Alternatives to LT Browser
A desktop browser for building, testing and debugging responsive websites across many device viewports side by side. The listings below can replace it for an important use case. Each note says what changes if you switch.
The original
LT Browser
A desktop browser for building, testing and debugging responsive websites across many device viewports side by side.
Replacements
Listings that take over the same core job as LT Browser.
BrowserStack Responsive
A free web tool that previews how a website looks across real device screen sizes.
BrowserStack Responsive runs in the browser and previews pages on real devices rather than emulation, but only tests publicly reachable pages.
Responsive Design Checker
A free browser tool that previews a website at mobile, tablet and desktop screen sizes.
Responsive Design Checker is a free web tool with simulated viewports and no install, limited to five requests every five minutes.
Screenfly
A free online tool that shows a website at the screen sizes of phones, tablets, desktops and TVs.
Screenfly is a free web tool covering phone, tablet, desktop and TV sizes with resized views, and works only on public pages.
MobileTest.me
A web tool that previews a website inside smartphone and tablet emulator frames.
MobileTest.me previews sites in phone and tablet emulator frames on the web, but its device list is old and omits current phones.
Am I Responsive
A web tool that shows a site on desktop, laptop, tablet and phone mockups at once.
Am I Responsive shows four fixed Apple device mockups in one image for presentations, and is not meant as a debugging tool.
BrowserStack Live
A cloud service for testing websites by hand in real desktop and mobile browsers on real devices.
BrowserStack Live is a paid cloud service testing on real devices across more than 3,500 browser combinations, replacing emulated viewports with real hardware.
Also worth comparing
These listings name LT Browser as their own alternative, so the relationship runs both ways.
Blisk
Cross-device testing browser with hot reload and synced scrolling.
LT Browser shows more than 50 device presets side by side, works with sites that block iframes, and is tied to a commercial testing platform with paid tiers.
EXPERTE Bulk Mobile Friendly Test
A free online test that checks many pages of a website for mobile-friendliness at once.
LT Browser is a freemium desktop app for Windows, macOS and Linux that shows over 50 emulated device viewports side by side for visual debugging rather than bulk checks.
Polypane
Multi-viewport browser with accessibility and performance tooling built in.
LT Browser is freemium, offers more than 50 device presets side by side and works with sites that block iframes, but is tied to a commercial testing platform.
Responsively App
Developer browser that renders many device viewports side by side.
LT Browser shows more than 50 device presets side by side and handles sites that block iframes, but it is closed source and tied to a paid testing platform.
Sizzy
Developer browser with synced device previews and project workspaces.
LT Browser is freemium, offers more than 50 device presets side by side and works with sites that block iframes, but it is tied to a commercial testing platform.
TestMu AI
A cloud testing platform, formerly LambdaTest, for cross-browser, automated and AI-assisted testing of web apps.
LT Browser is a freemium desktop browser for Windows, macOS and Linux showing emulated device viewports side by side, covering responsive checks rather than an automated Selenium grid.
Similar software
Related functionality, not a direct replacement.
Can I use
A searchable web tool with browser support tables for HTML, CSS, JavaScript and other front-end features.
Selenium IDE
A browser extension that records and replays interactions to build end-to-end tests for websites.
