FrontendHaltReact·Intermediate·Conceptual·1 min read
What is hydration?
Short interview answer
Hydration is React attaching behavior to server-rendered HTML by rendering a matching client tree and connecting event handling and component state. It reuses existing DOM when the initial output agrees; it is not simply downloading HTML.
Key takeaway
Explain the underlying mental model clearly, then support it with a concrete example and its trade-offs.