Been using Responsively App for a while but the context
switching was getting to me — separate window, separate
process, alt-tab constantly.
Built responsive-dx to solve it. It's an npm dev dependency
that injects a synchronized multi-viewport panel directly
into your localhost.
One command to set it up:
npx responsive-dx init
It detects your framework automatically (Next.js, Vite,
Remix, Astro, Gatsby) and adds the component to your layout
file. Nothing to configure manually.
What it does:
- Mobile, tablet, and desktop frames side-by-side
- Scroll one → they all scroll (real DOM sync, not emulation)
- Click syncs, input syncs, dark/light theme syncs
- Focus mode: one click to zoom any single frame
- iPhone notch on mobile, macOS chrome on desktop
The frames load any localhost URL — so even though the
wrapper is React, it works for Vue, Svelte, Angular, Rails,
Django, whatever you're running locally.
Zero dependencies. Tree-shaken out of production builds
completely.
GitHub: https://github.com/respodx/respo
npm: https://www.npmjs.com/package/responsive-dx
Happy to answer any technical questions.