The 20-Point SEO Audit Checklist (Ordered by Impact)

Most audit checklists list fifty items alphabetically, which quietly implies that alt text matters as much as a noindex tag. It doesn't. This checklist is ordered by consequence: fix in sequence and stop when you run out of time — you'll have handled the things that matter.

Tier 1: Catastrophic (fix today)

Each of these can remove you from search entirely.

1. Indexability. No noindex meta tag or X-Robots-Tag header on pages meant to rank. Check the raw HTML, not just your CMS setting.
2. robots.txt. No Disallow: / for User-agent: *. See the robots.txt guide for the patterns to look for.
3. HTTP status. Key pages return 200, not 404 or 5xx. Sounds obvious; broken redirects after migrations make it common.
4. Canonical tags. Each page canonicalises to itself, not to your homepage.
5. HTTPS. Valid certificate, with all HTTP traffic redirected to HTTPS.

Tier 2: High impact

6. Title tags. Present, unique, 15–60 characters, keyword near the front. See the title tag guide.
7. Meta descriptions. Present and unique on commercial pages, 50–160 characters.
8. One H1 per page, describing the actual topic.
9. Content depth. At least ~300 words of genuinely useful content on any page expected to rank.
10. Server response time under 600ms. See the TTFB guide.
11. Mobile viewport meta tag present — Google indexes mobile-first.
12. XML sitemap exists, is referenced in robots.txt, and is submitted in Search Console.

Tier 3: Meaningful gains

13. Internal linking. No orphan pages; important pages reachable within a few clicks of the homepage.
14. Structured data. Valid JSON-LD where applicable — Organization, Article, Product, FAQ. This is what earns rich results.
15. Image alt text on every meaningful image.
16. Heading hierarchy without skipped levels (h1 → h3).
17. Redirect chains collapsed to a single hop.
18. Mixed content. No http:// assets on HTTPS pages.

Tier 4: Polish

19. Open Graph and Twitter cards for shareable link previews.
20. Compression (gzip or brotli) enabled, and modern image formats where practical.

How to actually run it

Don't audit your whole site at once — you'll drown. Audit three pages: your homepage, your most important commercial page, and one blog post. Those three expose nearly every template-level problem you have, because issues almost always live in templates rather than individual pages.

Fix Tier 1 the same day you find it. Tier 2 within the week. Tiers 3 and 4 are steady background work.

Automate the tedious part

Every item in Tiers 1–4 above is machine-checkable, which is precisely what our free SEO checker does — it runs them against any URL and returns them grouped by severity, so you can work top-down without a spreadsheet. AI-search readiness (llms.txt, crawler access, FAQ structure) is in the AEO / GEO checker.