A technical SEO audit is a systematic review of your website's technical health — the infrastructure-level factors that determine whether search engines can crawl, index, and rank your pages effectively. Unlike content audits (which evaluate what you're saying) or backlink audits (which evaluate who's linking to you), a technical audit focuses on how your site is built and served.
Done well, a technical audit catches the invisible problems that silently drain your search performance: pages search engines can't find, content they can't render, signals that confuse them, and performance issues that frustrate users before they even read a word.
Here's how to run one from start to finish.
Step 1: Crawl your site
Everything starts with a crawl. A website crawler visits every accessible page on your site, following links the same way a search engine would, and records what it finds: URLs, status codes, page titles, meta descriptions, headings, internal links, images, canonical tags, and more.
The key considerations when setting up a crawl are scope (are you crawling the entire domain or a specific subdirectory?), JavaScript rendering (does your site rely on client-side rendering that requires a headless browser?), and authentication (do you need to crawl pages behind a login?).
For most audits, you want a full-domain crawl with JavaScript rendering enabled. IATO handles both in the cloud — enter your URL, enable JS rendering, and the crawl runs on our infrastructure. No local resources consumed, no browser left open.
Once the crawl completes, you'll have a complete dataset of every page your site exposes to crawlers.
Step 2: Check crawlability and indexability
The most fundamental question in technical SEO is: can search engines find and index your pages? Several factors affect this.
Robots.txt controls which pages crawlers are allowed to visit. Review your robots.txt file for overly broad disallow rules that might be blocking important content. A common mistake is leaving staging-environment robots.txt rules in place after launching a production site.
Meta robots tags control whether individual pages should be indexed. Look for pages that have noindex directives when they should be indexed, or pages that are missing noindex when they should be excluded (like thank-you pages or internal search results).
Canonical tags tell search engines which version of a page is the "official" one. Audit for pages with missing canonicals, pages that canonicalize to the wrong URL, and canonical chains (page A canonicalizes to page B, which canonicalizes to page C).
XML sitemaps list the pages you want search engines to index. Cross-reference your sitemap against your crawl data: are important pages missing from the sitemap? Does the sitemap include pages that are noindexed, redirected, or returning errors?
Step 3: Audit HTTP status codes
Status codes reveal the health of your URL structure. A clean site should be predominantly 200 (OK) responses, with minimal errors.
3xx redirects are not inherently bad, but redirect chains (multiple hops) waste crawl budget and dilute link equity. Identify any chains longer than one hop and consolidate them. Also look for redirect loops, where page A redirects to B and B redirects back to A.
4xx client errors mean pages that were expected to exist but don't. The most common is 404 (Not Found). A few 404s are normal, but a large number — especially on pages that have internal links pointing to them — indicates structural problems. Soft 404s (pages that return a 200 status but display a "not found" message) are particularly sneaky because search engines may not realize the page is gone.
5xx server errors indicate backend problems. These should be zero in a healthy site. If your crawl finds 5xx responses, investigate immediately — they mean some of your pages are intermittently or permanently broken.
Step 4: Review page-level SEO elements
With crawlability confirmed and status codes clean, audit the on-page elements that affect how search engines understand and display your content.
Title tags should be unique, descriptive, and under 60 characters. Flag duplicates (multiple pages with the same title), missing titles, and titles that are too long or too short.
Meta descriptions should be unique and under 160 characters. While not a direct ranking factor, they affect click-through rates from search results. Duplicate or missing descriptions are missed opportunities.
Heading hierarchy should follow a logical structure: one H1 per page that describes the main topic, followed by H2s for major sections, H3s for subsections, and so on. Look for pages with missing H1s, multiple H1s, or headings that skip levels (jumping from H1 to H4).
Image optimization covers alt attributes (present and descriptive?), file sizes (are images compressed?), and modern formats (WebP or AVIF instead of PNG/JPEG where possible).
Step 5: Analyze site structure and internal linking
Site structure affects both user experience and search engine crawling. Your audit should evaluate how pages connect to each other.
Crawl depth measures how many clicks it takes to reach a page from the homepage. Pages that are four or more clicks deep receive less crawl attention and less link equity. Identify important pages with high crawl depth and consider restructuring your internal linking to bring them closer to the surface.
Orphaned pages have no internal links pointing to them — they're only discoverable through the sitemap or direct URL access. These pages are effectively invisible to both users and search engines. Either link to them from relevant pages or consider whether they should exist at all.
Internal link distribution shows which pages receive the most and fewest internal links. Your most important pages (key landing pages, high-converting content) should have strong internal link support. If your audit reveals that your homepage links to 200 pages indiscriminately, consider a more strategic linking approach.
