Local · Private · Free

On-Page SEO Checker

Paste a page's HTML for an instant, scored on-page audit: title, meta description, headings, image alts, Open Graph, structured data and more. 100% private, all on your device.

Page HTML

Your HTML is analysed in your browser, nothing is uploaded.
Can't crawl URLs across origins, paste the page source instead.

Paste a page's HTML above (or load the sample) and run the audit to see a scored on-page SEO report.

Essentials

Headings & content

Social & structured data

Links & crawlability

Top keywords

No visible body text detected.

What's working

Top priorities

, / 100

Run an audit

0Passed

0Warnings

0Failed

This audit covers the on-page signals you control in HTML. It can't measure off-page factors (backlinks, authority) or runtime behaviour (Core Web Vitals, JS-rendered content).

About On-Page SEO Checker

On-Page SEO Checker is a free, private browser tool by Digital Heroes. Paste a page's HTML for a scored audit (0 to 100) covering the title tag, meta description, heading structure, image alt text, canonical, robots meta, Open Graph, Twitter cards, JSON-LD structured data and keyword density. Because everything runs locally on your device, your HTML is never uploaded, there is no sign-up required, and the tool works offline. It is ideal for marketers, editors and developers who want to catch on-page issues before publishing.

What you can do

Score your page 0 to 100 with a weighted pass/warn/fail audit across all key on-page signals.

Check your title tag for character count and pixel width against Google's ~600 px display cap.

Audit meta description length and get an instant fix tip if it is too short or too long.

Inspect heading structure (H1 through H6) and detect skipped levels or missing sub-headings.

Find images missing alt text so you can fix accessibility and keyword relevance gaps before publishing.

Validate Open Graph, Twitter Card and JSON-LD structured data for rich social sharing and search results.

How to use On-Page SEO Checker

Open On-Page SEO Checker in your browser. No signup, no install.

Go to the page you want to audit, press Ctrl+U (or right-click, View Source), select all and copy the HTML.

Paste the HTML into the text area and click "Audit page". Or click "Load sample" to try a demo immediately.

Read your score out of 100 and review each pass, warning and failure with fix tips.

Check the Top Keywords list to verify your target keyword appears at the right density.

Frequently asked questions

Is On-Page SEO Checker free?

Yes, On-Page SEO Checker is completely free for everyone. No sign-up, no account and no usage limits.

Why do I paste HTML instead of a URL?

The tool runs entirely in your browser, which cannot fetch other websites' HTML across origins for security reasons. Open your page, use View Source (Ctrl+U) or right-click and Inspect, then copy the HTML and paste it here. Your HTML is analysed locally and never uploaded.

Is my HTML uploaded anywhere?

No. The audit runs entirely in your browser on your own device, so your HTML never leaves your computer and nothing is uploaded to a server.

Does it work offline?

Yes. This tool is a Progressive Web App, once the page has loaded it keeps working offline, and you can install it as an app from your browser.

What does On-Page SEO Checker do?

Paste a page's HTML for a scored on-page SEO audit (0 to 100) covering title tag, meta description, headings, image alts, Open Graph, structured data (JSON-LD) and keyword density.