Bing’s tool looks at the following criteria when determining mobile-friendliness:
- Viewport and Zoom control configuration
- Width of page content
- Readability of text on the page
- Spacing of links and other elements on the page
- Use of incompatible plug-ins
In the event that Bing is not able to assess any of the above criteria due to blocked resources, the testing tool will notify you so you can correct the problem.
Similar to Google’s mobile-friendly testing tool, when testing a page with Bing’s tool it will return an overall verdict as to whether or not the site is mobile-friendly. This is based on how much of the above criteria is satisfied. Alternatively, if a page fails the testing tool will return the reasons why.
When testing sites on both Google’s and Bing’s tools, I found that both tools picked up on the same things. One offered little advantage over the other when it comes to assessing mobile-friendliness. However, Bing’s tool was noticeably faster and arguably more user-friendly in its presentation.
If you want to determine whether or not a page is mobile-friendly, you can’t go wrong with either tool. If you value speed and presentation, you may be more inclined towards what Bing has to offer with its new tool.