Networking
Server-Sent Events (SSE)
A one-way server-to-client stream over plain HTTP with built-in reconnection and Last-Event-ID resumption.
Why interviewers ask about it
The most under-used option in interviews. For notifications, progress and token streaming the client sends nothing, so a WebSocket is unnecessary statefulness.
This term is part of the free System Design interview preparation module - browse the full glossary for every definition.