Flexor — Multi-Device Web Preview for VS Code

Preview your web app on multiple devices at the same time, right inside VS Code. No tab switching, no external tools.

Flexor is a device emulator built for web developers who want to see how their designs hold up across different screen sizes without leaving the editor. Open a grid of devices, point them at your localhost, and watch everything update in real time as you code.

What it does

• Multi-device grid — View up to 10+ devices side by side in a responsive layout
• Built-in presets — iPhone 12/15, Samsung Galaxy, iPad, MacBook, Desktop, and more
• Custom profiles — Add any screen size you need with custom width, height, and DPR
• Drag-to-resize — Tweak dimensions on the fly to test breakpoints
• Live reload — Changes appear on all devices instantly as you save

Getting started

1. Install Flexor from the VS Code Marketplace
2. Open the Command Palette (Ctrl+Shift+P or Cmd+Shift+P)
3. Run "Open FLEXOR Device Emulator"
4. Pick a preset or enter custom dimensions
5. Enter your localhost URL (e.g. http://localhost:3000)
6. Start coding — your changes show up live across all devices

Creating custom devices

If your target device isn't in the presets, you can add it in a few clicks:

1. Click the + button in the device selector
2. Enter width and height in CSS pixels
3. Set the Device Pixel Ratio (DPR)
4. Save and preview

Common dimensions for reference:

Requirements

• VS Code 1.95.0 or later
• A local dev server (optional — you can also test any live localhost URL)

Privacy

Flexor runs entirely on your machine. No remote connections, no data collection, no telemetry, no analytics. Your preferences are stored locally in VS Code.

Known issues

• WebSocket reconnection may take a few seconds if your network drops
• Very large CSS files (1MB+) can cause slight lag on updates
• External resources may be blocked by CORS depending on your setup

Roadmap

Planned for upcoming releases:

• Touch and gesture simulation
• Screenshot capture with device frames
• Network throttling (3G, 4G, 5G, WiFi)
• Responsive breakpoint analyzer
• Browser console integration

Release notes

1.0.1 (2025-12-12)

• Fixed webview initialization errors in marketplace builds
• Improved build pipeline stability

1.0.0 (2025-12-11)

• Initial release
• Multi-device grid with real-time sync
• 8 built-in device presets
• Custom device profile creation
• Dark UI theme
• WebSocket-based file watching

Contributing

Found a bug or have a suggestion? Open an issue or pull request on GitHub.

License

MIT — free to use and modify. See LICENSE for details.

Built by developers, for developers.