Preview a SvelteKit app on mobile inside VS Code

By Lilian Bischung · Updated 2026-10-13

Start your SvelteKit dev server with npm run dev, which serves on http://localhost:5173 by default, then run “Mobile Preview: Show” from the VS Code Command Palette. The extension detects the server, shows your app in a phone or tablet frame next to your code and reloads it each time you save.

Set up

  1. Install the extension and start your server with npm run dev.
  2. Open the Command Palette and run “Mobile Preview: Show”.
  3. Check that the address bar shows http://localhost:5173; if your terminal printed another port, type that address instead.
  4. Choose a device from the menu and edit your code.

What to check on a phone with SvelteKit

  • Transitions and animations on a small screen.
  • Layouts with sticky headers and a bottom bar.
  • Pages that depend on media queries inside component styles: check each breakpoint.

Common checks for any framework

Mobile Preview is a layout preview in a device frame, not an emulator. Check touch behavior and browser-specific rendering on a real phone before you ship.

  • The viewport meta tag is present, otherwise phones lay the page out as if it were much wider.
  • Tap targets are comfortably large and not too close together.
  • Nothing is hidden behind the notch or Dynamic Island: see the viewport sizes and cutouts on the devices page.

Frequently asked questions

What port does SvelteKit use in development?
SvelteKit serves on port 5173 by default (http://localhost:5173). If that port is busy, the dev server usually moves to another one and prints it in the terminal.
Does Mobile Preview work with SvelteKit?
Yes. It works with any page that loads in a browser, and it detects a local dev server automatically. You can also type any URL in its address bar.
Does the preview reload when I save?
Yes. It reloads each time you save a file.
Is it free?
There is a free version with three iPhone models. Pro, a one-time payment of €6.99, adds Android phones, iPads and more iPhones.

Install Mobile Preview from the Visual Studio Marketplace · Open VSX (Cursor, Windsurf, VSCodium) · Pricing

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