Responsively App is a modified web browser built with Electron that streamlines responsive web development by allowing developers to preview and test websites across multiple device viewports simultaneously. Written primarily in TypeScript and leveraging React and Redux, the application serves as a desktop tool available on Mac, Windows, and Linux platforms, with additional browser extensions for Chrome, Firefox, and Edge that enable quick link sharing from standard browsers.
The core functionality centers on mirrored user interactions across all previewed devices, meaning actions performed in one viewport automatically replicate across others, significantly reducing the time needed to test responsive behavior. The application includes 30 or more built-in device profiles that developers can customize or extend with their own device specifications. A unified elements inspector works across all previewed devices simultaneously, eliminating the need to switch between separate browser windows or developer tools. The preview layout itself is customizable, allowing developers to arrange device viewports according to their workflow preferences. One-click screenshot functionality captures the current state across all devices in preview, and hot reloading support enables developers to see changes in real-time without manual page refreshes.
The project is explicitly classified across numerous responsive design and web development categories including mobile preview, multi-device preview, cross-browser testing, viewport emulation, and layout debugging. The application is available for free download from responsively.app and can be installed via package managers including Homebrew for macOS and Chocolatey or winget for Windows. The project actively welcomes contributions and maintains a comprehensive contributing guide, with topics including contributions-welcome, good-first-issue, and hacktoberfest tags indicating accessibility for new contributors. Community engagement occurs through Discord, Twitter, and GitHub discussions, with sponsorship opportunities available through Open Collective for those wishing to support ongoing development.
