Priority Key:
Critical
High
Medium
130+ items · 10 categories · Updated for 2025Quick Reference
Core Web Vitals Targets 2025
These are Google's official thresholds for Core Web Vitals. Aim for Good across all metrics — particularly on mobile where most users now browse.
Essential Tools
Technical SEO Tools You Need
Use these tools to audit your site against this checklist. Most have a free tier that is sufficient for initial audits.
🕷️
01Category
Crawlability & Indexing
If Google cannot crawl and index your pages, nothing else matters. These are the foundational controls that determine whether your content appears in search results at all.
15Items
robots.txt file exists at /robots.txt and is correctly configured — verify at yourdomain.com/robots.txtCritical
robots.txt does not accidentally block important pages, assets, or the entire site with 'Disallow: /'Critical
XML sitemap exists and lists all important canonical URLs — submitted to Google Search ConsoleCritical
XML sitemap is accessible at /sitemap.xml and linked from robots.txtCritical
No important pages have a noindex meta tag or X-Robots-Tag: noindex HTTP header accidentally appliedCritical
Google Search Console verified and connected — shows no critical indexing errorsCritical
All important pages are indexed — verify with site:yourdomain.com in Google SearchCritical
Sitemap includes only canonical URLs — no redirected URLs, pagination variants, or noindex pagesHigh
Sitemap updated automatically when new pages are published (dynamic sitemap generation)High
Crawl budget not wasted on duplicate content, infinite scroll, session ID URLs, or low-value pagesHigh
Internal search result pages blocked from indexing via noindex or robots.txtHigh
Pagination handled correctly — use rel=next/prev or canonical tags, not blocking paginated pagesHigh
Log file analysis done to understand which pages Googlebot crawls and how oftenMedium
Orphan pages identified — important pages with no internal links pointing to themMedium
Crawl depth reviewed — important pages reachable within 3 clicks from the homepageMedium
7 critical · 5 high · 3 medium
📄
02Category
On-Page Technical Elements
Meta tags, heading structure, and canonical tags are the basic technical signals Google uses to understand your pages. Missing or duplicated elements cause ranking confusion.
15Items
Every page has a unique, descriptive title tag — 50 to 60 characters, contains primary keywordCritical
Every page has a unique meta description — 120 to 160 characters, compelling and click-worthyCritical
Every page has exactly one H1 tag — contains the primary keyword and matches the page topicCritical
Canonical tags on every page pointing to the preferred URL — prevents duplicate content penaltiesCritical
Self-referencing canonical tags on all pages — even if there is no duplicate, canonical must be presentCritical
No two pages have identical or near-identical title tags — triggers keyword cannibalisationCritical
H2 and H3 heading hierarchy is logical and used for structure — not styled via CSS font-size on div elementsHigh
URL structure is clean, lowercase, uses hyphens not underscores, contains target keywordHigh
URLs do not contain session IDs, tracking parameters, or unnecessary query stringsHigh
Open Graph tags (og:title, og:description, og:image) on all pages for social sharingHigh
Twitter Card meta tags configured — at minimum twitter:card, twitter:title, twitter:descriptionHigh
Favicon present and correctly sized (32×32 and 180×180 for Apple)High
Meta robots tag explicitly set on all pages (index, follow for public pages)Medium
Hreflang tags implemented for all multilingual or multi-regional versions of pagesMedium
Lang attribute set correctly on the HTML element for the primary language of each pageMedium
6 critical · 6 high · 3 medium
⚡
03Category
Core Web Vitals & Performance
Core Web Vitals are Google's user experience metrics and a confirmed ranking signal. A Good rating across LCP, INP, and CLS is the target for competitive search rankings in 2025.
16Items
Largest Contentful Paint (LCP) under 2.5 seconds on mobile — verified in Google Search Console field dataCritical
Interaction to Next Paint (INP) under 200ms — key interactive elements respond immediatelyCritical
Cumulative Layout Shift (CLS) score under 0.1 — no unexpected content movement during page loadCritical
All images have explicit width and height attributes — prevents layout shift during loadCritical
Largest Contentful Paint element identified and loading optimised (preload, priority attribute on hero image)Critical
No render-blocking JavaScript or CSS in the critical path — defer or async non-critical scriptsCritical
Images served in WebP or AVIF format — 30–50% smaller than JPEG/PNG with equal qualityHigh
Images lazy-loaded below the fold — loading='lazy' on all non-hero imagesHigh
Fonts loaded efficiently — font-display: swap to prevent invisible text during font loadHigh
Critical CSS inlined in the head — prevents render-blocking stylesheet requestsHigh
JavaScript bundle size minimised — code splitting, tree shaking, and removing unused dependenciesHigh
Third-party scripts (analytics, chat widgets, ads) deferred until after main content loadsHigh
Content Delivery Network (CDN) configured — static assets served from edge nodes close to the userHigh
Lighthouse performance score above 85 on both mobile and desktop — verified monthlyMedium
Time to First Byte (TTFB) under 800ms — server response time optimised via caching or edge functionsMedium
Preconnect hints added for critical third-party origins (fonts.googleapis.com, analytics providers)Medium
6 critical · 7 high · 3 medium
🏷️
04Category
Structured Data & Schema Markup
Structured data tells Google what your content means, enabling rich results in search. Rich results have higher click-through rates and improve AEO — making your content readable by AI systems.
