Technical SEO is the foundation that all other search engine work rests on. Without a solid technical base, even the best content and strongest backlinks will underperform. This checklist covers every critical technical aspect you should audit and optimize — with concrete action items you can implement immediately. This complements our complete SEO guide for 2026. See also our guides on Core Web Vitals, internal linking strategy, schema markup, canonical URLs, and JavaScript SEO.
Crawlability: Make sure search engines can find your content
Crawlability is about ensuring search engine bots can discover and read your pages. According to Google's own guidelines (Google Search Central, 2025), this is the first step in the indexing process — if Googlebot cannot crawl a page, it simply does not exist in search results.
Start with your robots.txt file. It controls which parts of your site are accessible to crawlers. A common mistake is blocking important resources like CSS and JavaScript files, which prevents Google from rendering pages correctly. Use Google Search Console's robots.txt tester to verify the file works as intended.
Crawl budget is especially important for larger sites. Google allocates a limited amount of crawl resources to each site. Ensure the budget is spent on pages that actually provide value, not on filter parameters, sorting variants, or outdated pages.
- Verify that robots.txt does not block important pages, CSS, or JavaScript
- Submit an updated XML sitemap via Google Search Console
- Limit crawling of low-value pages with robots.txt or meta robots
- Implement pagination with rel="next" and rel="prev" where relevant
- Avoid infinite crawl loops from calendars, filters, or search functions
- Check crawl statistics in Google Search Console under Settings > Crawling
Indexation: Control what appears in search results
Indexation is the process where Google stores and organizes content from crawled pages. The goal is to have all valuable pages indexed while keeping duplicates and low-quality pages out. Google reports indexation status in Search Console under "Pages" — this should be checked monthly.
Canonical tags are your most important tool for handling duplicate content. Every page should have a self-referencing canonical tag pointing to its own URL. For pages that exist in multiple versions (with and without parameters, HTTP/HTTPS, www/non-www), the canonical should point to the preferred version.
Index bloat — where Google indexes far more pages than you have real content — is a widespread problem. Check by searching "site:yourdomain.com" and compare the count with how many pages you actually want indexed. Use noindex directives for pages without search value, such as internal search results, thin tag pages, and outdated campaign pages.
- Implement self-referencing canonical tags on all pages
- Use noindex on pages without search value (tag pages, internal search results, thin pages)
- Identify and fix orphan pages — pages with no internal links pointing to them
- Check the "Pages" report in Google Search Console monthly for indexation issues
- Remove outdated pages from the index with 410 status codes or noindex
- Verify that important pages are actually indexed using the "URL Inspection" tool
Site architecture: Build a logical, crawl-friendly structure
Good site architecture makes it easy for both users and search engines to find content. The main rule is that no important page should be more than three clicks from the homepage. A flat architecture with clear hierarchy provides better crawling and distribution of link equity.
URL structure should be readable, consistent, and hierarchical. Use directories that reflect the content's organization: /services/seo/, /blog/technical-seo-checklist/. Avoid unnecessary parameters, session IDs, and dynamic strings in URLs that should be indexed.
Internal linking is one of the most underrated SEO tools. Every article should link to relevant service pages and related content. At LeapJet, we use topic clusters where a pillar page links to and from all supporting articles — this strengthens topical authority and helps Google understand the relationships between your pages.
- Keep important pages within 3 clicks from the homepage
- Use descriptive, hierarchical URLs without unnecessary parameters
- Implement breadcrumbs with BreadcrumbList schema markup
- Build an internal linking strategy with topic clusters and contextual linking
- Handle faceted navigation with canonical tags or robots directives
- Create and maintain an HTML sitemap for large sites
Core Web Vitals and page speed
Core Web Vitals are Google's standardized measures of user experience, and they are a confirmed ranking factor. The three metrics are: Largest Contentful Paint (LCP) — should be under 2.5 seconds, Interaction to Next Paint (INP) — should be under 200 milliseconds, and Cumulative Layout Shift (CLS) — should be under 0.1.
LCP is improved by optimizing the largest visible element in the viewport. For most pages, this is a hero image or large text block. Use modern image formats (WebP/AVIF), implement lazy loading for below-the-fold images, and preload the critical hero image. Server-side rendering or static generation provides significantly better LCP than pure client-side rendering.
