Technical SEO is the foundation everything else is built on. Without it, great content ranks poorly, structured data fails to parse, and AI systems struggle to understand your site. This checklist covers the 30 technical checks that matter most in 2026 — including new AI-readiness signals that didn't exist two years ago.
Crawlability and Indexation (Checks 1–8)
Before Google can rank your pages, it needs to find and understand them. Crawlability issues are silent killers — they don't throw errors in your browser, but they can prevent large portions of your site from ever appearing in search results.
Crawlability & Indexation
- robots.txt is present and correct — verify it isn't accidentally blocking critical pages or your entire site
- XML sitemap is submitted and up to date — includes all canonical pages, excludes noindex pages and pagination
- No orphan pages — every important page has at least one internal link pointing to it from a crawlable page
- Canonical tags are consistent — self-referencing canonicals on all pages; no conflicting canonicals between paginated or filtered pages
- No crawl traps — infinite URL spaces (faceted navigation, calendar archives, infinite scroll parameters) are blocked or handled
- 3xx redirects resolve in one hop — redirect chains longer than one step waste crawl budget and dilute link equity
- No 4xx or 5xx pages linked from navigable content — crawl your site monthly and fix or redirect broken links
- Crawl budget is not wasted on low-value URLs — session IDs, tracking parameters, and printer-friendly pages are excluded via robots.txt or canonical
Crawl budget matters most for sites with more than a few hundred pages. For smaller sites, focus on ensuring no critical pages are blocked and that your sitemap accurately reflects your site structure.
Page Speed and Core Web Vitals (Checks 9–14)
Google uses Core Web Vitals as a ranking signal. More importantly, slow pages convert worse — the correlation between page speed and bounce rate is consistent across every industry. These six checks cover the most impactful speed variables.
Speed & Core Web Vitals
- LCP under 2.5 seconds — measure in the field using Chrome UX Report data, not just lab tools
- INP under 200ms — test interaction responsiveness across page types, especially pages with complex JavaScript
- CLS under 0.1 — set explicit width/height attributes on images and videos; avoid inserting content above existing content after load
- TTFB under 800ms — server response time is the ceiling for everything downstream; upgrade hosting or add a CDN if needed
- Render-blocking resources eliminated or deferred — CSS and JS that block the initial render delay LCP; audit with Lighthouse
- Images are next-gen formats with lazy loading — WebP or AVIF with explicit dimensions and loading="lazy" on below-fold images
Mobile and UX (Checks 15–18)
Google indexes the mobile version of your site first. If your mobile experience is broken or degraded, your rankings reflect that — regardless of how polished your desktop site is.
Mobile & UX
- Mobile-friendly viewport is configured — <meta name="viewport" content="width=device-width, initial-scale=1"> is present on every page
- Tap targets are at least 48×48px — buttons and links that are too small cause usability failures that Google tracks via CrUX data
- No horizontal scrolling on mobile — content overflows and fixed-width elements are the most common cause
- Intrusive interstitials are absent — full-page popups that appear immediately on page load are penalized by Google's mobile interstitial penalty
Structured Data (Checks 19–23)
Schema markup is one of the highest-leverage technical SEO investments available in 2026. It improves how both Google and AI systems understand and represent your content. These five checks catch the most common implementation errors.
Structured Data
- JSON-LD is used (not Microdata) — JSON-LD is Google's preferred format and is dramatically easier to maintain
- Organization schema is present on the homepage — includes name, url, logo, sameAs (social profiles), and contactPoint
- Article/BlogPosting schema on all editorial content — includes author, datePublished, dateModified, and headline
- No validation errors in Google's Rich Results Test — required properties are present; no mismatches between schema values and visible content
- BreadcrumbList schema matches visible breadcrumbs — breadcrumb schema is one of the most impactful rich result types for click-through rate
AI Readiness Checks (Checks 24–30)
This category didn't exist in most technical SEO checklists before 2025. As AI answer engines become a significant discovery channel, your site's ability to be parsed, cited, and recommended by LLMs is a technical SEO concern — not just a content marketing concern.
AI Readiness
- Entity information is consistent across your site — your organization's name, founding year, description, and leadership are stated the same way everywhere they appear
- Author bios link to verifiable external profiles — LinkedIn, Google Scholar, or industry publication pages strengthen author entity authority
- Key facts are stated in plain, quotable sentences — LLMs extract claims that are clearly stated, not buried in complex prose or dependent on visual context
- FAQPage schema is present on high-intent pages — directly answers common questions in a format optimized for AI extraction
- Publication dates and last-updated dates are machine-readable — use ISO 8601 format in schema and <time> elements; freshness is a citation factor
- No content is gated behind JavaScript-only rendering — LLM crawlers and some search bots don't execute JavaScript; key information must be present in the HTML source
- SameAs properties link to authoritative external profiles — Wikipedia, Wikidata, LinkedIn, Crunchbase, and industry directories all reinforce entity recognition
How to Prioritize What You Fix First
Running through all 30 checks will typically surface multiple issues. The key is triaging them correctly so you spend effort where it produces the most ranking impact.
Fix immediately (blockers): anything that prevents crawling or indexation — robots.txt misconfiguration, canonical errors, noindex on important pages, crawl traps. These issues can suppress entire sections of your site from search results regardless of content quality.
Fix within a sprint (high-impact): Core Web Vitals failures, missing Organization and Article schema, broken internal links. These have direct, measurable effects on rankings and rich result eligibility.
Fix as capacity allows (optimization): AI readiness checks, breadcrumb schema, image optimization for already-fast pages. These improve performance at the margin and build toward long-term LLMO authority.
The most efficient approach is to run an automated audit that checks all 30 of these signals in one pass and prioritizes findings by impact — rather than working through a manual checklist page by page.
Related Articles
Run Seraph to audit all 30 of these checks automatically. Every finding comes with an LLM-ready fix prompt — no manual checklist required.
Start your free audit →