Free browser tool
Check the SEO signals already in your HTML.
View a page’s source, paste it below, and review core metadata, heading structure, image alternatives, and JSON-LD. This tool does not fetch URLs or send your HTML to a server.
This is a focused on-page checklist, not a ranking score or a substitute for crawl, performance, accessibility, or content review.
How to use the HTML SEO checker
- Open the public page and view its complete HTML source.
- Paste the source above and run the checker.
- Review warnings in the context of the page’s purpose rather than treating them as an automatic score.
- Confirm the finished public URL can be crawled and indexed after any change.
Title and description length checks are approximate writing prompts. Search engines can display different snippets, and valid structured data does not guarantee a rich result.
What the HTML SEO check reviews
| Check | What passes | Why it matters |
|---|---|---|
| Title tag | Present, roughly 30–60 characters, specific to the page | The title is the strongest on-page relevance signal and usually becomes the search result headline. |
| Meta description | Present, roughly 70–160 characters | Often used as the snippet; a clear description improves click-through even though it is not a ranking factor. |
| Canonical URL | An absolute HTTP or HTTPS URL pointing to the preferred version of the page | Prevents duplicate URLs from splitting signals. |
| Robots directive | No accidental noindex or nofollow | A leftover staging directive can remove a page from search entirely. |
| Mobile viewport | A viewport meta tag with device width | Required for mobile-friendly rendering and mobile-first indexing. |
| H1 heading | Exactly one descriptive H1 | Confirms the page has a clear primary topic and a sensible heading outline. |
| Image alternatives | Every meaningful image has alt text | Needed for accessibility and gives search engines context for images. |
| Structured data | Valid JSON-LD that parses | Helps search engines understand the page entity and can enable search features. |
Frequently asked questions
What does an HTML SEO check look for?
This checker reviews the on-page signals inside the HTML itself: the title tag and its length, the meta description, the canonical link, the robots directive, the mobile viewport, the H1 heading, image alt attributes, and any JSON-LD structured data.
Why check HTML instead of a URL?
Checking the HTML directly works for pages that are not public yet, such as staging sites or local builds, and it lets you review exactly what the browser receives. For a live page, the free website audit tool fetches the URL for you.
How long should a title tag and meta description be?
The checker flags titles outside roughly 30 to 60 characters and descriptions outside roughly 70 to 160 characters. These are writing prompts, not rules; search engines rewrite snippets and truncate by pixel width rather than by character count.
Is my HTML uploaded anywhere?
No. The check runs in your browser and nothing you paste is sent to a server.