Preview

vantris preview serves the finished production build from outDir exactly as produced — no compilation. It's the closest local mirror of production, useful to sanity-check a build before deploying.

vantris build && vantris preview   # → http://localhost:4173

What it does

• Serves static files with correct content types.
• Applies the SPA fallback to index.html for client-side routes.
• Prints both Local and Network URLs on start.
• Optionally opens the browser with open: true.

Because it does no transformation, it can only serve what vantris build already wrote — it's a static file server pointed at outDir, with the same SPA fallback the dev server uses.

Configuration

import { defineConfig } from "vantris";

export default defineConfig({
  preview: {
    port: 4173,       // default
    host: "localhost", // default
    open: false,       // open the browser on start; default false
  },
});

See Preview Options for the full reference.

Opening the browser automatically

export default defineConfig({
  preview: { open: true },
});

Launches the default browser on macOS, Windows, and Linux when the server is ready.

Fails fast

vantris preview gives you a clear error instead of a confusing one when:

• outDir doesn't exist → "run build first".
• The port is in use → an address-in-use error.

Preview vs. Dev

	vantris dev	vantris preview
Compiles source	✅ on the fly	❌ never
HMR	✅	❌
Serves	rootDir + public/	outDir
Default port	3000	4173
Mirrors production	no	yes

Use dev while building features; use preview to verify the actual artifact you're about to ship — including hashed filenames, minification, and the base-prefixed URLs that only exist after a build.

Preview vs. a real server

preview is a convenience, not a production server. Deploy the contents of outDir to your host of choice (static hosting, a CDN, an nginx root). If you build with a base sub-path, make sure your host serves the app under that same path.