15Items
JSON-LD structured data implemented — not Microdata or RDFa (Google recommends JSON-LD)Critical
Organization schema on the homepage — includes name, URL, logo, contact, and social profilesCritical
WebPage or Article schema on all content pages — includes headline, description, author, datePublishedCritical
BreadcrumbList schema on all interior pages — enables breadcrumb rich results in GoogleCritical
FAQPage schema on all pages with FAQ sections — enables FAQ accordion rich resultsCritical
Structured data validated with Google's Rich Results Test — no errors, only warningsCritical
Product schema on all product pages — includes name, description, image, price, availability, and reviewsHigh
Review and AggregateRating schema where applicable — shows star ratings in search resultsHigh
LocalBusiness schema if business has a physical location — enables Google Maps integrationHigh
HowTo schema for step-by-step guide pages — can appear as rich results with stepsHigh
Structured data matches visible on-page content — Google penalises schema that contradicts page contentHigh
No conflicting duplicate schema types on the same pageHigh
SiteLinksSearchBox schema if site has internal search functionalityMedium
Event schema for any event pages with date, location, and ticket informationMedium
Schema markup monitored in Search Console Enhancement reports — fix any warnings or errorsMedium
6 critical · 6 high · 3 medium
📱
05Category
Mobile Optimisation
Google uses mobile-first indexing — the mobile version of your site is the primary version Google crawls and ranks. A site that is poor on mobile will not rank well, regardless of desktop quality.
13Items
Viewport meta tag present on every page: <meta name='viewport' content='width=device-width, initial-scale=1'>Critical
Site renders correctly on screens from 375px width (iPhone SE) upwardsCritical
No horizontal scrolling on mobile — all content fits within viewport widthCritical
Touch targets (buttons, links) are minimum 44×44 pixels and have adequate spacing between themCritical
Text readable without zooming — minimum 16px base font size on mobileCritical
Google Mobile-Friendly Test passes — test at search.google.com/test/mobile-friendlyCritical
Mobile navigation is usable — hamburger menu or alternative navigation works correctlyHigh
Images and media scale correctly on mobile — no overflow or distortionHigh
Forms usable on mobile — inputs large enough to tap, keyboard type appropriate (email, number, tel)High
No interstitials or popups that block mobile content — Google penalises intrusive interstitials on mobileHigh
Mobile page speed meets Core Web Vitals thresholds — mobile is typically 2–3× slower than desktopHigh
Accelerated Mobile Pages (AMP) considered for news or article content if high mobile trafficMedium
Mobile user experience tested with real devices, not just Chrome DevTools emulationMedium
6 critical · 5 high · 2 medium
🔒
06Category
Security & HTTPS
HTTPS is a confirmed Google ranking signal. Mixed content and invalid SSL certificates are not just security issues — they are SEO issues that depress rankings and trigger browser warnings.
12Items
HTTPS enabled on all pages — SSL certificate valid and not expiredCritical
All HTTP URLs redirect to HTTPS via 301 permanent redirectCritical
No mixed content warnings — all resources (images, scripts, fonts) loaded over HTTPSCritical
SSL certificate covers all subdomains in use (www, blog, app, api)Critical
HTTP Strict Transport Security (HSTS) header configured — forces HTTPS on repeat visitsCritical
Security headers configured: Content-Security-Policy, X-Frame-Options, X-Content-Type-OptionsHigh
No sensitive information exposed in page source, URLs, or browser storageHigh
SSL certificate auto-renews — set up Let's Encrypt or managed certificate renewal alertHigh
Referrer-Policy header set to control which referrer information is shared with other sitesHigh
Permissions-Policy header configured to disable unused browser featuresMedium
Cross-Origin Resource Policy headers configured for assets served from CDNMedium
SSL Labs grade A or A+ at ssllabs.com/ssltest — verify TLS configuration is currentMedium
5 critical · 4 high · 3 medium
🔗
07Category
URLs, Redirects & Canonicalisation
URL structure and redirect management determine how link equity flows through your site. Redirect chains, loops, and duplicate URLs dilute ranking signals and waste crawl budget.
