One-time payment. Lifetime deal.

    Test responsive designs faster with this browser built for web developers

    Extended Access to this deal is exclusively available to AppSumo Plus members for a limited time.

    If you are not an AppSumo Plus member, you can join now and purchase this deal before Extended Access ends.

    It’s almost funny that you’re trying to build a super fast website when your own browser is weighed down by 70 open tabs. (“Trust me, closing them would also slow me down.”)

    With all your work spread across multiple devices, browsers, and conditions, you’re bound to make a mistake and give some bad actor the power to break your site.

    Wish there was a browser created specifically for web development that let you access all your tools from one place?

    Introducing Sizzy.


    too long didn't read
    Test and debug your website on multiple devices at the same time
    Access a full suite of developer tools built right into your browser


    Allows Existing Accounts


    Sizzy is a web browser made specifically for responsive development that lets you handle all your web dev needs from one window.

    Save time testing

    With just one click, Sizzy lets you preview your websites on different screen sizes and devices simultaneously.

    • Sync your window navigation across devices, from clicks to scrolls to zooms
    • Align your device windows in horizontal, vertical, grid, or float mode to suit your screen setup
    • Customize the settings for every device including border color, browser, and OS

    Multi-device testing

    Test your website or app on multiple devices at once.

    Full suite of web developer tools

    Say goodbye to downloading random Chrome extensions! Sizzy comes packed with a suite of tools for front-end developers right in the box.

    • Access tools like API inspector, session manager, and CSS overrides inside your browser
    • Disable certain web features like animations, transitions, and GIFs for better performance
    • Enable split viewing to see multiple browser tabs at once

    Developer tools

    Access every tool a front-end developer could dream of right out of the box.

    Smooth context switching

    Even better, Sizzy lets you organize tabs, notes, bookmarks, API requests, and code snippets into separate projects.

    • Switch to any project to find all your tools right where you left them
    • Use Zen Mode to hide everything except the project you’re currently working on

    Project manager

    Separate your work into projects that will load exactly as you left them.

    Create professional screenshots

    Thanks to its advanced algorithm, Sizzy can take high-quality screenshots of your website without broken styling or bugs.

    • Take scrolling, full-page screenshots of any website
    • Move and resize your devices on a free canvas, choose a background, and take a screenshot or video for easy reference

    Photo Studio

    Take high-quality screenshots of your site on multiple devices with ease.

    Sizzy gives you everything you need to simplify your web development workflow, from simultaneous testing across multiple devices to project organization.

    Develop websites faster.

    Get lifetime access to Sizzy today!

    From the founders

    A message from Sizzy

    Howdy Sumo-lings! 🚀

    I’m Kitze, the creator of Sizzy.

    Ever found yourself buried under tabs and struggling with clunky dev tools? That was me, drowning in frustration, until Sizzy came to life.

    I couldn't stand it anymore. Every other creative field has specialized tools, yet web developers are left with a generic browser where dev tools are an afterthought.

    When I’m developing web apps and websites I don’t want to use the same tool that my grandma is using for shopping.

    Enough was enough!

    So, I set out to build Sizzy—a browser tailored specifically web developers and QA testers.

    With Sizzy, you'll experience the joy of seamless multi-device testing and debugging, without the hassle of switching between tools, windows, or losing precious time.

    Since our launch, the response has been overwhelming. Developers like you, hungry for a tool that truly understands our needs, have embraced Sizzy with open arms.

    No fancy investors here—just a passionate developer on a mission to make your life easier. Join me in this journey to redefine the way we develop and test websites.

    Here's to frustration-free coding!



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