sveltekit

Run npm create svelte@latest, choose the Skeleton project with TypeScript, then define pages as +page.svelte files under src/routes. Add +page.server.ts for server data loading and +server.ts files for API endpoints.

Form actions are defined in +page.server.ts as an exported actions object that receives formData from POST submissions. Use fail() for validation errors and redirect(303) after success, and apply use:enhance on the form for progressive enhancement.

+page.ts is a universal load function that runs on both server and client, while +page.server.ts runs only on the server. Use the server variant for database queries, secrets, and auth logic since it never ships to the browser.

Yes, SvelteKit controls rendering per route with page options. Set prerender = true for static generation at build time, ssr = true for server rendering per request, and csr = false to disable client-side hydration.

The locals object is only populated if you set it in src/hooks.server.ts before calling resolve(). Add a handle function that reads the session cookie, verifies the token, and assigns the result to event.locals.user.

Form actions are tied to page routes, so they do not fit APIs consumed by external clients or mobile apps. For those cases, create standalone +server.ts endpoints that accept and return JSON instead.