The Complete Technical SEO Checklist for 2026

Most websites lose rankings before a single keyword is ever targeted. Slow pages, broken architecture, crawl traps, pages Google never indexes — the leaks are invisible until you measure them. Technical SEO plugs those leaks so every other effort actually compounds. Here is the checklist I run on every project, in priority order.

01Crawlability & indexation

If Google can't crawl and index a page, nothing else matters. This is always where I start. The goal is simple: make sure the pages that should rank are discoverable and indexable, and the ones that shouldn't are kept out of the index entirely.

Robots, sitemaps and indexation control

Audit your robots.txt for accidental blocks, keep a clean XML sitemap of only canonical, indexable URLs, and use noindex deliberately — not robots.txt — to keep thin pages out of search. A page blocked in robots can still be indexed without its content, which is the worst of both worlds.

02Site architecture & internal linking

Architecture is the most under-rated ranking lever there is. A flat, logical structure where important pages sit within three clicks of the homepage lets authority flow exactly where you want it. Deep, tangled hierarchies bury your best content.

Internal links are how you tell Google what matters. Link from high-authority pages to the pages you want to rank, use descriptive anchor text, and build genuine topic clusters — a pillar page linking to and from its supporting articles.

Your internal linking is a map of what you think is important. Make sure it points at the pages that make you money.

— Rule #1 of every audit

03Core Web Vitals & performance

Speed is both a ranking factor and a conversion factor. The three Core Web Vitals — LCP, INP and CLS — measure loading, interactivity and visual stability. As of 2024, INP replaced FID, so if your audit still references FID, it's out of date.

• LCP under 2.5s — optimise your largest image or text block; preload it, serve modern formats, and cut render-blocking resources.
• INP under 200ms — reduce heavy JavaScript and long tasks on the main thread so the page responds instantly to input.
• CLS under 0.1 — reserve space for images, ads and embeds so nothing jumps as the page loads.

04Mobile & rendering

Google indexes the mobile version of your site, full stop. If content, links or structured data exist only on desktop, they effectively don't exist. Verify parity between mobile and desktop, and confirm that JavaScript-rendered content is actually visible to Googlebot — test the rendered HTML, not just the source.

For JavaScript-heavy sites, prefer server-side rendering or static generation for anything that must rank. Client-side rendering puts your content behind a second crawl queue you don't control.

05Structured data & canonicalization

Structured data won't rank you on its own, but it earns rich results — stars, FAQs, breadcrumbs, prices — that lift click-through rates and increasingly feed AI answer engines. Use JSON-LD, validate every type, and only mark up content that's actually visible on the page.

Canonicalization is the other half: every piece of content should have one canonical URL. Consolidate www/non-www, http/https, trailing slashes and parameter variants so you never split signals across duplicates.

06Where to start tomorrow

Don't try to fix everything at once. Pull your indexation report first — if Google isn't indexing your money pages, that's your fire. Then Core Web Vitals, then architecture and internal links. Structured data and the long tail come after the foundation is solid.

Technical SEO isn't glamorous, but it's the multiplier on everything else you do. Get the foundation right and your content and links finally pull their full weight. Want a real audit of your site against this checklist? Request a free audit — I'll send back the priorities that matter for your specific situation.