Technical SEO: the developer checklist for SEO consultants the developer checklist
You are an SEO consultant and you spend time chasing technical fixes your developer has not made yet? This 5-part checklist gives you a shared language to frame audits, prioritize actions and deliver sites that actually rank.
You have delivered a complete technical SEO audit. Your 30 recommendations are documented, prioritized, argued. Three months later, your client asks why traffic has not moved. You look at the site: 5 points have been fixed. The other 25 are still waiting for the developer.
Every SEO consultant knows this situation. It is not caused by the developer's lack of goodwill: it is the symptom of a shared language problem between two disciplines that do not naturally communicate. This 5-part technical SEO checklist was designed to bridge that gap. Share it directly with your developer or technical partner at the start of each project: it translates your requirements into precise, verifiable tasks, sorted by priority.
The gap between SEO and development
The SEO consultant thinks in terms of signals, authority, crawl budget and SERPs. The developer thinks in terms of components, deployments, application performance and technical debt. These two perspectives are not incompatible, but they do not speak naturally to each other.
The concrete problem
A developer who does not understand why canonical tags matter will implement them at the last minute, partially, or not at all. An SEO consultant who does not understand server-side rendering constraints will recommend things that are technically impossible in the chosen architecture. The result: lost recommendations, wasted time, and a client who does not see the expected results.
The good news: you do not need your developer to become an SEO consultant, or vice versa. You need a clear collaboration agreement, in the form of a checklist, that defines what must be delivered and how to verify it.
According to an Ahrefs study covering over a billion web pages, 90.63% of pages receive no organic traffic from Google. Among the main causes are technical issues that prevent correct indexation. Solid foundations alone are not enough to rank, but they are the prerequisite without which nothing else can work.
Part 1: Technical foundations
Technical foundations determine whether Google can access your site, understand it, and index it correctly. Without them, everything else is pointless.
Robots.txt
The robots.txt file tells crawling robots what they can and cannot visit. A bad configuration can block entire sections of your site from indexation without you noticing.
| Checkpoint | Verification tool |
|---|---|
| The robots.txt file exists at the site root | Direct access: domain.com/robots.txt |
| Important pages are not blocked by Disallow | Google Search Console - URL Inspection |
| The sitemap URL is referenced in robots.txt | Direct file review |
| CSS and JS resources are not blocked | GSC - Coverage report |
| Critical URL parameters are not blocked | Screaming Frog |
XML Sitemap
A well-built sitemap helps Google discover and prioritize your pages. Its absence or poor configuration slows indexation, especially for new sites.
| Checkpoint | Verification tool |
|---|---|
| The sitemap exists and is accessible (/sitemap.xml) | Direct access + GSC - Sitemaps |
| It has been submitted in Google Search Console | GSC - Sitemaps |
| It contains only indexable pages (no noindex pages) | Screaming Frog |
| All URLs are canonical (HTTPS, consistent www) | Screaming Frog |
| It updates automatically when new pages are added | Test after adding a page |
| Important images are listed in the image sitemap | Screaming Frog |
Redirects
Poorly configured redirects dilute link authority and create chains that slow crawling. A single misconfiguration at the domain level can cost months of positioning.
| Checkpoint | Verification tool |
|---|---|
| All HTTP to HTTPS redirects are 301s | httpstatus.io |
| www to non-www redirects (or vice versa) are 301s | httpstatus.io |
| No redirect chains exist (A to B to C) | Screaming Frog |
| Deleted pages redirect to a relevant page, not the homepage | Screaming Frog |
| 404 errors have been identified and addressed | GSC - Coverage |
| Temporary 302 redirects are not used incorrectly | Screaming Frog |
Part 2: Performance and Core Web Vitals
Since Google's Page Experience Update in 2021, Core Web Vitals have been an official ranking factor. LCP, INP and CLS measure real user experience and directly impact your search ranking. We have a dedicated article on Core Web Vitals for agencies in 2026 if you want to go deeper on each metric.
Official Google thresholds in 2026
LCP (Largest Contentful Paint): under 2.5 seconds = Good, between 2.5 and 4 seconds = Needs Improvement, over 4 seconds = Poor. INP (Interaction to Next Paint): under 200 ms = Good, between 200 and 500 ms = Needs Improvement, over 500 ms = Poor. CLS (Cumulative Layout Shift): under 0.1 = Good, between 0.1 and 0.25 = Needs Improvement, over 0.25 = Poor.
