Technical SEO Audit Checklist (2026)

A technical SEO audit checks whether search engines and AI answer engines can crawl, render, and index your site cleanly — before a single word of content gets judged on merit. Get it wrong and your best pages stay invisible no matter how good they are. This is a prioritised 2026 checklist, grouped from the highest-leverage fixes down, with why each item matters and exactly how to check it.

How to work through this audit

Work top to bottom, because the groups are ordered by leverage. A single blocked rule in robots.txt can bury an entire domain, so crawlability comes first; one missing hreflang tag usually affects only a single market, so international targeting comes last. Your core toolkit is Google Search Console, a crawler such as Screaming Frog or Sitebulb, PageSpeed Insights and the CrUX dataset for field data, and Google's Rich Results Test for schema. Fix the highest group before you move down — there is no point tuning Core Web Vitals on a page Google is not allowed to index.

1. Crawlability & indexation

This is the foundation. If a page cannot be crawled and indexed, nothing else on this list matters. Start here every time.

• robots.txt. Why it matters: one stray Disallow can block whole sections and even CSS or JS the renderer needs. How to check: open /robots.txt, confirm you are not blocking key directories or assets, and test specific URLs in Search Console.
• XML sitemap. Why: it tells engines which URLs you consider canonical and want indexed. How to check: submit it in Search Console and confirm it lists only indexable, 200-status URLs — no redirects, no noindex, no 404s — keeping each file under 50,000 URLs.
• Canonical tags. Why: they consolidate duplicate and parameterised URLs onto one authoritative version. How to check: crawl the site and confirm each rel=canonical points to a live, intended URL — not to a redirect, a noindex page, or the wrong protocol.
• Noindex directives. Why: an accidental noindex is one of the fastest ways to drop pages from Google, and a common leak when a staging site goes live. How to check: crawl for meta robots and X-Robots-Tag headers and confirm nothing you want ranked is set to noindex.
• Redirects. Why: chains and loops waste crawl budget and leak link equity. How to check: crawl for 3xx status codes, collapse chains to a single hop, and make sure permanent moves use a 301 rather than a 302.
• Orphan pages. Why: pages with no internal links are hard to discover and signal low importance. How to check: compare your crawl's internal-link graph against your sitemap and server logs — anything in the sitemap but unlinked is orphaned. A deliberate internal linking strategy fixes this at the root.

2. Site architecture & URLs

A shallow, logical structure helps both crawlers and users, and it decides how authority flows through the site.

1. Flat depth. Keep important pages within three clicks of the home page; deeper pages get crawled less often. Check click depth in your crawler.
2. Clean URLs. Use short, lowercase, hyphenated, descriptive slugs with no session IDs or tracking parameters. Watch for parameter bloat and duplicate variants in the Pages report.
3. Logical hierarchy. Group content into clear topical directories (/services/, /journal/) so users and engines understand the relationships. Review the folder structure and breadcrumb trail.
4. Internal linking. Link from high-authority pages to priority targets using descriptive anchor text, and strengthen the pages receiving the fewest internal links.

3. Performance & Core Web Vitals

Speed is a confirmed ranking factor and a heavy influence on conversions. Google grades three field metrics, and you need to pass all three at the 75th percentile of real users:

• Largest Contentful Paint (LCP) — main content should render within 2.5 seconds. Fix by optimising and preloading your largest image or text block and improving server response time.
• Interaction to Next Paint (INP) — should stay under 200 ms. This replaced First Input Delay in 2024; fix by trimming and deferring the JavaScript that blocks the main thread.
• Cumulative Layout Shift (CLS) — should stay under 0.1. Fix by setting width and height on images and reserving space for ads and embeds so nothing jumps.

Check field data in the Core Web Vitals report in Search Console and in PageSpeed Insights (which reads the real-user CrUX dataset), then use Lighthouse for lab diagnostics. For the full breakdown, see my Core Web Vitals guide.

4. Structured data

Schema markup does not directly boost rankings, but it makes content machine-readable, unlocks rich results, and is increasingly how AI answer engines parse and cite you.

• Use the right types. Apply Article, FAQPage, Product, BreadcrumbList, Organization, or LocalBusiness schema as relevant, in JSON-LD.
• Validate it. Run every template through Google's Rich Results Test and the Schema.org validator, and clear errors and warnings before shipping.
• Keep it truthful. Marked-up content must match what users actually see — mismatches risk a manual action.
• Monitor enhancements. Watch the Enhancements reports in Search Console for schema errors that quietly disable rich results.

For a deeper walkthrough, see my guide to schema markup for SEO.

5. Mobile

Google indexes the mobile version of your site by default, so the mobile experience is the experience that ranks.

• Responsive design. Serve the same HTML to every device with a flexible layout. Test it in the device view in Chrome DevTools.
• Content parity. Make sure mobile shows the same content and structured data as desktop — anything stripped or hidden on mobile may not be indexed.
• Tap targets & viewport. Confirm a proper viewport meta tag, legible font sizes, and buttons that are not crowded too close together.

6. HTTPS & security

• Valid HTTPS everywhere. HTTPS is a ranking signal; confirm the certificate is valid and unexpired, and scan for mixed-content warnings where HTTP assets load on an HTTPS page.
• Force one protocol and host. 301-redirect all HTTP URLs to HTTPS and pick a single canonical host (www or non-www) so you are not splitting signals.
• Security headers. Add HSTS and a sensible Content-Security-Policy; they harden the site and signal a well-maintained domain.

7. International targeting (hreflang)

If you serve multiple languages or regions, hreflang tells Google which version to show which users. It is fiddly and error-prone, which is why it sits last — but on a multi-market site it still matters.

• Reciprocal return tags. Every annotation must point both ways — if page A references B, B must reference A.
• Correct codes. Use valid ISO language and region codes (for example en-GB, es-MX) and include an x-default for the fallback.
• Check for errors. Use a crawler's hreflang report to catch missing return tags, invalid codes, and pages pointing at non-canonical URLs.

The audit at a glance

Working with me

A technical audit is only useful if the fixes actually ship. I run full technical SEO audits and then implement them — resolving crawl and indexation issues, rebuilding site architecture and internal linking, passing Core Web Vitals, and hardening structured data — as one connected job rather than a PDF of recommendations you have to hand off to someone else. If your search presence needs a rebuild from the technical foundation up, that's the SEO reboot. Tell me in one paragraph what's going wrong — pages not indexing, traffic sliding, a migration that tanked — and I'll tell you honestly which fixes move the needle first.