Technical SEO Audit Checklist for Swiss Websites
A technical SEO audit helps you identify what prevents search engines from accessing useful pages, understanding them or presenting the right version. Start with observed symptoms: missing pages, errors after a migration, differences between languages or a slow journey. The checklist below helps you organise the checks; it does not replace inspecting your own site.
1. Crawlability and Indexing
Crawlability and indexation form the cornerstone of organic search visibility. If search crawlers cannot discover or process your pages, content remains invisible. To understand Googlebot fundamentals, consult the official Google Search Central documentation on crawling and indexing.
Managing the robots.txt File
The robots.txt file governs crawler access across site directories:
Do not block CSS, JavaScript, or image resources required for page rendering.
Avoid blocking URLs containing parameters necessary for main content rendering.
Include the absolute URL of the XML sitemap using the Sitemap: directive. See robots.txt on Google Search Central.
Robots Directives and Meta Tags
Check that no unintended noindex directive blocks a page intended for organic search. You do not need to add index, follow to get the default behaviour.
Apply noindex to utility pages (shopping carts, checkout confirmations, internal search results).
Do not combine a robots.txt crawl block with a noindex page tag, as blocking crawling prevents the crawler from reading the noindex directive.
2. HTTP Responses and Redirects
Proper HTTP status code management preserves search authority and user experience. Consult the Google Search Central documentation on redirects.
Status Codes and Redirect Chains
200 OK
Ensure all canonical URLs serve a direct 200 OK status code.
301 Permanent
Use for permanent URL consolidations, directory migrations, or non-WWW to WWW redirects.
302 Temporary
Deploy for reversible language redirects or temporary tests, when the change is temporary.
Redirect Chains
Eliminate multi-step redirects (A to B to C) to link directly from A to C.
404 / 410 Errors
Ensure permanently removed pages without direct equivalents serve a clean 404 or 410 status code.
3. Canonicalization
Canonicalization specifies the preferred version of a page when duplicate content exists. For official guidance, review URL canonicalization on Google Search Central.
Implementation Standards
To indicate a preferred URL, you can use a <link rel="canonical" href="..." /> tag with the chosen absolute URL. Google treats it as a signal, not a binding instruction.
Use self-referential canonical tags on original content pages.
Ensure canonical target URLs return a 200 HTTP status code and are not blocked by noindex or robots.txt.
For parameters and filters, first decide which pages are equivalent and which meet distinct needs. Select a preferred URL for real duplicates; do not canonicalise every filtered page to one destination.
4. XML Sitemaps
XML sitemaps streamline URL discovery for crawlers. Review technical rules in the Google Search Central overview of sitemaps.
Technical Requirements
Encode all XML sitemap files in UTF-8 format.
Adhere to limits of 50,000 URLs and 50 MB uncompressed per sitemap file. Use a sitemap index file for larger sets.
Include only indexable, canonical 200 OK URLs (exclude redirects and 404 errors).
Update the <lastmod> attribute only when meaningful content revisions occur.
5. JavaScript Rendering
Client-side JavaScript frameworks require specific steps to support content discovery. Consult the guide on JavaScript SEO basics on Google Search Central.
Indexing Dynamic Applications
Use standard HTML <a href="..."> links so crawlers can discover URLs without JavaScript execution.
Consider Server-Side Rendering (SSR) or Static Site Generation (SSG) if client-side rendering prevents content discovery or complicates maintenance. Google can render JavaScript; check the result rather than assuming a framework guarantees indexing.
Compare initial and rendered HTML: check that search engines can read the useful content and metadata.
Audit final rendered HTML using the URL Inspection tool in Google Search Console.
6. Mobile Usability and Core Web Vitals
Google evaluates page experience using real-world field data (CrUX). Consult official guides on Core Web Vitals on Google Search Central and the announcement introducing INP to Core Web Vitals.
Official Core Web Vitals Thresholds (75th Percentile)
Largest Contentful Paint (LCP)
≤ 2.5 seconds. Measures rendering speed of the largest visible element.
Interaction to Next Paint (INP)
≤ 200 milliseconds. Assesses webpage responsiveness to user interactions. INP replaced FID on March 12, 2024.
Cumulative Layout Shift (CLS)
≤ 0.1. Measures visual stability during page load.
These metrics measure user experience quality. Meeting these thresholds does not guarantee search rankings or fixed conversion increases. Missing these thresholds does not trigger an automatic algorithmic penalty.
Mobile Usability
Deploy a responsive design that adapts smoothly across mobile screen viewports.
Check control sizes and spacing against your chosen accessibility standard. WCAG 2.2 AA specifies 24 × 24 CSS pixels for targets, with exceptions relating to spacing and inline links, among others.
Ensure text is immediately readable without requiring horizontal scrolling or manual zooming.
7. Multilingual Routing (FR/EN/DE/IT)
Multilingual sites must route users cleanly to their preferred language version. Review guidelines on managing multilingual sites on Google Search Central.
Hreflang Configuration
Define language and region targets using ISO codes (e.g., fr-CH, de-CH, it-CH, en).
Enforce strict reciprocity: linking the FR page to the DE page via hreflang="de-CH" requires a return link from DE to FR via hreflang="fr-CH".
You can add hreflang="x-default" for a suitable fallback page; its absence is not always an error.
Organize URLs within clear subdirectories (/fr/, /de/, /it/, /en/).
8. Prioritization Matrix and Decision Aid
A proposed priority order to adapt
P1 Priority (Critical)
Crawl blocks in robots.txt, unintended noindex tags, redirect loops, or JavaScript rendering failures.
P2 Priority (High)
Canonical tag conflicts, missing reciprocal hreflang links, sitemap XML syntax errors, LCP > 4.0s.
P3 Priority (Medium)
Multi-step 301 redirect chains, minor layout shifts and usability adjustments, according to their actual effect.
Fictional Audit Example
A Swiss e-commerce site observes an indexation drop in its /en/ directory. An audit reveals that /en/ pages contain canonical tags pointing incorrectly to /fr/, while /fr/ lacks an hreflang="en" tag. The fix requires restoring self-referential canonical tags on /en/ and re-establishing reciprocal hreflang links.
Organise fixes and check their effect
Assign an owner to each issue, with affected URLs and a way to reproduce it. Test a fix on a representative sample before applying it across the site. After publication, check the HTTP response, rendered content and URL Inspection. An indexing request does not guarantee inclusion.
For your 2027 plan, include these checks in launches and migrations rather than planning an annual rebuild without a diagnosis. Our hreflang and canonical guide explains language relationships. Our accessibility guide helps you choose an appropriate standard.