INP measures responsiveness during user interactions and replaced FID in March 2024. Optimize by breaking up long JavaScript tasks, using requestIdleCallback for non-critical code, and minimizing work in event handlers. CLS is improved by always specifying dimensions on images and videos, reserving space for ads and dynamic content, and avoiding DOM changes that push visible content.
- LCP < 2.5s: Preload hero images, use WebP/AVIF, optimize server response time
- INP < 200ms: Break up long JS tasks, minimize main thread work
- CLS < 0.1: Set dimensions on all media elements, reserve space for dynamic content
- Use PageSpeed Insights and CrUX data to measure real-world performance
- Implement caching with effective Cache-Control headers
- Minimize render-blocking CSS and JavaScript
Mobile optimization and mobile-first indexing
Google uses mobile-first indexing by default, meaning it is the mobile version of your site that gets crawled and indexed. According to Google (Search Central, 2025), the mobile version should contain all the content you want indexed — content that only appears on desktop will be ignored.
Responsive design is the recommended approach. Ensure all elements are usable on mobile devices: touch targets should be at least 48x48 pixels with sufficient spacing, text should be readable without zooming (minimum 16px font size), and horizontal scrolling should never occur.
Test mobile performance with Google's Mobile-Friendly Test and Lighthouse. Pay particular attention to pop-ups and interstitials that cover content on mobile — Google actively penalizes this. Use inline banners or slide-ins that do not block the user experience instead.
- Verify that all content is accessible on the mobile version
- Touch targets minimum 48x48px with 8px spacing between clickable elements
- Avoid intrusive interstitials and pop-ups on mobile
- Test with Google's Mobile-Friendly Test and Lighthouse mobile mode
- Ensure the viewport meta tag is correctly configured
- Optimize images for mobile networks with responsive images (srcset)
Structured data and Schema.org
Structured data helps search engines understand your content better and can generate rich results (rich snippets) in search results. According to a study by Milestone Research (2025), pages with structured data receive an average of 40% higher click-through rate than pages without.
Start with the most valuable schema types: Organization (for business information), LocalBusiness (for local businesses), Article and BlogPosting (for content), FAQPage (for Q&A sections), BreadcrumbList (for breadcrumbs), and Product/Service (for services and products).
Use JSON-LD format for implementation — this is Google's preferred method. Always test with Google's Rich Results Test and Schema Markup Validator. Remember that structured data must reflect the content actually displayed on the page — misleading markup can result in a manual penalty.
- Implement Organization/LocalBusiness schema with logo, contact info, and sameAs links
- Use Article/BlogPosting schema with author, datePublished, and dateModified
- Add FAQPage schema on pages with question-and-answer content
- Implement BreadcrumbList schema matching the visible breadcrumbs
- Test with Google's Rich Results Test and Schema Markup Validator
- Monitor rich results in Google Search Console under "Enhancements"
Security: HTTPS, mixed content, and security headers
HTTPS is a confirmed ranking factor and a prerequisite for many modern web features. All pages should be served over HTTPS with a valid SSL certificate. Mixed content — where HTTPS pages load resources over HTTP — should be eliminated completely, as it both breaks security and can prevent resources from loading in modern browsers.
Security headers provide an additional layer of protection and signal to search engines that the site is well maintained. The most important are: Strict-Transport-Security (HSTS) to enforce HTTPS, Content-Security-Policy (CSP) to prevent XSS attacks, X-Content-Type-Options to prevent MIME sniffing, and Permissions-Policy to control API access.
Good security implementation also indirectly benefits SEO through higher user trust, lower bounce rates, and better conversion rates. Use SecurityHeaders.com or Mozilla Observatory to check your implementation.
- Verify all pages are accessible over HTTPS with a valid certificate
- Eliminate all mixed content (HTTP resources on HTTPS pages)
- Implement HSTS with minimum 1-year max-age
- Set up Content-Security-Policy, X-Content-Type-Options, and X-Frame-Options
- Redirect all HTTP traffic permanently (301) to HTTPS
- Check security headers with SecurityHeaders.com or Mozilla Observatory
International SEO: hreflang and language targeting
For multilingual websites, correct hreflang implementation is critical for showing the right language version to the right user. Hreflang tags tell search engines which language and regional variants exist for a page, preventing them from being treated as duplicate content.
