The Ultimate Technical SEO Audit Checklist for 2025

2025-09-12 • RedSun IT Services

A technical SEO audit is essentially a health check for your website’s backend. It inspects the infrastructure (site architecture, speed, security, etc.) that affects how Google crawls, indexes, and ranks your pages. In practice, this audit will uncover hidden issues – broken links, missing meta tags, slow scripts or images – that silently block your site from ranking higher.

For 2025, this is more important than ever: Google now emphasizes user experience signals (like Core Web Vitals) and mobile-first indexing, so any technical flaw can hurt your SEO. Use the checklist below to systematically fix common problems and boost your site’s visibility. By following this technical SEO audit checklist, you can enhance your website SEO performance immensely.

Crawlability & Indexing

Robots.txt & Indexing: Check that your robots.txt isn’t accidentally blocking important sections of your site, and that you’re not using noindex tags on key pages. Ensure an up-to-date XML sitemap is submitted in Google Search Console so crawlers find all important URLs.

Fix Crawl Errors: Use Google Search Console or crawling tools (e.g., Screaming Frog, Semrush) to spot crawl errors, 404s, and broken links. According to one study, ~52% of sites have broken links – these should be fixed or 301-redirected. Resolving crawl errors ensures Google can index every page you want in search.

Site Architecture & Internal Links

URL Structure: Use short, descriptive URLs with hyphens and relevant keywords (e.g., yourdomain.com/services/seo-audit). Clear URLs help search engines and users understand page content.

Site Structure: Keep your site “flat” and logical – all important pages should be reachable within 3–4 clicks of the homepage. Avoid orphan pages (pages with no incoming links).

Internal Linking: Link related pages with descriptive anchor text to pass authority and help crawlers discover content. Good internal links and breadcrumb navigation improve site hierarchy and user experience.

Page Speed & Core Web Vitals

Core Web Vitals: Optimize for Google’s performance metrics. Aim for Largest Contentful Paint (LCP) < 2.5s, Interaction to Next Paint (INP) < 200ms (formerly FID), and Cumulative Layout Shift (CLS) < 0.1. Google uses these metrics as ranking factors, so meeting these thresholds is critical. In fact, one study found 96% of websites had at least one page failing Core Web Vitals tests.

Speed Optimizations: Compress and resize large images, minify CSS/JavaScript, and enable browser caching or a CDN. Simple steps like compressing images and using a CDN can dramatically improve load times and rankings. Run your pages through Google PageSpeed Insights to identify and fix the biggest bottlenecks first (images, unused scripts, etc.).

Mobile-Friendliness

Responsive Design: Google uses the mobile version of your site for indexing, so make sure your layout adapts to all screen sizes. Use Google’s Mobile-Friendly Test to catch issues. Ensure text is legible without zooming, and touch elements (buttons/links) are well-spaced.

Mobile UX: Check that no content is wider than the viewport and that fonts are large enough. Avoid intrusive interstitials (full-screen popups) on mobile, since Google penalizes those for poor user experience. A smooth mobile experience helps both users and rankings.

Security (HTTPS) & Accessibility

HTTPS: Ensure every page loads securely over HTTPS with a valid SSL certificate. Redirect all HTTP traffic to HTTPS and fix any “mixed content” issues (insecure scripts or images). Google and users favor secure sites, so a proper HTTPS implementation is now a baseline ranking factor.

Site Accessibility: Make sure search engines can crawl key assets (CSS/JS) and that images have descriptive alt text. Check that your site works with minimal reliance on scripts or that any JavaScript rendering is handled appropriately. This improves crawlability and accessibility for both bots and users.

Structured Data & Duplicate Content

Schema Markup: Implement structured data (e.g., Article, Product, FAQ schema) where relevant to enable rich results in Google. Use Google’s Rich Results Test to validate your markup. Focus on key types like Products or FAQs, and correct any schema errors or warnings. A clean, error-free schema can boost your visibility in search.

Canonicalization: Add self-referencing <link rel="canonical"> tags on each page to indicate the preferred URL and prevent duplicate-content issues. For pages with query parameters or printer-friendly versions, use canonicals to consolidate indexing. Also, ensure you don’t index multiple versions of the same page (www vs non-www, HTTP vs HTTPS). Proper canonicals keep your link equity focused on the right URLs.

Other Aspects for Technical SEO Audit Checklist

• Robots & Tags: Revisit robots.txt and <meta> robots tags to ensure only unwanted pages are excluded. A small robots.txt mistake can block critical pages.
• Breadcrumbs & Navigation: For large sites, use breadcrumb schema/navigation to help Google understand your hierarchy.
• Log File Analysis (Advanced): Analyze server logs to see how Googlebot is crawling your site and fix any crawl-budget waste (e.g., bot hitting paginated or duplicate pages excessively).

Following this technical SEO audit checklist will help you uncover and fix the hidden issues holding back your rankings. By ensuring crawlability, a logical site structure, fast page speed, mobile usability, security (HTTPS), and proper schema/canonicals, you’ll improve both user experience and SEO. Regular audits (especially after major site changes or Google updates) keep your site healthy and competitive.