Learn how to prototype web and mobile apps

View and test your interactive prototypes in any browser

With Justinmind, you can see how your website or mobile app is going to look on different devices directly from your browser. If you click on the “Simulate” button in the top right-hand corner, a new tab will open, showing you the prototype you’ve just created in the corresponding device’s screen.

There are various options when it comes to view and test your interactive prototypes. Once you’ve selected the “gear” icon next to the Simulate button, you’ll gain access to the  ‘Simulation settings’. These settings will also be used when you publish your prototype online and invite reviewers, who will see your prototype the way you want them to see it.


The “Device” drop-down menu lists the device skins that can be used in the browser.

If ‘Web’ is selected, then a common navigator is used either when you Simulate or Publish your prototype. If you choose a mobile device, the corresponding skin will show up in the tab. The mobile simulators go beyond simple skins that wrap your screens. Scroll bars, Input text fields, Select lists and Date fields will be displayed as they would be on the real device.


If you are prototyping an application for any mobile device or tablet that is not listed, you can use the ‘Custom’ option. The custom device option can be customized to the resolution of your real device.


The Simulation Settings dialog also includes an option called ‘Scale’. This option allows you to display all content in your prototype in different sizes. It’s particularly handy if you design in Retina resolution: if your prototype is designed using that resolution, just select ‘Scale: 50%’ and it will display correctly both in the browser and real devices.

In the Simulation Settings you can also select options to reproduce gestures in mobile devices. You can manipulate the tester to rotate the device or simulate gestures like ‘pinch’ or ‘rotate’. Another useful option is the zoom, especially handy when you want to simulate a prototype for a tablet in small monitors.

Next tutorial > Test your prototypes on multiple devices >