Implement hreflang as link elements in the head section, in HTTP headers, or in the XML sitemap. Every set of hreflang tags must be complete and reciprocal — if page A points to page B, page B must also point back to page A. A common error is forgetting the x-default tag, which specifies the default version for users outside the specified regions.
For Norwegian businesses targeting both Norwegian and English audiences, we recommend using no and en as language codes. If you also distinguish between Norwegian Bokmal and Nynorsk, use nb and nn. Verify your implementation with the hreflang report in Google Search Console or third-party tools like Ahrefs.
- Implement hreflang tags for all language versions of each page
- Include x-default for the default version
- Ensure hreflang references are reciprocal (bidirectional)
- Use correct ISO 639-1 language codes and ISO 3166-1 Alpha-2 country codes
- Verify with Google Search Console's hreflang report
- Avoid automatic redirection based on IP — let users choose their language
JavaScript SEO: Rendering and hydration
Modern websites often use JavaScript frameworks like React, Next.js, or Vue. Google can render JavaScript, but it happens in a separate phase (Web Rendering Service) that can take days or weeks — meaning JS-dependent content is indexed more slowly. According to Google (Martin Splitt, Google I/O 2025), server-side rendering (SSR) remains the safest approach for SEO-critical content.
If you use client-side rendering, verify that content actually renders correctly for Googlebot using the URL Inspection tool in Search Console. Check the rendered HTML, not just the source code. Common issues include content behind lazy loading that never triggers, API calls blocked by robots.txt, and JavaScript errors that prevent rendering.
Dynamic rendering — where you serve a pre-rendered version to crawlers — is a valid solution for sites that cannot migrate to SSR. Google recommends this as a temporary solution. For new projects, at LeapJet we always recommend Next.js with SSR or static generation, which provides the best of both worlds.
- Use server-side rendering (SSR) or static generation for SEO-critical content
- Test rendering with the URL Inspection tool in Google Search Console
- Avoid making important content dependent on user interaction to render
- Ensure internal links are crawlable HTML links, not JavaScript events
- Use dynamic rendering as a temporary solution if SSR is not possible
- Monitor JavaScript errors in Search Console under "Crawling"
Technical SEO audit: Workflow and prioritization
A systematic technical SEO audit should be conducted quarterly for most sites, and monthly for large or frequently updated sites. At LeapJet, we use a prioritization matrix that weighs each issue based on impact (high/medium/low) and effort (easy/medium/complex). Always fix high-impact/easy-effort issues first.
The most important tools for a technical SEO audit are: Google Search Console (free, first-party data), Screaming Frog SEO Spider (crawling and analysis), Ahrefs or Semrush (backlinks and competitive analysis), PageSpeed Insights (performance), and Chrome DevTools (debugging). For large sites, Lumar (formerly DeepCrawl) or Sitebulb are good alternatives to Screaming Frog.
Document all findings in a structured report with a prioritized action plan. Include current status, recommended action, expected impact, and responsible person. Follow up with a new crawl after implementation to verify that changes have the desired effect.
- Conduct a full technical audit quarterly, critical checks monthly
- Use a prioritization matrix: impact x effort to rank actions
- Run a crawl with Screaming Frog or similar tool as a baseline
- Check Google Search Console weekly for new crawl errors and indexation issues
- Document findings and actions in a structured report with owner and deadline
- Verify implementation with a new crawl and compare against baseline
Sources and further reading
This article draws on official documentation and recognized industry sources:
- Google Search Central — Technical SEO and Crawling Guidelines (2025)
- Google Developers — Core Web Vitals and Page Speed (2025)
- Google Search Central — Mobile-first Indexing Best Practices (2025)
- Google Search Central — Hreflang Implementation (2025)
- Google Search Central — JavaScript SEO Best Practices (2025)
- Milestone Research — Structured Data and Rich Results CTR Study (2025)
- web.dev — Core Web Vitals Optimization Guides (2025)