13Items
www and non-www versions of the site redirect to a single canonical version via 301Critical
Trailing slash URLs consistent — either /page or /page/, not both, with one redirecting to the otherCritical
No redirect chains — every redirect goes directly from source to final destination (max 1 hop)Critical
No redirect loops — A redirects to B which redirects back to ACritical
All 404 pages have a proper 404 HTTP status code — soft 404s (200 status on error page) fixedCritical
All internal links point to the canonical URL — not to redirect URLs or www/non-www variantsCritical
Custom 404 page provides helpful navigation and does not feel like a dead endHigh
Old URLs that receive external links redirect 301 to the most relevant current pageHigh
URL parameters tracked in Google Search Console — faceted navigation, session IDs, tracking parameters handledHigh
No duplicate content from capitalisation differences — /About and /about both resolve to the same canonicalHigh
Redirect map maintained — document all redirects with source, destination, and reasonMedium
410 Gone status used for permanently deleted content with no replacement — not 404Medium
URL structure reviewed for keyword inclusion — descriptive slugs rank better than numeric IDsMedium
6 critical · 4 high · 3 medium
🕸️
08Category
Internal Linking & Site Architecture
Internal links distribute link equity across your site and signal to Google which pages are most important. A well-structured site architecture is a significant competitive SEO advantage.
12Items
All important pages reachable within 3 clicks from the homepageCritical
No broken internal links — verified with Screaming Frog or Google Search ConsoleCritical
Navigation links use descriptive anchor text — not 'click here' or 'read more'Critical
Most important pages receive the most internal links — prioritise cornerstone contentHigh
Internal links use keyword-rich anchor text relevant to the destination page topicHigh
Topic cluster structure implemented — pillar pages link to cluster content, cluster content links back to pillarHigh
Breadcrumb navigation present on all interior pages — improves crawlability and user orientationHigh
Related content links at the bottom of blog posts and resource pages — increases pages per sessionHigh
Footer links limited to most important pages — avoid link dilution with excessive footer navigationHigh
Silo structure maintained — topic-related pages link to each other, not across unrelated topicsMedium
Orphan pages identified and linked from relevant pages — no important page has zero internal linksMedium
Link equity flow reviewed — identify pages accumulating links that are not strategic targetsMedium
3 critical · 6 high · 3 medium
🌍
09Category
International & Local SEO
If your site targets multiple countries or languages, hreflang implementation is critical. Incorrect hreflang causes search engines to serve the wrong language version to international users.
11Items
Hreflang tags implemented for all language and regional variants — in both HTTP headers and HTMLCritical
Each hreflang tag links to its own canonical URL — and that URL's hreflang points back (reciprocal)Critical
x-default hreflang tag present — specifies the fallback page for users with no matching localeCritical
Hreflang uses correct language-country codes (en-US, en-GB, fr-FR) not just language (en, fr)Critical
Separate URLs for each language/region — not just automatic translation on the same URLHigh
Translated pages are professionally translated — not machine-translated thin contentHigh
Geotargeting configured in Google Search Console for country-specific contentHigh
Local business NAP (Name, Address, Phone) consistent across all pages and directoriesHigh
Country-specific top-level domains (.co.uk, .de) or subdirectories (/en/, /de/) used for regional targetingMedium
Currency, date format, and units of measurement localised for each regional versionMedium
Hreflang validated with dedicated tool (hreflang.org checker or Screaming Frog)Medium
4 critical · 4 high · 3 medium
📊
10Category
Monitoring & Ongoing Maintenance
Technical SEO is not a one-time task. Rankings can drop overnight when pages lose their index status, develop speed issues, or accumulate crawl errors. These monitoring practices protect your hard-won rankings.
13Items
Google Search Console checked weekly — address any new crawl errors, manual actions, or coverage issuesCritical
Core Web Vitals report in Search Console reviewed monthly — address any URLs moving to Needs ImprovementCritical
Alerts configured for significant drops in organic traffic or keyword ranking changesCritical
Full site crawl run monthly with Screaming Frog or Ahrefs — catch new broken links or missing tagsHigh
SSL certificate expiry monitored with automated alert at 30 days before expiryHigh
Uptime monitoring in place — Google cannot crawl pages that are downHigh
Page speed scores tracked over time — deploy alerts if Lighthouse score drops below 80High
Backlink profile monitored — disavow toxic links that could trigger Google manual actionsHigh
Google algorithm update impact tracked — correlate traffic changes with known update datesHigh
Keyword ranking tracking for all target keywords — weekly snapshots to identify movementMedium
Competitor technical SEO audited quarterly — identify gaps and opportunities they have that you do notMedium
Annual full technical SEO audit conducted — comprehensive review of all items in this checklistMedium
New content pages reviewed for technical compliance before publishing — do not launch pages with missing tagsMedium
3 critical · 6 high · 4 medium
Built by 4Byte
How 4Byte builds SEO-ready websites
Every website and SaaS product we build passes this checklist before launch. Technical SEO is baked into our development process — not added as an afterthought.
We build on Next.js which gives us server-side rendering, automatic image optimisation, built-in Core Web Vitals performance, and full control over every meta tag and structured data element — making technical SEO excellence the default, not the exception.
Lighthouse scores above 90 on all production builds
Structured data (JSON-LD) on every page type from day one
Dynamic sitemaps and robots.txt generated automatically
Core Web Vitals optimised during development — not post-launch
45+
SEO-Ready Sites Built
All pass this checklist
95+
Avg Lighthouse Score
Performance + SEO + A11y
< 2s
Avg LCP on Builds
Well within Good threshold
≤ 4hrs
Response Time
On all new enquiries
FAQ