren’t automatic—the app must handle scenarios like dropped connections or message retries.