Embr × SvelteKit sample

A minimal SvelteKit SSR sample for Embr, using @sveltejs/adapter-node so the app runs as a long-lived Node server (not a static export, not serverless).

Exercises:

• Request-time SSR via +page.server.ts load with prerender = false
• Client-side hydration via a Svelte 5 runes $state counter
• A dedicated /api/health route (+server.ts) for Embr's health check

Companion samples:

• Next.js App Router
• Next.js Pages Router

Deploy to Embr

npm install -g @coreai-microsoft/embr-cli
embr login
embr quickstart deploy <your-user>/embr-sample-sveltekit

embr.yaml

platform: nodejs
autoDeploy: true
run:
  port: 3000
  startCommand: "npm start"          # package.json → "node build/index.js"
healthCheck:
  enabled: true
  path: "/api/health"                 # must be a backend route, not a page
  expectedStatusCode: 200

Why these choices

• platform: nodejs — Oryx auto-detects from package.json and picks a Node LTS. Do not set buildCommand: an explicit buildCommand bypasses Oryx's Node pipeline and breaks npm install / npm run build wiring on Embr today (see embr#670).
• run.startCommand: "npm start" — resolves to node build/index.js, the server emitted by adapter-node. The adapter reads PORT from env, which Embr injects.
• run.port: 3000 — matches adapter-node's default and the Embr-exposed port.
• healthCheck.path: "/api/health" — a frontend +page.svelte would always return 200 and hide crashes. Use a +server.ts route handler.

What to check after deploy

1. curl https://<deployment>/ twice — the timestamp + nonce on the homepage should change each request (proves SSR is hitting the server on every hit).
2. curl https://<deployment>/api/health — {"status":"ok",…} with HTTP 200.
3. Open the site in a browser — the "clicked N times" button should increment (proves hydration is intact through Embr's reverse proxy).

Local dev

npm install
npm run dev

Build + run like production

npm install
npm run build        # → ./build (adapter-node output)
npm start            # → node build/index.js, listens on $PORT (default 3000)

SvelteKit-on-Embr gotchas

• Use adapter-node, not adapter-auto. adapter-auto probes for Vercel/Netlify/Cloudflare at install time and falls back to a warning build on Embr — you'll ship a container that can't npm start.
• Don't set buildCommand in embr.yaml. Let Oryx run npm ci && npm run build itself from package.json. Setting buildCommand explicitly today bypasses the Node pipeline.
• Don't prerender the SSR route. SvelteKit will happily prerender a page whose load has no dynamic input; if you want to prove SSR, set export const prerender = false on +page.server.ts (this sample does).