The Technical SEO Audit Checklist

Great content will not rank if search engines cannot crawl it, understand it, or serve it quickly. Technical SEO is the infrastructure layer that makes everything else possible: your content strategy, your link building, your on-page optimization. When the foundation has cracks, the entire structure underperforms.

A technical SEO audit systematically evaluates every aspect of your site's infrastructure that affects search engine visibility. This checklist covers what to check, why it matters, and how to fix the most common issues.

Crawlability

If search engines cannot discover and access your pages, nothing else matters. Crawlability is the first thing to audit.

Robots.txt

• Verify your robots.txt is accessible at yourdomain.com/robots.txt. A missing or misconfigured file can block crawlers from your entire site.
• Check for overly broad disallow rules that might accidentally block important sections. A common mistake is disallowing /admin/ with a pattern that also catches /admin-guides/.
• Confirm your XML sitemap is referenced in the robots.txt file.
• Test with Google's robots.txt tester in Search Console to verify that important URLs are not blocked.

XML Sitemaps

• Ensure your sitemap exists and is valid XML. Parse errors will prevent search engines from processing it.
• Include only indexable URLs: No 404s, no redirects, no noindexed pages. Every URL in the sitemap should return a 200 status and be the canonical version.
• Keep sitemaps under 50,000 URLs / 50MB. Use a sitemap index file for larger sites.
• Include lastmod dates and keep them accurate. Search engines use these to prioritize crawling.
• Submit sitemaps to Google Search Console and Bing Webmaster Tools.

Internal Link Structure

• Identify orphan pages: Pages with no internal links pointing to them are unlikely to be crawled or ranked. Run a crawl and compare the results against your sitemap to find pages that exist but are not linked.
• Check crawl depth: Important pages should be reachable within three clicks from the homepage. Pages buried six or seven levels deep get crawled less frequently.
• Fix broken internal links: Every 404 link is wasted crawl budget and a dead end for users.
• Ensure logical link hierarchy: Your most important pages should receive the most internal links.

Crawl Budget

For large sites (10,000+ pages), crawl budget becomes a factor:

• Remove or noindex low-value pages (empty tag pages, thin filter combinations, outdated content) to focus crawl budget on content that matters.
• Fix server errors and slow responses that waste crawl budget on failed requests.
• Monitor crawl stats in Google Search Console under Settings > Crawl Stats to understand how Google is spending its budget on your site.

Indexation

Getting crawled is step one. Getting indexed is step two. An indexation audit checks that the right pages appear in search results and the wrong ones do not.

Index Coverage

• Check the Pages report in Google Search Console for errors, warnings, and excluded pages.
• Compare indexed page count (site:yourdomain.com) against your expected count. A significant gap in either direction indicates a problem.
• More pages indexed than expected: Duplicate content, parameter URLs, or thin pages that should be noindexed.
• Fewer pages indexed than expected: Crawlability issues, noindex tags, or quality signals causing Google to decline indexing.

Canonical Tags

• Verify every page has a self-referencing canonical tag unless it intentionally points to a different canonical.
• Check for conflicting signals: A page that is canonicalized to another URL but also appears in the sitemap sends mixed signals.
• Ensure canonical tags use the correct protocol and domain (https vs. http, www vs. non-www).
• Audit pages with cross-domain canonicals to confirm they are intentional.

Meta Robots and X-Robots-Tag

• Search for unintentional noindex tags across your site. A single misplaced noindex can remove a critical page from search results.
• Check HTTP headers for X-Robots-Tag directives that may not be visible in the HTML source.
• Verify nofollow is not applied to internal links you want search engines to follow.

Duplicate Content

• Identify duplicate or near-duplicate pages that could cause keyword cannibalization.
• Check for www/non-www and http/https variations that resolve to different pages instead of redirecting.
• Audit URL parameters that create duplicate versions of the same content (sorting, filtering, session IDs).
• Verify pagination is handled correctly with proper rel=prev/next or consolidated view pages.

Site Performance and Core Web Vitals

Page speed is a ranking factor, and Core Web Vitals are Google's specific metrics for measuring user experience.

Core Web Vitals

• Largest Contentful Paint (LCP): Should be under 2.5 seconds. Common fixes include optimizing hero images, preloading critical resources, and improving server response time.
• Interaction to Next Paint (INP): Should be under 200 milliseconds. Reduce JavaScript execution time, break up long tasks, and optimize event handlers.
• Cumulative Layout Shift (CLS): Should be under 0.1. Set explicit dimensions on images and embeds, avoid inserting content above existing content, and use CSS containment.

