Paste a domain. Byline reads the site the way a visitor would, works out which searches it has the authority to win, and scores what is missing. No account, no card, nothing to install.
Up to a dozen pages, fetched the way a reader gets them. Publish dates come from your own sitemap, so the report is measuring your site rather than guessing at it.
Topics drawn from what the site already covers, not from a generic list for your industry. If you have no page on something you could clearly own, that is the gap.
The same domain scores the same twice. Where a signal is missing the report says so rather than inventing a number to fill the slot.
Topics you could own with no page answering them.
How long since anything was actually published.
Whether the articles are long enough to answer anything.
Whether publishing is a habit or a burst two years ago.