Technical site audit

A technical site audit is a check of how the site works "under the hood": speed and Core Web Vitals, server response codes (404, 5xx), redirects, robots.txt and sitemap, HTTPS, the mobile version. Its goal is to find errors that stop buyers from using the site and search engines from crawling and indexing it.

In plain words

A technical audit answers the question "is the site in working order?". It doesn't assess copy and design; it checks whether pages open quickly on a phone, whether the layout "jumps", whether the server responds without errors, whether links lead nowhere, whether the connection is secure. For an online store this is directly tied to money: a slow product page or an error in the cart on mobile is a lost order.

What gets checked

1. Core Web Vitals

Core Web Vitals are three Google metrics that describe real user experience (web.dev):

Sources for the thresholds: LCP, INP, CLS.

How it is assessed. A page passes if at the 75th percentile of page views all three metrics are in the green zone; mobile and desktop data are counted separately (web.dev). That is, it is not the best experience that counts but a fairly bad one: three out of four visitors must get "good".

INP instead of FID. INP is the successor to the First Input Delay metric; it became a stable Core Web Vital in 2024 (web.dev, web.dev/inp).

What typically breaks the metrics in a store: - LCP — a large main product photo or a banner on the homepage. On a product page the LCP element will most often be the photo. - CLS — images without set dimensions, web fonts that render larger or smaller than the fallback font, third-party widgets and ads that change size after loading, content inserted above what is already visible (a "free delivery" banner above the header) (web.dev/cls). Shifts within 500 ms of a user action (for example, expanding a filter) don't count toward CLS (same source). - INP — heavy scripts: chats, analytics, review widgets, complex JavaScript filters.

2. Response codes: 404, 5xx, "soft 404s"

How Google handles response codes (Google Search Central):

• 4xx (except 429), including 404 and 410 — the content is considered non-existent, the page is removed from the index, and crawling of that address gradually thins out.
• 429 and 5xx — a signal of server overload: Google slows crawling; if errors persist, indexed pages eventually drop out.
• Soft 404 — a page responds with code 200 but shows an error or empty content. In stores these are often empty categories and pages of discontinued products.

The audit looks for: internal links to 404s, pages with 5xx (often search and filters under load), soft 404s.

3. Redirects

• By default Google follows up to 10 redirect hops (Google), but for large sites it advises avoiding long chains (Google, crawl budget).
• 301 and 308 are a strong signal that the main address is the target; 302, 303 and 307 are a weak one (Google). Permanent moves (old URLs after a platform change) are done with 301.
• http, https, www and non-www must all lead to one version of the site.

4. robots.txt and sitemap

• robots.txt controls crawling so the site isn't overloaded with requests. It doesn't hide a page from search: for that you need `noindex` or a password (Google). Check that the CSS, JS and images needed for rendering aren't blocked, and that junk addresses (filters, sorting, cart) are.
• A sitemap is needed by large sites, new sites with few external links and sites with many videos or images; a site of up to roughly 500 pages with good internal linking may not need one (Google). An online store with a catalog usually does.

5. Security

• HTTPS on all pages, with no mixed content. Google recommends serving pages securely and checking this in the HTTPS report in Search Console (Google, page experience).
• An up-to-date CMS and plugins, a protected admin, backups. These aren't Google's items, but without them the rest of the audit is pointless: a hacked store can distribute spam or viruses.

6. Mobile version

Google indexes a site by its mobile version. So mobile pages must contain the same main content, the same structured data (above all Breadcrumb and Product) and the same title and description as desktop ones; content that appears only after a swipe, click or text input may not be seen by Google (Google, mobile-first indexing). Google also advises avoiding intrusive pop-ups that cover content (Google, page experience).

How different sources see it

• web.dev (the Chrome team) treats Core Web Vitals as the quality of user experience, independent of SEO.
• Google Search Central clarifies: Core Web Vitals is the only page experience aspect directly used by ranking systems; HTTPS, mobile friendliness and the absence of intrusive pop-ups don't directly affect rankings but make the site more convenient. High scores don't guarantee top positions, and chasing perfect numbers purely for SEO may not be worthwhile (Google).

Common mistakes

• Looking only at the PageSpeed Insights score from a lab test. Core Web Vitals thresholds are calculated from real user data at the 75th percentile.
• Checking only the homepage. In a store the templates matter more: category, product page, cart, checkout.
• Testing from office Wi-Fi on a powerful laptop. Buyers come from phones on mobile internet.
• Blocking pages with 401/403 to reduce Googlebot load. These codes don't affect crawl rate (Google).
• Not setting up 301s from old addresses after moving to a new platform.

FAQ

What is a technical site audit? A check of the site's technical condition: speed and Core Web Vitals, server errors, redirects, robots.txt and sitemap, HTTPS and the mobile version.

Which Core Web Vitals values are considered good? LCP up to 2.5 s, INP up to 200 ms, CLS up to 0.1 — at the 75th percentile of page views, separately for mobile and desktop.

How does a technical audit differ from an SEO audit? A technical audit checks that the site is in working order. An SEO audit includes the technical items that affect search, plus content, queries, structure and links. See SEO audit of an online store.

When should I run a technical audit? Before launch and after a redesign or move to a new platform, when traffic or mobile conversion drops, and after connecting new third-party scripts.

Related terms

• SEO audit of an online store
• Technical specification for an online store
• E-commerce

Sources

• web.dev, Web Vitals — web.dev/articles/vitals
• web.dev, Largest Contentful Paint (LCP) — web.dev/articles/lcp
• web.dev, Interaction to Next Paint (INP) — web.dev/articles/inp
• web.dev, Cumulative Layout Shift (CLS) — web.dev/articles/cls
• Google Search Central, HTTP status codes, network and DNS errors — developers.google.com/search/docs/crawling-indexing/http-network-errors
• Google Search Central, Large site owner's guide to managing your crawl budget — developers.google.com/search/docs/crawling-indexing/large-site-managing-crawl-budget
• Google Search Central, Introduction to robots.txt — developers.google.com/search/docs/crawling-indexing/robots/intro
• Google Search Central, Sitemaps overview — developers.google.com/search/docs/crawling-indexing/sitemaps/overview
• Google Search Central, Understanding page experience — developers.google.com/search/docs/appearance/page-experience
• Google Search Central, Mobile-first indexing best practices — developers.google.com/search/docs/crawling-indexing/mobile/mobile-sites-mobile-first-indexing