Server-side rendering

Server-side rendering builds the HTML for a page on the server, per request, and sends a complete document to the browser. The visitor sees content as soon as it arrives rather than after the application has started up.

It is the standard answer when a page must be fast to first paint and personalised or current — a product page with live stock, a logged-in dashboard whose first screen should not be a spinner. Search engines and link previews also receive real content without depending on running scripts.

The trade-off is that every request now costs server work, so caching strategy stops being optional, and the application must be written to run in both places. Where a page is the same for everyone, static site generation gives the same benefit without the per-request cost.