Step 6: Validate structured data
Structured data (Schema.org markup) helps search engines understand your content and can trigger rich results in SERPs — review stars, FAQ dropdowns, product prices, breadcrumbs, and more. A technical audit should validate both presence and correctness.
JSON-LD validation is the first check. Are your structured data blocks valid JSON? Malformed JSON-LD silently fails — search engines ignore it without any visible error on the page. Crawl your pages and parse each <script type="application/ld+json"> block to verify syntax.
Schema type coverage measures whether appropriate schema types are present on the right pages. Product pages should have Product schema. Blog posts should have Article or BlogPosting. FAQ sections should use FAQPage. Organization schema should appear site-wide. Missing schema on eligible pages means missed rich result opportunities.
Required property validation ensures each schema type includes its mandatory fields. A Product schema without name or offers won't generate rich results. An Article without datePublished or author loses eligibility for article-specific SERP features. Cross-reference your markup against Google's structured data documentation for each type.
Nesting and @id references matter for complex schemas. If your Organization schema references a logo or contactPoint, those nested objects need valid properties too. Use @id references consistently so search engines can connect related schema blocks across pages.
Step 7: Check hreflang and internationalization
For sites serving content in multiple languages or targeting multiple regions, hreflang implementation is a common source of technical debt.
Hreflang tag presence should be verified on every localized page. Each language/region variant should include hreflang tags pointing to all other variants, including itself (the self-referencing x-default or language-specific tag). Missing hreflang on even one variant can confuse search engines about which version to show in each market.
Return tag validation ensures that hreflang references are reciprocal. If your English page declares a Spanish variant, the Spanish page must declare the English page back. Non-reciprocal hreflang is the single most common implementation error, and search engines may ignore non-confirmed references entirely.
Language code accuracy matters more than most teams realize. en-us is not the same as en-US (hreflang is case-insensitive but follow ISO 639-1 for language and ISO 3166-1 Alpha-2 for region). Using incorrect codes means search engines won't recognize the targeting.
Step 8: Audit security and HTTPS implementation
HTTPS is a ranking signal, and mixed content or certificate issues silently erode trust signals.
Mixed content occurs when an HTTPS page loads resources (images, scripts, stylesheets) over HTTP. Modern browsers block mixed active content and warn on mixed passive content. Crawl for any http:// resource URLs loaded on HTTPS pages.
Certificate validity should be monitored. Expired certificates immediately trigger browser warnings that destroy user trust and can cause search engines to drop pages from the index. Check certificate expiration dates, chain completeness, and whether the certificate covers all subdomains your site uses.
HSTS headers (HTTP Strict Transport Security) tell browsers to always use HTTPS. If you've migrated to HTTPS, verify that HSTS headers are present and that the max-age is set to at least one year. Without HSTS, users who type your domain without https:// still make an initial insecure request.
Step 9: Evaluate page performance
Core Web Vitals and page speed directly affect both user experience and search rankings. While a full performance audit is its own discipline, your technical SEO audit should flag the most impactful issues.
Page size matters. Pages that transfer several megabytes of data will load slowly, especially on mobile connections. Identify your heaviest pages and investigate — usually the culprits are uncompressed images, unused JavaScript, or excessive third-party scripts.
Response time measures how quickly your server returns a response. Slow server response times affect every page on your site and are often caused by database queries, missing caches, or overloaded hosting.
Step 10: Prioritize and fix
An audit that identifies 500 issues but provides no prioritization is not useful. Categorize your findings by severity and impact.
Critical issues prevent pages from being crawled or indexed: robots.txt blocks on important content, widespread 5xx errors, broken canonical implementations, noindex on key pages. Fix these first.
High-impact issues affect ranking and user experience but don't prevent indexing: redirect chains, missing title tags, slow page load times, orphaned important pages. These are your next priority.
Low-impact issues are worth fixing but unlikely to move the needle individually: duplicate meta descriptions, minor heading hierarchy problems, alt text gaps. Batch these into maintenance work.
The most effective approach is to fix critical issues immediately, schedule high-impact issues for the current sprint, and add low-impact issues to your ongoing maintenance backlog.
Making audits a habit
A one-time audit is valuable. A regular audit practice is transformative. Technical SEO problems don't announce themselves — they accumulate quietly as content is published, pages are deleted, plugins are updated, and server configurations change.
Set up recurring crawls — weekly for high-traffic sites, monthly for smaller ones — and compare results over time. Watch for trend lines: is the number of broken links increasing? Are new redirect chains forming? Is crawl depth creeping up as content grows?
IATO's scheduled crawl monitoring and comparison features are designed for exactly this workflow. Set a schedule, and the platform alerts you when new issues appear.
Ready to audit your site? Start a free crawl with IATO — 500 pages, JavaScript rendering capability, comprehensive issue detection. Results in seconds, no credit card required.