This tool is no longer available, because API support is deprecated
Because most people are searching on Google with a mobile device. For this reason Google introduced their mobile-first indexing strategy. On September 2020 Google will switch from primarily desktop indexing to mobile-first indexing for all websites. This means Google uses the mobile version of a website to build their indexing and for ranking. Almost all crawling will be done with Google smartphone user agent (here you can have an overview of all Google user agents ). To summarize, having your website optimized for mobile is essential to perform well in the Google search results.
The results from the Google SEO audit will help you to understand the on-page basics. To fully analyse how well a website is optimized for search, I recommend you to also have a look at these tools:
The automated mobile friendly analysis is performed based on 9 possible technical mobile accessibility factors.
Based on Google’s SEO starters guide, here are some examples and guidelines to help you create a Google-friendly website.
Further reading: https://developers.google.com/search/mobile-sites/mobile-seo/common-mistakes