Mounting the Router

marko-run usually owns the whole server — you run marko-run dev and it handles everything: routing, rendering, the lot. But sometimes you already have a server — an Express app with its own routes, middleware, and API — and you don’t want to throw it away. You want to add marko-run’s pages to it.

That’s what the Node adapter is for. Instead of marko-run running the show, you write your own server entry and mount marko-run into it. This example is a complete, running app that does exactly that — read it, edit it, download it.

The custom entry

src/index.js is a plain Express app, and it’s the whole point of this lesson:

const app = express();
app.use(compression());

// An existing Express route — your own API, untouched by marko-run.
app.get("/api/status", (req, res) => {
  res.json({ status: "ok", uptime: process.uptime() });
});

// Mount every marko-run page and route into this same Express app.
app.use(routerMiddleware());

app.listen(PORT, ...);

/api/status is your own route — pure Express, nothing to do with marko-run. Then one line does the embedding:

app.use(routerMiddleware());

routerMiddleware() (from @marko/run-adapter-node/middleware) handles any request that matches a marko-run route — the file-based pages in src/routes — and passes everything else through to the rest of your Express app. That single line is the mount.

The other two pieces

Two bits of configuration make the adapter available:

• vite.config.ts registers the Node adapter: marko({ adapter: nodeAdapter() }).
• package.json points the marko-run commands at your entry — marko-run build src/index.js and marko-run preview src/index.js — rather than letting marko-run supply its own server.

And there are two ordinary marko-run pages in src/routes, / and /products, exactly like the file-based routes from Part 5. You didn’t wire them up by hand; routerMiddleware() picks them up automatically.

What you’re looking at

The preview is the Shop home page, served by Express through marko-run. Click Browse products and /products renders — another file-based route, same server. Meanwhile the hand-written /api/status route still answers as before (open it in the preview’s own tab to see the JSON). The two live side by side: Express handles what it knows, marko-run handles the pages.

This example is served as a production build (marko-run preview) so it runs anywhere, including this in-browser sandbox. That also means edits won’t hot-reload the preview here; to experiment live, download the project and run npm run dev on your machine.

Don’t want marko-run at all? Part 9’s Rendering by Hand reaches the same goal — Marko pages served by Express — using only @marko/vite, with every route written by hand.