Technical SEO: indexing, speed and mobile without coding

Technical doesn't mean for developers

The word "technical" scares people off, wrongly. Technical SEO isn't about coding: it's about removing the obstacles that prevent Google from crawling, indexing and correctly displaying your site, and giving visitors a fast, comfortable page. Most settings are done in your CMS interface, via a plugin, or by reading a report. The stakes are asymmetric: a single technical problem can sink a whole site, whereas a technically sound site lets content and authority express themselves fully.

Check indexing: the most important GSC report

Your first technical mission is to know which pages Google has actually indexed. Search Console's Page indexing report lists included pages and, above all, excluded ones with the reason: "noindex detected", "blocked by robots.txt", "crawled, currently not indexed", "duplicate without canonical"… Each reason is a diagnosis. The URL Inspection tool (still in GSC) goes further: it tells you, page by page, whether it's indexed, when it was last crawled, and lets you request indexing after an update. It's free, and it's the reflex to have as soon as a page doesn't appear.

Core Web Vitals: speed turned criterion

Google measures the loading experience through three indicators, the Core Web Vitals: LCP (time to display the main content), INP (responsiveness to interactions) and CLS (visual stability, the absence of content that "jumps"). Two free tools measure them: PageSpeed Insights (enter a URL, get a score and recommendations) and Search Console's Core Web Vitals report (site overview). Speed isn't just a ranking factor: a slow page scares visitors off before it's even read. On mobile, every second counts double.

Concretely speeding up a slow site

The most common causes of slowness, and their accessible remedies:

On WordPress, a plugin like WP Rocket (~€50/year) handles caching, compression and lazy loading at once. On Webflow, Shopify or Wix, many optimizations are already built in: you then focus mainly on image weight.

Mobile first: the mobile-first index

Google indexes and ranks sites based on their mobile version (mobile-first indexing). If your site looks great on desktop but is unreadable on a phone — tiny text, buttons too close together, cut-off content — that's the degraded version Google evaluates. Test on a real phone, and check the mobile tab in PageSpeed Insights. Most modern themes and builders are "responsive" by default, but a real check avoids nasty surprises. The reflex: design and proofread for the thumb, not the mouse.

HTTPS, canonicals and redirects: the silent foundations

Three technical elements go unnoticed when they work, and cost dearly when they're missing. HTTPS (the padlock) is a prerequisite: a plain-HTTP site inspires distrust and is penalized — most hosts provide a free certificate (Let's Encrypt). Canonical tags (rel=canonical) tell Google which is the "official" version of a page that exists at several URLs (with/without www, sorting parameters…), avoiding duplicate content. 301 redirects preserve SEO when a URL changes: without them, you send visitors and Google to a 404 error page, and lose the work done.

Crawling at scale: Screaming Frog

For a site beyond a few dozen pages, a crawler simulates Googlebot's pass and reveals all problems at once. Screaming Frog SEO Spider is the reference: free up to 500 URLs, ~€239/year beyond. In one analysis, it lists error pages (404, 500), redirect chains, missing or duplicate titles, forgotten noindex tags, broken links, images without alt. It's the tool for periodic technical audits — useless day to day, valuable once or twice a year or before a redesign.

Structured data: helping Google enrich your results

Structured data (Schema.org vocabulary) is invisible code that precisely describes content: a review, a price, a recipe, a FAQ, an event, a local business. Well placed, it lets Google display rich results (review stars, prices, expandable questions) that catch the eye and raise click-through rate. On WordPress, RankMath or Yoast generate it automatically for common types; Google's free Rich Results Test validates your markup. It's not a launch priority, but it's a real visibility gain once the basics are in place.

Technical discipline: check after every big change

Technical SEO isn't a job done once and for all. Every redesign, theme change, migration or mass page addition can break something silently. The healthy reflex: after any major change, take a tour of Search Console (indexing, Core Web Vitals), inspect a few key URLs, and run a crawl if the site is large. A few minutes of checking prevent weeks of lost traffic with no explanation.