On-page SEO checker

What the check covers

The tool fetches the page the way a crawler would, follows redirects and reads the HTML the server sends back. It pulls out what matters for the SEO of a page and sorts it into three levels: problems that can stop the page from ranking, points to improve, and what is already in order.

• Access: HTTP status code, redirect chain, HTTPS.
• Indexing: meta robots tag and X-Robots-Tag header, canonical, hreflang.
• Google result: title and meta description, with their length and estimated width.
• Structure: H1, order of the H1 to H6 headings, word count, internal and external links.
• Accessibility and sharing: images without alt attributes, mobile viewport, Open Graph tags, JSON-LD structured data.

How to read the result

Start with the problems. A noindex tag, a page returning a 404 or 500 error, a missing H1 or a missing mobile viewport come before everything else: while they are there, keyword work is wasted. Next come the points to improve, such as a title that is too long, a missing description or images without alternative text. Each line tells you the fix to make.

The thresholds used, such as 300 words for substantial content or 30 characters minimum for a title, are common-sense markers, not Google rules. A short contact page does not need 300 words. Judge each point against what the page is meant to do.

What the tool does not see

The check reads the HTML as the server sends it, without running JavaScript. If your site builds its content in the browser, part of it may be missing here. Google does run JavaScript, but later and not always completely: content absent from the initial HTML is a risk worth knowing about. The tool does not measure loading speed, the links pointing to the page, or Google rankings either. It checks one page, not the whole site.

Common mistakes

• A noindex tag left in place after a new site goes live.
• A canonical pointing to the home page or to another version of the URL.
• Several H1 headings, often the logo and the page title, or no H1 at all.
• Redirect chains: http to https, then to www, then to the version with a trailing slash.
• Images without an alt attribute, invisible to screen readers and to image search.