LCP (Largest Contentful Paint): main loading time
| Checkpoint | Verification tool |
|---|---|
| The hero image is preloaded with the preload attribute | PageSpeed Insights - Opportunities |
| The LCP image is in WebP or AVIF format | Lighthouse - Images |
| Server responds in under 200 ms (TTFB) | PageSpeed Insights - TTFB |
| Fonts are preloaded and do not use font-display:block | Lighthouse |
| A CDN distributes static assets | WebPageTest |
| The LCP element does not depend on a client-side script to render | Lighthouse - LCP element |
INP (Interaction to Next Paint): responsiveness
| Checkpoint | Verification tool |
|---|---|
| Third-party scripts (analytics, chat, ads) are loaded asynchronously | Lighthouse - Third-party code |
| No Long Tasks over 50 ms block the main thread | Chrome DevTools - Performance |
| Event handlers (click, scroll) are optimized | Chrome DevTools |
| JavaScript bundle is split (code splitting) to avoid a heavy initial load | Lighthouse - JavaScript execution |
CLS (Cumulative Layout Shift): visual stability
| Checkpoint | Verification tool |
|---|---|
| All images have explicit width and height attributes defined | Screaming Frog |
| Ad blocks and embeds have placeholder containers | Visual test |
| Web fonts do not cause visible FOUT during loading | Visual test |
| CSS animations do not affect layout (transform rather than width/height) | Lighthouse |
Image optimization
| Checkpoint | Verification tool |
|---|---|
| All images are compressed before upload | Squoosh or ImageOptim |
| Lazy loading is enabled for below-fold images | Chrome Inspector |
| Responsive images use the srcset attribute | Screaming Frog |
| No critical background image is loaded through CSS alone | Lighthouse - LCP element |
Part 3: HTML structure and markup
The HTML structure of your pages determines how Google understands your content and how it extracts relevant information for search results. These elements are often overlooked during development because they are not visible, but they are among the most impactful for SEO.
Title tags and meta descriptions
| Checkpoint | Verification tool |
|---|---|
| Each page has a unique title tag | Screaming Frog |
| Titles are between 50 and 60 characters | Screaming Frog |
| Each page has a unique meta description | Screaming Frog |
| Meta descriptions are between 120 and 155 characters | Screaming Frog |
| No page has duplicate title or meta description | Screaming Frog - Duplicates |
| Titles naturally include the target keyword | Manual review |
Heading structure
| Checkpoint | Verification tool |
|---|---|
| Each page has exactly one H1 | Chrome Inspector |
| The H1, H2, H3 hierarchy is respected without skips | Screaming Frog |
| Headings naturally contain target keywords | Manual review |
| The H1 differs from the title but remains consistent | Manual review |
Canonical tags
| Checkpoint | Verification tool |
|---|---|
| Each page has a canonical tag pointing to itself | Chrome Inspector |
| Canonicals use absolute URLs (not relative) | Screaming Frog |
| Paginated pages handle their canonicals correctly | Screaming Frog |
| The canonical is consistent with the sitemap URL | Screaming Frog |
Open Graph and social meta tags
| Checkpoint | Verification tool |
|---|---|
| og:title, og:description and og:image tags are present | Facebook Debugger |
| The og:image is at least 1200 x 630 px | Facebook Debugger |
| Twitter Card tags are configured | Twitter Card Validator |
| Social images are hosted on the same domain | Chrome Inspector |
Part 4: Indexation and duplicate content
Duplicate content and indexation issues are among the most frequent causes of SEO underperformance. They are also among the simplest to fix if identified early, and among the most costly to ignore over the long term.
Indexation control
| Checkpoint | Verification tool |
|---|---|
| Pages not meant to be indexed carry the meta robots noindex tag | Screaming Frog |
| Noindex pages are not in the XML sitemap | Screaming Frog |
| URL parameters (filters, sorting, sessions) are handled with canonical or noindex | GSC - URL Inspection |
| Internal search result pages are not indexed | GSC - Coverage |
| The 404 page actually returns an HTTP 404 code, not a 200 | httpstatus.io |
Technical duplicate content
| Checkpoint | Verification tool |
|---|---|
| HTTP and HTTPS versions redirect to a single version | httpstatus.io |
| www and non-www versions redirect to a single version | httpstatus.io |
| URLs with and without trailing slash are canonicalized | Screaming Frog |
| Paginated content does not create duplication | Screaming Frog |
| Mobile and desktop versions are unified (responsive, no separate m. subdomain) | Mobile test |
Multilingual and multiregional sites
For agencies managing clients with sites in multiple languages (French, Dutch, German in Belgium for example), hreflang tags are essential to prevent language versions from cannibalizing each other in SERPs.
| Checkpoint | Verification tool |
|---|---|
| Hreflang tags are present on all relevant pages | Screaming Frog |
| Each hreflang URL is absolute and accessible | hreflang.org |
| The x-default hreflang tag is defined on the default page | Screaming Frog |
| Hreflang pairs are reciprocal (if A points to B, B points to A) | Screaming Frog |
Part 5: Structured data
Structured data (schema markup) allows Google to understand your content and display rich snippets in search results: stars, FAQ, prices, events, and more. These visual enhancements increase click-through rates without necessarily improving ranking, but the combined effect can be significant.
