Technical SEO checklist before launching a website

Search rankings depend largely on a site's content and reputation, but one technical mistake is enough to cancel everything out: a whole site blocked by a forgotten line, duplicate pages, a disastrous response time. This checklist gathers the checks to run before going live, and on the day itself. Each point takes a few minutes to verify.

1. Indexing

• No forgotten noindex. Sites in development often carry one on every page. Check the source of several pages and the HTTP header: curl -sI https://mysite.com | grep -i x-robots.
• No blocking in robots.txt. A leftover Disallow: / prevents all crawling.
• An up-to-date XML sitemap, declared in robots.txt and in Search Console, containing only indexable pages.
• The staging environment closed off: password-protected or noindex, so it does not end up competing with the real site.

Details in getting your site indexed by Google.

2. HTTPS and addresses

• HTTPS everywhere, with a valid certificate and automatic renewal: see Nginx and Let's Encrypt.
• A single version of the site. Choose with or without www and permanently redirect (301) every other variant to it: http://, http://www., https://www.. Test them one by one:

for u in http://mysite.com http://www.mysite.com https://www.mysite.com; do
  curl -s -o /dev/null -w "$u -> %{http_code} %{redirect_url}\n" "$u"
done

• A canonical tag on every page, pointing to its official address.
• 301 redirects from old addresses if you are rebuilding an existing site. This is the point that loses the most traffic during a redesign: every old page that ranks well must redirect to its equivalent.
• A real 404 page that actually returns the 404 code, not an error page served with a 200 code.

3. Titles and tags

• A unique title per page, about 50 to 60 characters long, containing the page's main topic. Beyond that, Google truncates it in results.
• A unique meta description of about 150 to 160 characters. It does not directly affect ranking, but it drives clicks.
• A single H1 heading per page, then H2 and H3 in a logical order.
• Descriptive alt text on meaningful images.
• Sharing tags Open Graph (og:title, og:image) for a nice preview on social networks and Discord.
• The language declared in <html lang="en">, and hreflang tags if the site exists in several languages.

4. Content structure

• Every important page receives internal links from other pages, with descriptive link text rather than "click here".
• Readable addresses: /minecraft-server rather than /page?id=42.
• No near-empty pages: a page of a few dozen words has little chance of being indexed and weakens the whole site. Fewer, more complete pages are better.
• No duplicate content between several pages or several untranslated language versions.
• Important text in HTML, not only loaded later by JavaScript or embedded in an image.

5. Speed

Google measures the real visitor experience with the Core Web Vitals: LCP (display of the largest element, aim for under 2.5 s), INP (responsiveness to interactions, under 200 ms) and CLS (layout stability, under 0.1). Test the main pages with PageSpeed Insights.

• Server response time is the foundation: LCP can never be faster than it. Above 800 ms, the server is what to fix first. See optimising PHP-FPM and the Nginx cache.
• Images in the right format and size: WebP or AVIF, actual display dimensions, width and height declared to avoid layout shifts.
• Lazy loading of images below the fold, with loading="lazy", but never on the main image at the top of the page.
• Compression and browser caching enabled for static files.

6. Mobile

Google crawls and evaluates the mobile version of sites first. Check for the <meta name="viewport" content="width=device-width, initial-scale=1"> tag, no horizontal scrolling, text readable without zooming, buttons large enough for a finger, and that the mobile content is the same as on desktop.

7. Structured data

Structured data, in JSON-LD format, describes the page's content to search engines: organisation, breadcrumb, article, product, FAQ. It can enrich how the page appears in results. Two rules: it must match exactly what is visible on the page, and it is validated with Google's Rich Results Test.

8. Launch day

1. Remove any noindex and Disallow left over from development.
2. Check the redirects and the HTTPS certificate.
3. Add the site and its sitemap to Search Console, then request indexing of the home page and main pages.
4. Install privacy-friendly analytics to track visits from day one.
5. Over the following weeks, watch Search Console's Pages report and fix the errors it reports.

Frequently asked questions