SeoPiece
All free tools
Free tool

Free On-Page SEO Checker

Paste a URL to catch the three most common — and most costly — on-page mistakes: an accidental noindex tag, a broken canonical, and images missing alt text. No signup, nothing saved.

Fetch a URL above to run the checks.

How it works

01

Paste a URL

We fetch the page's HTML and headers directly — the same way a search engine crawler sees it.

02

Check indexability

We read the canonical tag and both places a noindex directive can hide — the meta robots tag and the X-Robots-Tag HTTP header.

03

Audit every image

Every image in the main content is listed with its alt text status, so you can spot what's missing at a glance.

Three small mistakes with outsized consequences

An accidental noindex is the most expensive on-page mistake there is — a page with it set simply doesn't appear in search results, no matter how good the content is. It usually happens from a staging-site setting that never got turned off after launch, or a CMS/SEO plugin toggle flipped by mistake. Check both places it can hide: the <meta name="robots"> tag in your HTML, and the X-Robots-Tag HTTP header — some server configs and CDNs set the header independently of what your CMS shows you, so a page can look fine in your editor and still be blocked.

A wrong canonical tag tells search engines "don't index this page, index that other one instead" — useful when you genuinely have duplicate content, actively harmful when it's pointing somewhere it shouldn't (a common bug: a canonical accidentally left pointing at a staging domain, or at the homepage on every page after a templating mistake).

Missing alt text matters for two separate reasons that often get conflated: accessibility (screen reader users rely on it to know what an image shows) and image search visibility (Google Images uses alt text as its primary signal for what an image depicts). Neither is a strong direct ranking factor for your main page, but both are real, measurable value left on the table for very little effort.

Frequently asked questions

A short, literal description of what the image shows, as if describing it to someone who can't see it — not a keyword list. "Golden retriever puppy playing in autumn leaves" is good; "dog puppy pet cute golden retriever leaves fall" is not, and can read as spam.

Purely decorative images (a background flourish with no informational content) should use alt="" — an empty but present attribute — so screen readers correctly skip them instead of reading a meaningless filename aloud. This tool flags images with alt completely absent from the tag, not the deliberate empty-string case.

No — a canonical pointing elsewhere is shown as information, not an error, since that's often intentional (paginated pages, tracked URL variants, syndicated content). It's worth a quick sanity check that it's pointing where you actually intended.

More free SEO tools

Want on-page basics handled correctly, automatically?

SeoPiece writes, researches, and publishes SEO-ready articles for you — start free, no credit card.

Start free — 5 articles