Ten On-Page SEO Checks, Matched Against What Google Actually Says
SEO advice is full of numbers nobody can source. This page takes ten browser tools for on-page work and sets each one against Google’s own documentation, so you know which warnings reflect a Google rule and which are rules of thumb.
Featured snippets and People Also Ask: planning aids, not predictions
The Featured Snippet Preview scores a block of content for four snippet shapes (paragraph, numbered list, bulleted list, table) from its structure. That is a heuristic: Google says featured snippets are chosen automatically and there is no markup that guarantees one; you can only opt out, with nosnippet or data-nosnippet. The People Also Ask Generator builds candidate questions from templates around your keyword. They are a brainstorm for what to cover, not questions taken from Google’s results; check real result pages for the questions that actually appear.
Meta descriptions: no length limit, frequently rewritten
Google’s snippet documentation says there is no limit on how long a meta description can be; the snippet is cut to fit the device width. The 150–160 character range the Meta Description Generator aims for is a convention that tends to display in full on desktop, not a Google rule. Google also writes its own snippet from the page when it thinks that matches the query better, and an Ahrefs study found it rewrote the meta description for 62.78% of results. Write one anyway: it is the version Google uses when it does not rewrite, and what many social and chat previews show.
Canonicals: a strong hint, not a command
The Canonical Tag Generator builds a <link rel="canonical"> tag and warns about relative URLs, http on an https site, www and non-www drift and trailing-slash mismatches. Google treats rel=canonical as a strong signal among several (redirects, sitemaps, internal links) and can choose a different canonical when the signals disagree, so the tag works best when your internal links and sitemap point at the same URL.
Hreflang: links must point both ways
The Hreflang Generator validates language and region codes (ISO 639-1 languages, ISO 3166-1 alpha-2 regions) and warns when page A lists page B but B does not list A. That matches Google’s documentation, which asks for bidirectional links between language versions and notes it will still process the pairs that do point to each other if you leave some out.
Robots meta: a page blocked in robots.txt cannot be noindexed
The Robots Meta Tag Builder assembles directives such as noindex, nofollow, nosnippet and max-snippet. The most important rule sits with its companion, the robots.txt Generator: robots.txt controls crawling, the meta tag controls indexing, and if robots.txt disallows a page Google never fetches it, so any noindex on it is never seen. To keep a page out of the index, allow crawling and use noindex. An earlier version of this page said that noindex, nofollow “wastes crawl budget”; Google says nothing of the kind, and the combination is legitimate.
Internal links and URL slugs
The Internal Link Visualizer draws the link graph from a sitemap and pasted page HTML, flags orphan pages and shows click depth from the home page; it is a one-off audit of what you paste, not a crawler. The URL Slug Optimizer suggests slugs and warns about uppercase letters, underscores and query characters. On underscores Google is explicit: it recommends hyphens instead of underscores to separate words, because they help users and search engines identify the concepts in a URL. Changing a live URL later means a permanent 301 redirect, so choose once.
Headings: for readers first
The Heading Hierarchy Checker flags skipped levels, empty headings and multiple H1s. Those are accessibility issues before they are SEO issues: screen-reader users navigate by headings. Google’s SEO starter guide says headings in semantic order are fantastic for screen readers, but from Google Search’s perspective it does not matter if they are out of order. Fix the outline for people; do not expect a ranking change from it.
A workable order for a new page
- Headline Analyzer and URL Slug Optimizer for the title and URL.
- People Also Ask Generator and Related Keywords Extractor to plan coverage, then check real result pages.
- Write the page. Then Readability Score, Heading Hierarchy Checker and Featured Snippet Preview on the draft.
- Meta Description Generator and SERP Preview for the snippet.
- Canonical, plus hreflang and robots meta if needed.
- Structured data, then the checks in Six Checks Before You Publish.
Sources, checked October 12, 2026: Google: Featured snippets; Google: Control your snippets; Ahrefs: meta description rewrite study; Google: Consolidate duplicate URLs; Google: Localized versions (hreflang); Google: Robots meta tag; Google: URL structure; Google: SEO starter guide.