I'm working on a game using the desktop app. I want to do some work to make the UI more mobile friendly, but to do this I need to be able to test what the outcome is in a mobile browser. I don't want to publish the game yet as it isn't finished. Is there anyway to preview the mobile view when developing on the desktop?

I think the usual approach is to publish the game as unlisted, so nobody else can see it. You can still replace it before publishing properly; although you might be unable to delete it.

To my knowledge, mrangel is 100% correct.

I want to do some work to make the UI more mobile friendly, but to do this I need to be able to test what the outcome is in a mobile browser.

I used to try to make my games look like I wanted them to look on mobile.

If you are a perfectionist and you value your sanity, I advise against it. There are too many little differences between mobile devices (as well as between mobile browsers).

In fact, normal desktop browsers have too many differences across the board, too.

Cross-browser compatibility is the real C-word! (Wait... Is that a word? Meh, you get the point!)

Nowadays, I just have the game print a message when loading if it's not being played in the desktop player: "This game performs best in the desktop version of Quest. You can technically play this online, but you may experience issues during play. You have been warned."