According to data published by Google, pages with FAQ schema can see their click-through rate increase by 20 to 30% thanks to questions displayed directly in the SERP. This is an opportunity that many developers miss due to unfamiliarity with JSON-LD format.
| Schema type | Recommended use | Potential impact |
|---|---|---|
| Organization / LocalBusiness | All pages (via header or footer) | Brand authority + Knowledge Panel |
| WebSite | Homepage only | Potential Sitelinks Search Box |
| Article / BlogPosting | Blog articles and guides | +15 to 25% CTR on average |
| FAQPage | Pages with question-answer sections | +20 to 30% CTR |
| BreadcrumbList | Breadcrumb navigation | Path display in SERP |
| Product | E-commerce product pages | Price and availability in SERP |
| Review / AggregateRating | Pages with customer reviews | Stars visible in search results |
Structured data checkpoints
| Checkpoint | Verification tool |
|---|---|
| Organization schema is implemented across the site | Rich Results Test |
| The appropriate schema is present on each page type | Rich Results Test |
| Structured data is in JSON-LD (Google-recommended format) | Chrome Inspector |
| No errors are reported in GSC - Enhancements | Google Search Console |
| Structured data does not contain misleading or fabricated information | Manual review |
| LocalBusiness schema includes address, phone and hours where relevant | Rich Results Test |
Using this checklist with your partner
Having a checklist is good. Knowing how to integrate it into a project workflow is even better. Here is how to use it effectively at each project phase.
Initial brief with the checklist
At the start of a project, share the complete checklist with your developer or partner. Identify points that need particular attention given the chosen architecture (WordPress, Next.js, static site). Agree on who is responsible for each section.
Mid-development review
At mid-project, go through the Foundations and HTML Structure sections. These points are easier to correct before development is finalized. Screaming Frog can crawl the staging site for an initial assessment.
Full pre-launch validation
Before going live, go through the entire checklist. Use Google Search Console (with property verification on staging), PageSpeed Insights and Rich Results Test. Document the scores for future reference.
Post-launch audit at 30 days
One month after launch, verify in Google Search Console that all important pages are indexed, Core Web Vitals are in the Good range, and no structured data errors are reported.
Quarterly review on active sites
Theme updates, new pages and code changes can reintroduce already-fixed issues. Schedule a quick review of critical points every three months on sites you follow.
What to expect from a good development partner
If you work with a white-label partner or a technical provider, these points should be part of the standard delivery, without having to specify them explicitly on each project.
Robots.txt and sitemap configured
The partner configures robots.txt and XML sitemap by default on every delivered project.
Clean redirects by default
HTTPS, www/non-www and deleted pages are handled with correct 301 redirects.
PageSpeed 90+ score on delivery
Core Web Vitals are within Google thresholds at delivery, not after a correction cycle.
Unique meta tags on every page
Each page has a distinct title and meta description, configurable by the SEO team.
Organization schema included
Basic structured data is implemented at no extra cost in every project.
Technical documentation delivered
A summary of technical and SEO choices is provided with each project.
If your current partner does not deliver these elements by default, that is a signal to take seriously. We have detailed the criteria for choosing a good development partner, including the technical aspects related to SEO. And if you are an SEO consultant considering offering development services to your clients, our article on why SEO agencies outsource web development gives a useful perspective on this model.
To understand how a developer's architecture choices directly impact your SEO results, the article on technical SEO foundations you are overlooking complements this checklist usefully.
Frequently asked questions
Conclusion
Technical SEO is not an option added after the fact: it is a foundation laid correctly from the start of development. This 5-part checklist, shared with your developer at the right moment, can make the difference between a site that stagnates and one that progresses steadily in search results.
The reality for SEO agencies, whether in Belgium, Swiss Romande or Luxembourg, is often the same: technical recommendations are correct, but their implementation remains partial because there is no clear process between consultant and developer. This checklist is that process.
If you are looking for a development partner who understands these requirements by default, without having to specify everything on each project, discover how our white-label web development service works. Your SEO recommendations deserve a developer who actually implements them.
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