Web Architecture: Pick the Rendering Strategy Up Front

Two defaults Claude reaches for that are usually wrong: rendering everything in the browser, and hand-building a multi-page app from vanilla HTML/JS. Both should be a deliberate up-front choice, and for most real sites the better answer is server-rendered HTML and a framework. Raise these even when the user didn't ask, the same way you'd raise a WAF before production.

Default to server-rendered HTML, not client-rendered

For anything where content, SEO, or first paint matters, the content must be in the initial HTML response, not painted afterward by client JavaScript. Client-side rendering (a blank shell that fetches and renders in the browser) means a blank screen until the bundle loads and runs, a slow LCP, and content that many crawlers and LLM retrievers never see because they don't reliably execute JavaScript. Server-render it instead:

• SSG (static generation): render at build time, serve static from a CDN. Fastest, cheapest, most cacheable. The default for content that doesn't change per request, marketing, docs, blog, listing and category pages that can be rebuilt.
• SSR (server-side rendering): render per request on the server. For dynamic, personalized, or auth-gated content that can't be baked at build time.
• CSR / islands: render in the browser only for the genuinely interactive parts, or for app-like surfaces behind a login where SEO is irrelevant (a dashboard). With an islands approach (Astro) the page ships as static HTML and only the interactive components hydrate.

Pick per page, you can mix: a static marketing page (SSG), a personalized account page (SSR), and an interactive widget (an island) in the same site.

Several pages means reach for a framework

If the project has multiple pages, a shared layout, routing, or real data fetching, hand-rolling it in vanilla JS is a maintenance and performance trap, and it's Claude's default unless told otherwise. Reach for a framework (Next.js, Astro, SvelteKit, Nuxt, Remix). They give routing, SSR and SSG, code-splitting, data loading, and image optimization out of the box, and crucially they give you SPA-style client navigation on top of server-rendered initial HTML, so you get the smooth multi-page app feel without shipping a blank client-only SPA that breaks first paint and SEO.

Note the distinction: a pure client-rendered SPA is the thing to avoid for content sites. A framework that does SSR/SSG with client-side navigation gives you the app experience and keeps the content in the HTML.

But match the tool to the project

Don't overcorrect. A single static page, a landing page, or a tiny embeddable widget does not need Next.js, plain HTML and CSS is the right, lighter call, and reaching for a heavy framework there is its own mistake. The failure runs both ways; the common one is under-reaching (vanilla everything, rendered in the browser), but over-engineering a trivial page is real too. The decision is: how many pages, does content need to be crawlable and fast, and how interactive is it, then pick the lightest thing that satisfies those.

This skill is built to grow. Add a rule when a real architecture call has a stable, defensible answer.