Page SEO checker (HTML)
Open the page in your browser, use View source (Ctrl+U), copy everything and paste it here. The analysis runs in your browser and lists the problems by importance.
How to useCheck your page's SEO
Available in: 
Page SEO checker (HTML): what it is for
Paste the page source and the analysis lists serious problems and warnings: missing or badly sized title and meta description, missing or repeated H1, headings out of order, images without alt or without width and height, noindex, canonical, viewport, language, charset, incomplete Open Graph, missing or invalid JSON-LD, links without text and thin content.
The result includes a score from 0 to 100 and counts of words and internal and external links. Nothing is sent to a server.
How to use
- Open the page source (Ctrl+U) and copy everything.
- Paste the HTML in the field.
- Fix the serious problems first, then the warnings.
When to use it
- Review a page before publishing.
- Find what is missing in a client site's SEO.
- Check sites made with builders and templates.
Frequently asked questions
Why paste the HTML instead of the URL?
For security, browsers do not let one site read another site directly. By pasting the source code, the analysis runs on your device, works even on pages that are not published yet and nothing is sent to a server.
What is checked?
Title and length, meta description, number of H1s and heading order (H1 to H6), images without alt text, canonical, meta robots with noindex, html language, mobile viewport, Open Graph tags, structured data (JSON-LD), internal and external links and amount of text.
Sites built with React or Vue show up empty. Why?
On those sites the content is built by JavaScript after the page opens, so the source code has almost no text. To analyze them, use the browser's Inspect, right-click the html tag and copy the outerHTML.
Is it really free?
Yes, 100% free. No sign-up, no subscription and no usage limits. All Tools123 tools are free and run right in your browser.