Performance Fundamentals

• Server response time (TTFB): Should be under 800ms. If slow, investigate hosting, caching, and database query performance.
• Enable compression: Verify Gzip or Brotli compression is active for text-based resources.
• Leverage browser caching: Set appropriate Cache-Control headers for static assets.
• Minimize render-blocking resources: Defer non-critical JavaScript and inline critical CSS.
• Optimize images: Use modern formats (WebP, AVIF), appropriate dimensions, and lazy loading for below-the-fold images.
• Minimize third-party scripts: Audit tag managers and third-party scripts that add latency.

Measurement

• Use PageSpeed Insights for page-level diagnostics (lab data + field data).
• Check the Core Web Vitals report in Search Console for site-wide field data grouped by URL pattern.
• Monitor real user metrics through GA4 or a dedicated performance monitoring tool.

Structured Data

Structured data helps search engines understand your content and can earn rich results (review stars, FAQ accordions, breadcrumb trails) that increase click-through rates.

Implementation Checks

• Validate all structured data with Google's Rich Results Test and Schema.org validator.
• Use JSON-LD format (Google's recommended approach) rather than Microdata or RDFa.
• Ensure required properties are present for each schema type you implement.
• Check for warnings in Search Console's Enhancements reports.

Common Schema Types

Audit whether these are implemented where appropriate:

• Organization: Company name, logo, contact information, social profiles.
• Breadcrumb: Navigation path matching your visible breadcrumb UI.
• Article/BlogPosting: For editorial content with author, date, and headline.
• FAQ: For pages with question-and-answer content.
• Product: For e-commerce with price, availability, and reviews.
• LocalBusiness: For businesses with physical locations.
• HowTo: For instructional content with defined steps.

Mobile-First Indexing

Google indexes and ranks based on the mobile version of your site. A mobile audit is not optional.

Mobile Parity

• Content parity: Verify that all content visible on desktop is also present on mobile. Hidden tabs or accordions are fine as long as the content is in the DOM.
• Metadata parity: Title tags, meta descriptions, and structured data should be identical across mobile and desktop.
• Internal links: Ensure mobile navigation includes the same internal links as desktop.

Mobile Usability

• Responsive design: Pages should adapt to all screen sizes without horizontal scrolling.
• Tap targets: Buttons and links should be at least 48x48 CSS pixels with adequate spacing.
• Font sizes: Body text should be at least 16px without requiring zoom.
• No intrusive interstitials: Avoid pop-ups that cover the main content on mobile, especially on landing pages from search.
• Check the Mobile Usability report in Search Console for flagged issues.

International SEO

If your site serves multiple languages or regions, additional technical requirements apply.

Hreflang Implementation

• Add hreflang annotations for every language/region variant. Each page must reference all its alternates, including itself.
• Ensure hreflang is reciprocal: If page A references page B as an alternate, page B must reference page A.
• Include an x-default tag that points to the default or language-selector page.
• Validate hreflang with a dedicated checker to catch missing return links and incorrect language codes.

URL Structure

Choose and implement one approach consistently:

• Subdirectories (/en/, /fr/): Easiest to maintain, shares domain authority.
• Subdomains (en.example.com): More separation, requires more authority building.
• ccTLDs (example.fr): Strongest geo-targeting signal, highest maintenance cost.

HTTPS and Security

• Verify your entire site is served over HTTPS with no mixed content warnings.
• Check certificate validity and expiration dates.
• Ensure HTTP-to-HTTPS redirects are in place for all pages (301, not 302).
• Implement HSTS headers to prevent protocol downgrade attacks.
• Scan for mixed content: Resources (images, scripts, stylesheets) loaded over HTTP on HTTPS pages.

Running the Audit

A technical SEO audit produces the most value when you can see your entire site's structure and health in one place. Checking these items page by page is impractical for any site with more than a few dozen URLs.

Evergreen streamlines this process. Crawl your site to map every URL, its status codes, metadata, and internal link relationships. The visual sitemap shows you structural issues like orphan pages and excessive depth at a glance. Layer in your Google Search Console data to see which indexation and performance issues are affecting real search traffic, and use GA4 correlation to prioritize fixes by business impact.

Instead of assembling data from five different tools into a spreadsheet, you get a unified view of your site's technical health alongside the content and performance data that helps you decide where to focus first. Start with a crawl and let the audit data guide your priorities.