Every check, as a list to work through

SEO

Whether search engines can index the page, and what they will show for it.

Indexing

• The page doesn't answer 200 OKindexing.status
• Too many redirects before the pageindexing.redirect-chain
• The page tells search engines not to index itindexing.noindex
• robots.txt stops search engines reading the pageindexing.robots-blocked
• No canonical linkindexing.canonical-missing
• The canonical link can't be trustedindexing.canonical-invalid
• A canonical link points at a page that can't be indexedindexing.canonical-target
• The site has no sitemapindexing.sitemap-missing
• The sitemap lists pages that can't be indexedindexing.sitemap-errors
• Language versions that don't link back to each otherindexing.hreflang-pairs
• Search Console is set up for this siteBy handmanual.search-console
• Bing Webmaster Tools is set upBy handmanual.bing-webmaster
• Staging is hidden and production is notBy handmanual.staging-blocked

Meta tags

• The page has no titlemeta.title-missing
• The title is too long or too shortmeta.title-length
• The page has no meta descriptionmeta.description-missing
• The meta description is too long or too shortmeta.description-length
• The page does not say what language it is inmeta.lang
• No viewport tag: phones show the desktop layoutmeta.viewport
• The character encoding is not declaredmeta.charset
• The site has no faviconmeta.favicon
• Pages share the same titlemeta.title-duplicate
• Pages share the same meta descriptionmeta.description-duplicate

Content

• The page has no main headingcontent.h1
• The title and the heading are about different thingscontent.title-h1
• The page has very little textcontent.thin
• Something is measuring visitsBy handmanual.analytics-installed
• Your own visits are left out of the numbersBy handmanual.analytics-excludes-team
• The Google Business Profile is claimed and rightBy handmanual.business-profile

Links

• The secure page loads insecure fileslinks.mixed-content
• Links on the site lead to missing pageslinks.broken-internal
• Links on the site point at addresses that redirectlinks.internal-redirect
• Pages in the sitemap that nothing links tolinks.orphan
• The "page not found" page helpsBy handmanual.404-page-helpful

Structured data

• Structured data that search engines cannot readstructured.json-ld-parse
• Structured data is missing something it needsstructured.required
• The site and its social accounts point at each otherBy handmanual.social-profiles-linked

Security

• The page is not served securelysecurity.https
• No HSTS headersecurity.hsts

Performance

• The HTML is sent uncompressedperformance.compression
• The HTML is heavyperformance.html-weight

Social sharing

How the page looks when its link is shared in a feed or a chat.

Social sharing

• No og:title for link previewssocial.og-title
• No og:description for link previewssocial.og-description
• og:url is missing or disagrees with the canonicalsocial.og-url
• No og:typesocial.og-type
• No og:site_namesocial.og-site-name
• No share imagesocial.og-image-missing
• The share image can't be loadedsocial.og-image-url
• The share image is too small, or the wrong shapesocial.og-image-size
• The share image is too heavysocial.og-image-weight
• The share image's format isn't supported everywheresocial.og-image-type
• The share image has no alt textsocial.og-image-alt
• No twitter:card, or one the image is too small forsocial.twitter-card
• Sharing tags are outside <head>social.tags-in-body
• The head is too big for WhatsApp to readsocial.head-within-300kb
• Sharing tags are too far down the page for Facebooksocial.tags-within-1mb

Accessibility

What a screen reader, a keyboard and a pinch of the fingers make of the page, as far as its HTML can say.

Automated checks find roughly a third of accessibility problems. Passing them is not WCAG conformance; a person with a keyboard and a screen reader finds the rest.

Accessibility

• The page has no title to announcea11y.page-title
• Screen readers can't tell what language the page is ina11y.lang
• Pinch-zoom is switched offa11y.viewport-zoom
• No main landmarka11y.landmark-main
• Headings skip a levela11y.heading-order
• Images have no alt texta11y.image-alt
• Alt text that doesn't describe the imagea11y.image-alt-quality
• Links with no texta11y.link-name
• Buttons with no namea11y.button-name
• Form fields without a labela11y.form-label
• Frames without a titlea11y.iframe-title
• Data tables without header cellsa11y.table-headers
• Sound may play on its owna11y.autoplay
• The tab order has been rearrangeda11y.tabindex
• The same id is used more than oncea11y.duplicate-id
• ARIA roles that don't exist or are incompletea11y.aria-valid
• Someone has been through the site with a keyboardBy handa11y.keyboard-walkthrough
• Someone has listened to the siteBy handa11y.screen-reader-pass

AI review

What a model makes of the words on the page: the judgements a checker cannot make.

These are a model's opinions, not rules. They are never counted as errors, they are capped by your plan, and a page is only reviewed again when its words change.

Meta tags

• The title doesn't say what the page is aboutai.title-intent
• The meta description isn't a reason to clickai.description-pitch

Accessibility

• Alt text that doesn't describe its imageai.alt-quality

Content

• The page is harder to read than it needs to beai.readability