Technical SEO is the foundation everything else is built on. You can publish exceptional content, earn authoritative backlinks, and optimize every headline — but if search engines can't properly crawl, index, and understand your site, none of it matters. Technical issues are particularly dangerous because they're invisible to the naked eye. Your site looks fine to visitors. Rankings are quietly suffering.
A technical SEO audit is a systematic examination of every factor that affects how search engines interact with your site. This guide walks through each major category: what it covers, why it matters, and what to look for.
Crawlability: Can Search Engines Reach Your Pages?
Crawlability is the starting point. Before a page can rank, a search engine crawler must be able to reach it. Surprising numbers of pages fail this basic test — not because of anything dramatic, but because of small configuration errors that accumulate over time.
robots.txt is the first place to check. This file tells crawlers which sections of your site to skip. A misconfigured robots.txt — perhaps one that was set up to block a staging environment and accidentally made it to production — can disallow your entire site from being crawled. One line in the wrong file has wiped entire sites from Google's index.
Noindex tags can also prevent pages from appearing in search results even after they're crawled. The distinction matters: a page can be crawled but not indexed if a <meta name="robots" content="noindex"> tag is present. Audit every template to ensure noindex tags aren't being applied globally or to pages that need to rank.
Canonical issues are subtler. A canonical tag tells Google which version of a URL is the "official" one. When canonical tags point to wrong URLs — whether because of a CMS bug, a copy-paste error, or an outdated redirect — you end up with pages competing against themselves or effectively telling Google to ignore them.
Crawl budget becomes critical on larger sites. Google allocates a finite number of crawl requests to each site based on its authority and server capacity. Sites with extensive redirect chains, infinite scroll implementations, URL parameters generating thousands of near-duplicate URLs, or large numbers of broken links waste crawl budget that should be spent on valuable pages.
Indexability: Are Your Pages Being Indexed?
Crawlability and indexability are related but distinct. A page can be crawled and still not be indexed. Search indexability determines whether Google actually stores a page in its index and makes it eligible to rank.
The canonical tool for checking indexability is Google Search Console's Index Coverage report. It divides your pages into categories: Indexed, Not Indexed, and various error states. The "Excluded" section is where most problems hide — pages that Google crawled but chose not to include, often with explanations like "Duplicate, submitted URL not selected as canonical" or "Crawled — currently not indexed."
Key indexability blockers include:
- Noindex directives in meta tags or HTTP headers
- Canonical pointing elsewhere — telling Google a different URL is the authoritative version
- Thin or duplicate content — Google may crawl the page but decide it doesn't add enough value to index
- Soft 404 responses — pages that return a 200 HTTP status but contain error messages ("product not found," "no results") that Google treats as empty pages
- Slow server response times — if your server is slow enough, Googlebot may give up before the page loads
Monitoring index coverage should be an ongoing practice, not a one-time check. Pages fall out of the index silently, and the only way to catch it is to look regularly.
Page Speed & Core Web Vitals
Page speed graduated from a "best practice" to a confirmed ranking signal years ago, and its importance has only grown. Google's Core Web Vitals are now embedded in the ranking algorithm, measuring three dimensions of real-world loading experience:
LCP (Largest Contentful Paint) measures how quickly the main content of a page becomes visible. For most pages, this is the hero image or the primary heading. An LCP above 2.5 seconds is considered poor. Common culprits include large unoptimized images, render-blocking resources, and slow server response times.
INP (Interaction to Next Paint) replaced FID in 2024 and measures how quickly the page responds to user inputs like clicks and taps. A poor INP score (above 500ms) usually indicates heavy JavaScript execution blocking the main thread.
CLS (Cumulative Layout Shift) measures visual stability — how much page elements move around while loading. Ads that load late, images without declared dimensions, and dynamically injected content above existing content all contribute to high CLS scores. A score above 0.1 is considered poor.
AI SEO Scanner's Core Web Vitals monitoring tracks these metrics across your pages over time, flagging regressions as they happen rather than waiting for ranking drops to alert you.
Structured Data & Schema Markup
Structured data is one of the most consistently underutilized technical SEO opportunities. JSON-LD schema markup gives search engines explicit, machine-readable information about your content — and in return, you get a shot at rich results: star ratings in search snippets, FAQ accordions directly in results, product pricing and availability, how-to steps, event dates, and more.
From a technical audit perspective, the key checks are:
- Presence — does the page have any schema markup at all?
- Validity — does the schema pass Google's Rich Results Test without errors or warnings?
- Relevance — is the schema type appropriate for the content? (Product schema on a blog post is ignored; Article schema on a product page wastes an opportunity.)
- Completeness — are required properties present? Missing required fields prevent rich results from triggering even if the schema is otherwise valid.
Common errors include referencing images that don't exist, mismatched @type values, and schema that was valid last year but has been deprecated in favor of newer properties.
Internal Link Architecture
Internal links are how PageRank flows through your site. Pages that receive many internal links from authoritative parent pages tend to rank better than pages that are buried three or four clicks deep with few links pointing to them.
Siloing is the practice of organizing your internal link structure so that thematically related pages link to each other densely, creating topical clusters that signal expertise to search engines. A well-siloed site has clear content hubs with strong internal linking between related articles.
Anchor text matters for internal links just as it does for backlinks. Generic anchors like "click here" or "read more" waste the opportunity to reinforce keyword relevance. Descriptive, keyword-rich anchor text — used naturally — helps search engines understand the topic of the linked page.
Orphan pages — pages with no internal links pointing to them — are a silent ranking problem. Crawlers discover pages by following links. If no page on your site links to a given URL, crawlers may never find it. Orphan pages appear in audits when you import your sitemap and compare it to crawl results: pages in the sitemap that the crawler couldn't reach via links.
A Practical 6-Step Audit Checklist
Use this checklist as a starting framework for your next technical audit:
-
Submit your XML sitemap to Google Search Console — Verify it's up to date, includes all canonical URLs, and excludes noindex pages. A sitemap with thousands of noindexed URLs wastes crawl budget and confuses coverage reporting.
-
Crawl your site with an audit tool — A full crawl discovers pages, captures on-page elements, identifies broken links and redirects, and flags technical issues automatically. The crawl is the foundation everything else is built on.
-
Audit and fix redirect chains — Every additional hop in a redirect chain (A → B → C instead of A → C) adds latency and dilutes link equity. Flatten chains so redirects resolve in a single hop wherever possible.
-
Check canonical tags site-wide — Verify that every page either has a valid self-referencing canonical or correctly points to the preferred version. Canonical mismatches are common after migrations and template changes.
-
Validate structured data — Run your key page templates through Google's Rich Results Test. Fix any errors, then check whether eligible pages are actually appearing in rich results via Search Console.
-
Test page speed on mobile — Use real-device testing, not just desktop emulation. Mobile Core Web Vitals are what Google uses for ranking, and mobile performance often lags significantly behind desktop results.
Technical SEO is not a one-time project — it's an ongoing operational discipline. The sites that hold rankings long-term are the ones that monitor technical health continuously, not the ones that do a big audit once a year and move on.
AI SEO Scanner's Full Site Audit automates all of these checks, running them across your entire site and presenting results in a prioritized, actionable format. Start auditing your site today and get a complete picture of your technical health in minutes.