WatchSim allows you interactively evaluate your Apple Watch UX at actual size on your iPhone or iPad.

Getting Started

To get started with WatchSim you need the WatchSim app from the app store and the free WatchSim Server running on your Mac.

WatchSim Server runs as a menu bar app. Just look for this icon:

The WatchSim app uses Apple’s Bonjour technology to automatically detect the server. As soon as the server is running it should appear on the list of available servers. The server will only accept incoming connections when the iOS simulator is running with a watch app window visible. Your Mac and iPhone or iPad must be connected to the same network. To connect to a server just tap the server name. To ensure touches are delivered correctly the simulator should be the active (frontmost) application.

Once a connection is established the following controls are available:


The auto-alignment function attempts to align the screen on bezel images that are not centered (this is the case for some downloadable bezels). The algorithm is rather naïve and may not succeed in all cases. Centering the image in your favorite image editing software is a more robust solution!

The controls can be hidden by tapping anywhere on the background. Another tap will bring them back.

Uploading Bezels

Only a simple outline bezel is included with WatchSim, but you can upload your custom bezels using iTunes file sharing. I really like Max Rudberg’s Apple Watch Bezels for ‘Bezel’ (they are the ones in the above screen shots).

Bezels should be rendered in PNG format at 326 dpi with the center of the screen in the center of the file. Two versions of each bezel should be uploaded, one for the 38mm case and one for the 42mm case. The file names should include the size and corresponding bezel file names should only differ by the size designation (for example ‘38mmGoldBezel.png’ and ‘42mmGoldBezel.png’).

Download WatchSim Server

WatchSim - Now in the App Store


Close the connection

Open the bezel chooser

Attempt to auto-align the bezel

Get WatchSim on the App Store