Technical SEO: under the hood
Technical SEO ensures search engines can efficiently crawl, index, and understand your site. Master Core Web Vitals, structured data, site architecture, and more — the backend work that makes rankings possible.
Core Web Vitals explained
Google's three key performance metrics that directly impact rankings. Measure, optimize, and monitor these continuously.
Largest Contentful Paint
Measures loading performance. The largest element on the page (usually an image or hero block) should render within 2.5 seconds.
Interaction to Next Paint
Measures interactivity and responsiveness. How quickly the page responds to user input like clicks and key presses.
Cumulative Layout Shift
Measures visual stability. Elements should not jump or shift as the page loads. Unexpected layout shifts frustrate users.
The six pillars of technical SEO
Each pillar is critical. Weakness in any one area can hold back your entire site's performance in search.
Crawlability & Indexability
Can search engines find and store your pages? This is the foundation of technical SEO — if Google cannot crawl your site, nothing else matters.
- Robots.txt controls which pages bots can access
- XML sitemaps list all important URLs for crawlers
- Canonical tags prevent duplicate content issues
- Noindex tags exclude pages from the index
- Crawl budget optimization for large sites
Site Architecture
A logical, flat site structure helps both users and search engines navigate your content efficiently. Aim for no more than 3-4 clicks from homepage to any page.
- Flat hierarchy with clear categories
- Breadcrumb navigation on every page
- Internal linking distributes authority
- URL structure is clean and descriptive
- Faceted navigation handled correctly
Structured Data
Schema markup helps search engines understand your content and unlock rich results — star ratings, FAQs, breadcrumbs, and more in search snippets.
- JSON-LD is the recommended format
- Organization, Article, Product, FAQ schema
- Breadcrumb schema for navigation
- Validate with Google Rich Results Test
- Keep schema updated as content changes
Mobile Optimization
Google uses mobile-first indexing, meaning the mobile version of your site is the primary version for ranking. A broken mobile experience means broken rankings.
- Responsive design adapts to all screen sizes
- Tap targets are at least 48x48 pixels
- No intrusive interstitials on mobile
- Font sizes are readable without zooming
- Viewport meta tag is properly configured
Page Speed
Fast pages rank better, convert better, and provide better user experience. Every second of load time costs you visitors and revenue.
- Optimize and compress all images
- Minify CSS, JavaScript, and HTML
- Use a CDN for global content delivery
- Implement lazy loading for images
- Reduce server response time (TTFB)
Security & HTTPS
Google prioritizes secure sites. HTTPS is a confirmed ranking signal and essential for user trust, especially on pages with forms or payments.
- SSL certificate installed site-wide
- All HTTP URLs redirect to HTTPS
- HSTS header enforces secure connections
- Mixed content warnings eliminated
- Security headers properly configured
Structured data & schema markup
Schema markup is code you add to your pages that helps search engines understand your content in a structured way. It unlocks rich results — enhanced snippets with star ratings, images, FAQs, and more that dramatically increase click-through rates.
JSON-LD is Google's recommended format. It is a JavaScript notation embedded in a script tag in the page head or body. It does not change how your page looks — it only communicates with search engines.
Schema does not directly improve rankings, but rich results increase CTR by 20-30%. Higher CTR signals relevance to Google, which can indirectly boost rankings.
Organization
Tell Google about your company — name, logo, contact info, social profiles.
{"@type":"Organization","name":"SEOMate","url":"https://seo.toolly.site"} Article
Mark up blog posts and articles for enhanced search appearance.
{"@type":"Article","headline":"SEO Basics Guide","author":"SEOMate"} FAQPage
Add FAQ schema to earn expandable FAQ rich results in search.
{"@type":"FAQPage","mainEntity":[{"@type":"Question","name":"What is SEO?"}]} BreadcrumbList
Show breadcrumb trails in search results for better navigation context.
{"@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem"}]} Product
Mark up products with prices, availability, and reviews for rich snippets.
{"@type":"Product","name":"Running Shoes","offers":{"price":"99"}} HowTo
Step-by-step instructions that can appear as rich results in Google.
{"@type":"HowTo","name":"How to Write Meta Tags","step":[]} How to structure your site for SEO
A flat, logical site architecture helps crawlers find every page and distributes authority efficiently.
Technical SEO audit checklist
Run through this checklist quarterly to keep your site technically healthy and ranking well.
Crawling
- Robots.txt is valid and accessible
- XML sitemap submitted to GSC
- No important pages blocked by robots.txt
- Crawl errors resolved in GSC
Indexing
- Canonical tags on all pages
- No unintended noindex tags
- Duplicate content issues resolved
- URL parameters configured in GSC
Performance
- LCP under 2.5 seconds
- INP under 200 milliseconds
- CLS under 0.1
- TTFB under 600 milliseconds
Mobile
- Mobile-friendly test passes
- Viewport meta tag present
- No horizontal scroll on mobile
- Tap targets properly sized
Security
- HTTPS enabled site-wide
- No mixed content warnings
- SSL certificate valid
- Security headers configured
Structured Data
- JSON-LD schema on key pages
- Schema validates in Rich Results Test
- No schema warnings or errors
- Schema matches page content
Free tools for technical SEO
Implement what you have learned with these free SEOMate tools. All run in your browser, no signup required.
Schema Markup Generator
Generate valid JSON-LD structured data for your pages — no coding required.
Open ToolRobots.txt Generator
Create a properly formatted robots.txt file to control crawler access.
Open ToolSitemap Generator
Build an XML sitemap listing all your important URLs for search engines.
Open ToolRedirect Checker
Verify your redirects are working correctly and passing authority.
Open ToolCommon technical SEO issues & fixes
Most sites share the same technical problems. Here are the most frequent ones and how to fix them.
Pages not being indexed
Robots.txt blocking, noindex tags, or canonical pointing elsewhere
Check robots.txt, remove noindex, verify canonical tags, submit URL in GSC
Slow Core Web Vitals scores
Large unoptimized images, render-blocking JS, no lazy loading
Compress images to WebP, defer non-critical JS, add loading="lazy" to images
Duplicate content in index
Multiple URLs serving same content without canonical
Add rel=canonical to all duplicate pages pointing to the preferred URL
Mobile usability errors
Content wider than screen, clickable elements too close
Fix horizontal overflow, increase tap target sizes, use responsive design
Broken links and 404 errors
Deleted pages, changed URLs without redirects
Implement 301 redirects for all changed URLs, fix or remove broken internal links
Missing structured data
No schema markup on key pages
Add JSON-LD schema using our Schema Markup Generator for all page types
Technical SEO mastered? Find your keywords.
Now that your site is technically sound, learn how to find the right keywords to target and drive qualified traffic.