The technical SEO checklist for 2026

Technical SEO is the foundation: content cannot rank if crawlers cannot reach, render or trust it. Work through this list from top to bottom — the first items can block everything else.

1. Crawling & indexing (blockers)

• The home page returns HTTP 200 and is not noindex.
• robots.txt does not block the site, CSS or JavaScript, and lists your sitemap.
• Important pages are indexable; thin or private pages are intentionally noindex.
• Missing URLs return a real 404 or 410, not a “soft 404” with status 200.

2. One version of every page

• HTTPS everywhere with a valid certificate; http:// redirects with a single 301.
• Choose www or non-www and redirect the other.
• Self-referencing canonical tags on every indexable page; canonicals point to 200 URLs.
• Avoid indexable parameter URLs (sorting, tracking, sessions).

3. Site structure

• Every important page is within three clicks of the home page.
• No orphan pages — each one receives internal links.
• Internal links point to final URLs, not redirects or broken pages.
• Breadcrumbs on deeper pages, marked up with BreadcrumbList.

4. Sitemaps

• An XML sitemap with only canonical, indexable 200 URLs.
• Submitted in Google Search Console and Bing Webmaster Tools.
• Large sites: split by type with a sitemap index.

5. Speed & mobile

• Core Web Vitals in the “good” range: LCP ≤ 2.5 s, INP ≤ 200 ms, CLS ≤ 0.1.
• Compression (Brotli/Gzip), long cache lifetimes for static files, images in WebP/AVIF with width and height.
• A responsive layout with a viewport meta tag and readable text.

6. Rendering

• Main content present in the HTML response (server-side rendering or pre-rendering).
• No important content loaded only on user interaction.

7. International

• <html lang> on every page; correct, reciprocal hreflang with x-default for multilingual sites.

8. Structured data & security

• Valid JSON-LD: Organization and WebSite on the home page, Article, Product, BreadcrumbList where relevant.
• Security headers (HSTS, X-Content-Type-Options, frame protection, Referrer-Policy); no mixed content.

The BoostSEO audit checks all of the above automatically and sorts the results by impact so you know what to fix first.