The on-page SEO checklist: what to check on every page

October 10, 2026·4 min read

This on-page SEO checklist covers what you control inside a single page's HTML. Work through it in order, starting with indexability, then title and description, headings, content, links, images, structured data and social tags. Each item takes a line or two here, with a link to the post that covers it in depth.

Order matters. A perfect title on a page carrying noindex earns nothing, so start with the checks that decide whether the page can appear at all, and polish later.

Indexability: can this page appear in search at all?

Check this first, because every other fix depends on it.

Status code. The URL returns 200, not a redirect or an error. A 200 is still no promise of indexing, as HTTP 200 but not indexed explains.
No stray noindex. Search the source for noindex in a meta robots tag, and check the response headers for X-Robots-Tag. See what noindex does.
Canonical points at itself. A page you want ranked should name its own URL in rel="canonical", not a parameter variant or the home page. The canonical tag guide covers the edge cases.
Snippet controls are intentional. A leftover nosnippet or max-snippet:0 hides your text from results. See nosnippet and max-snippet.
Size is sane. Bloated HTML with inline scripts and base64 images can push your content past what crawlers read. See page size and SEO.

Title tag and meta description

These two tags are your search listing, so write them for the person scanning results.

One title, unique to the page. Put the words people search for first. Google says there is no length limit on the <title> element, but it truncates title links to fit the device, so the end of a long title often disappears. Details in the title tag and SEO title length.
Expect Google to rewrite it. Google's title link documentation lists other sources it can use instead, including the H1, og:title and anchor text of links pointing at the page.
One meta description that says what the page delivers. Google shows it when it describes the page more accurately than the page text alone, per its snippet documentation. See meta description and meta description length.
Title and description differ. Copying one into the other wastes the second line of your listing.

Headings and content

Headings are the page's outline, and the body is what gets matched to the query.

One H1 that names the topic. It should agree with the title. Multiple H1s will not break a page, but one is clearer. See the H1 tag.
H2 and H3 in order, none empty. Do not skip from H2 to H4 for styling. Use CSS for size. Header tags has examples.
The target query appears in the title, H1, URL path and body.
The answer comes early. State the main point in the first paragraph, then support it.
Readable copy. Flesch reading ease explains the score.
The copy is in the HTML. Text injected by JavaScript after load may be missed by crawlers that do not run scripts.

Links and images

Links tell crawlers what else matters on your site. Images need text a crawler can read.

Real <a href> links. Google's link guidance says it reliably extracts <a> elements with an href. A span with an onclick handler may never be followed.
Descriptive anchor text. Name the destination page's topic.
Every important page is linked from somewhere relevant. See internal linking for a working method.
Alt text on informative images. Google calls alt text the most important image attribute in its image SEO guide. Describe the image, do not stuff keywords, and use alt="" on decorative ones.
Descriptive filenames. The same guide prefers a name like my-new-black-kitten.jpg to IMG00023.JPG, though it calls the filename a light clue.
Width, height and modern formats. The image SEO checker flags missing dimensions, heavy files and images that could be WebP.

These change how the page looks in search results and in shared links.

JSON-LD that matches the page. Mark up what is visible, such as Article for posts and Product for products. Start with the schema markup guide and validate with the schema checker.
Open Graph tags. Set og:title, og:description, og:image and og:url on every shareable page. See Open Graph tags.
A share image at the right size. A wrong ratio gets cropped badly. OG image size has the numbers, and the Facebook Sharing Debugger post covers refreshing a cached preview.
A favicon. Google shows it next to your result. Favicon size has the requirements.

Run an on-page SEO check on your page

Our On-Page SEO Checker covers the title, description and heading part of this checklist in one run. Give it a URL and it reports missing, short or long titles and descriptions, duplicate tags, a title copied into the description, and how the snippet clips in search. It lists the H1 to H6 outline and flags a missing H1, several H1s, an H1 that is not first, skipped levels and empty headings.

Add a target query and it also checks whether the query words appear in the title, H1, URL path and body, and flags images without alt text, pages under 50 words and pages set to noindex. It reads the HTML as served, so tags injected by JavaScript after load are not seen, and it does not report rankings or search volume.

Each run of the On-Page SEO Checker costs 8 credits.