Explain the difference between server-side rendering, static generation and client-side rendering.

All three produce the same page; they differ in when the HTML is built.

• Client-side rendering (CSR) — the server sends a near-empty HTML shell and JavaScript builds the page in the browser. Cheap to host and excellent for highly interactive applications behind a login, but the first paint waits for the bundle to download and run, and crawlers see little without executing JavaScript.
• Server-side rendering (SSR) — HTML is built on the server for each request, then hydrated in the browser. Fast first contentful paint and good for SEO, at the cost of server work on every request and a gap where the page looks ready but is not yet interactive.
• Static site generation (SSG) — HTML is built once at deploy time and served from a CDN. The fastest and cheapest option by a wide margin, but the content is fixed until the next build. Incremental regeneration softens this by rebuilding individual pages on a schedule or on demand.

How to choose: content that is the same for everyone and changes rarely — marketing pages, documentation, blogs — should be static. Content that is personalised or changes constantly needs SSR. A dashboard behind a login can be CSR, because SEO is irrelevant and the shell can be cached.