responsively-org/responsively-app

Responsively App

A modified browser built using Electron that helps in responsive web development.

Features

1. Mirrored User-interactions across all devices.
2. Customizable preview layout to suit all your needs.
3. One handy elements inspector for all devices in preview.
4. 30+ built-in device profiles with the option to add custom devices.
5. One-click screenshots on all your devices.
6. Hot reloading is supported for developers.

Please visit the website to learn more about the application - https://responsively.app

Download

The application is available for Mac, Windows and Linux platforms. Please download it from responsively.app

Alternatively, MacOS users can use brew

brew install --cask responsively

Also, Windows users can use chocolatey

choco install responsively

or winget:

winget install ResponsivelyApp

Linux users using an RPM Package Manager can use rpm

sudo rpm -i https://github.com/responsively-org/responsively-app/releases/download/v[VERSION]/Responsively-App-[VERSION].x86_64.rpm

otherwise, download an AppImage from the releases page

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Browser Extension

Install the handy browser extension to easily send links from your browser to the app and preview instantly.

• Download for Chrome
• Download for Firefox
• Download for Edge

MCP Server (AI coding agents)

Responsively App ships a built-in Model Context Protocol server, so AI coding agents like Claude Code and Cursor can drive the app while you build — load your dev server, switch device previews, interact with pages, and visually verify responsive layouts with per-device screenshots.

Install the app, launch it once, then connect from Claude Code:

claude mcp add responsively -- npx -y @responsively/mcp

Or add to Cursor's .cursor/mcp.json:

{
  "mcpServers": {
    "responsively": {"command": "npx", "args": ["-y", "@responsively/mcp"]}
  }
}

The app is launched on demand — connecting an agent session doesn't open it; the first tool call starts it automatically (and it stays open afterwards). If it's already running, it's reused.

Available tools:

| Tool | Description | | --- | --- | | get_app_state | Current URL, page title, layout, zoom and active devices | | navigate | Load a URL in all device previews (waits for the page to load) | | list_devices | Full device catalog, including custom devices | | set_active_devices | Change which devices are previewed, by id or name | | screenshot | Capture one or all device previews as JPEG images | | read_page | Read a preview's page text and interactive elements with CSS selectors | | click | Click an element (trusted mouse event; mirrors across previews) | | type_text | Type into a form field with real keystrokes, optionally press Enter |

Screenshots capture the visible viewport and are downscaled to at most 1000px wide.

The app's MCP server listens on http://127.0.0.1:12720/mcp (localhost only) whenever the app is running. If your MCP client can't run npx, connect to it directly — but you'll need to have the app running yourself:

claude mcp add --transport http responsively http://127.0.0.1:12720/mcp

Environment variables understood by @responsively/mcp:

| Variable | Purpose | | --- | --- | | RESPONSIVELY_APP_PATH | Path to a custom app install (auto-detected otherwise) | | RESPONSIVELY_MCP_PORT | Port of the app's MCP server (default 12720) | | RESPONSIVELY_MCP_BRIDGE | Direct path to a bridge cli.js (development override) |

Linux note: the app ships as an AppImage, so launch it once before first agent use — that's how the CLI learns where it lives.

Issues

If you face any problems while using the application, please open an issue here - https://github.com/responsively-org/responsively-app/issues

Roadmap

Here is the roadmap of the desktop app - https://github.com/responsively-org/responsively-app/projects/

Gold sponsors 🥇

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Contribute

To get started with contributing your awesome ideas to Responsively, follow the comprehensive guide here!

Get in touch

Come say hi to us on Discord! :wave:

Contributors ✨

Thanks go to these wonderful people (emoji key):

This project follows the all-contributors specification. Contributions of any kind are welcome!