About SEO On Top
SEO On Top is a free on-page SEO audit tool. You paste a URL, the server fetches that page and scores its HTML against 33 rules covering content, technical setup, social sharing, readiness for AI answer engines and response security headers.
How an audit runs
The server requests your URL with an ordinary HTTP GET and parses the HTML it receives along with the response headers. It follows up to five redirects, checking at every hop that the target is a public web address on a normal web port. It also fetches robots.txt and llms.txt and, when robots.txt declares no sitemap, checks for /sitemap.xml — and if robots.txt closes the whole site to automated tools, the audit stops instead of reporting. Each rule returns pass, warning or failure together with the evidence it found, so you can see exactly what the tool read.
How the score works
Every rule carries a weight reflecting how much it affects SEO. A pass earns the full weight, a warning earns half, a failure earns nothing. The total is normalised to 100 and mapped to a letter: A from 90, B from 80, C from 70, D from 50, and F below that. The score is a summary of the rules on this page — not a prediction of where you will rank.
What it deliberately does not do
It does not execute JavaScript, so a page that renders its content entirely on the client will score lower than a user would experience. It audits one URL per run rather than crawling a site. It does not measure Core Web Vitals, backlinks or keyword rankings, and it never signs in to anything.
How it is built
Next.js on the App Router, Tailwind CSS for styling, Cheerio for HTML parsing and Supabase for optional audit storage. The audit runs server-side, so nothing depends on the visitor's browser or network.