What this looks at
Your home page first: whether it answers quickly, how much it weighs, whether it has a title and description a search result can show, one main heading, a layout that works on a phone, descriptions on its images and a canonical address. Then whether plain http and the www form of the address land on the same site. Then robots.txt and the sitemap, which are what a search engine reads before it reads anything else. Last, the email records your domain publishes, the same ones that decide whether your invoices reach an inbox.
What this does not do
Nothing is scanned, submitted or changed. This makes four ordinary page requests, the same as a visitor opening your home page, and reads records your domain already publishes. It never quotes your page's words back, only what was there and what was not.
What it cannot see
It looks at one page from the outside. It cannot tell you how the rest of the site is built, what the hosting is costing you, whether the WordPress behind it is up to date, or why the enquiry form stopped sending. That is the written review, and a person does it.
The written review
If the list above raises questions, send us the address and we reply by email with what we found, what we would fix first and what each thing would cost. No obligation, and if the site is in good shape we say so.