Global Simulations

Even on otherwise identical devices and browsers, a website can behave differently depending on network conditions, color schemes, locales, and more. You can model the behavior of your website under such different conditions using Simulations. You can also check how your website looks when printed, or with JavaScript disabled.

Info This article deals with running simulations on all the devices in your workspace simultaneously. To run simulations on individual devices instead, see Per-device simulations.

To run simulations, open the Simulations popup by clicking the 🧪 Test tube icon in the toolbar. Here, you can mix and match parameters to test your website under various conditions.

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Here's an explanation of what each option does.


Test how your website performs under different network conditions, such as slower (or even non-existent) connections.


Switch between a mouse pointer and a touch cursor. The touch cursor only works on devices that support it.

Color Scheme

Choose whether to use the dark or light theme. By default, Sizzy automatically chooses the theme based on your computer's current settings.

Software Keyboard

Toggle the software keyboard to test how your website looks when taking user input.


Simulate different languages to test internationalization and localization support.


Test how your website loads on browsers that have Javascript disabled.

Print Stylesheets

Check how your website will look when a visitor tries to print it