Seoglen

By Guven Tuncay · Updated March 2026

How to Do a Technical SEO Audit: A Step-by-Step Guide

The complete process for auditing your site's technical health — from crawling and indexability to Core Web Vitals, structured data, and building a prioritised fix list.

TL;DR

A technical SEO audit is a systematic review of your site's infrastructure to find issues preventing search engines from crawling, indexing, and ranking your pages. Unlike a checklist, an audit is a structured process: crawl, analyse, prioritise, and create an action plan. This guide covers six steps, with a real-world example showing how one site recovered 52% organic traffic. A Technical SEO Audit (£4.99) runs this analysis automatically for any URL in seconds.

What Is a Technical SEO Audit?

A technical SEO audit examines the non-content elements of your website that affect search engine visibility. It answers one question: can search engines effectively discover, crawl, render, index, and rank your pages?

Think of it as a structural survey for a building. Before you worry about interior design (content and keywords), you need to know the foundation is solid.

It differs from an on-page audit (content, keywords, headings) and off-page audit (backlinks, authority). Most sites have issues they do not know about: a page tagged noindex, a blocked directory, a 4-second load time. These are invisible to the naked eye but measurably hurt rankings. The audit makes them visible.

Why Technical SEO Audits Matter

Technical SEO is the foundation everything else sits on. Great content and strong backlinks mean nothing if Google cannot crawl your pages.

Indexability Is Binary

A page is either indexed or it is not. If a noindex tag, robots.txt block, or misconfigured canonical prevents indexing, that page generates zero organic traffic. Studies show 20–30% of pages on the average site have indexability issues the owner is unaware of.

Speed Is a Ranking Signal

Core Web Vitals are a confirmed ranking factor. Pages that fail LCP, CLS, or INP thresholds are at a measurable disadvantage. A 1-second delay in load time can reduce conversions by up to 7%.

Mobile-First Indexing Is the Default

Google indexes the mobile version of your site. If your mobile experience has issues — slow loading, broken layouts, missing content — rankings suffer across all devices.

Technical Debt Compounds

Issues accumulate: migrations introduce broken redirects, CMS updates change URL structures, developers add noindex tags during staging and forget to remove them. Without periodic audits, these stack up until recovery takes longer.

How to Do a Technical SEO Audit (6 Steps)

This is the process, not a checklist of items. Each step involves gathering data and deciding what to do about it. For the item-by-item reference, see our technical SEO checklist.

1

Crawl Your Site

Every audit starts with a crawl. Use Screaming Frog, Sitebulb, or Seoglen's Technical SEO Audit to scan your site and get a complete picture of URL structure, response codes, meta tags, and internal links.

  • HTTP status codes — identify 404 errors, redirect chains, and server errors (5xx)
  • Orphan pages — pages with no internal links pointing to them (invisible to crawlers)
  • Redirect chains and loops — each hop dilutes link equity and slows discovery
  • Duplicate URLs — same content at multiple URLs (trailing slashes, HTTP vs HTTPS)
  • Crawl depth — important pages should be reachable within 3 clicks from the homepage
2

Check Indexability

Verify which pages Google can actually index — this is often where audits uncover their biggest wins.

  • Noindex directives — check for noindex tags added during development and never removed
  • Robots.txt rules — verify important directories are not blocked; test with Search Console’s robots.txt tester
  • Search Console coverage — review the “Excluded” tab for pages Google discovered but chose not to index
  • Canonical tags — ensure each page’s canonical points to itself unless intentionally canonicalising elsewhere
  • Sitemap vs index — compare sitemap pages against what Google has indexed; large discrepancies indicate problems

Indexability issues are the highest-priority findings. A blocked page cannot rank, period. Fix these before speed or mobile optimisation.

3

Analyse Site Speed and Core Web Vitals

Once pages are confirmed indexable, evaluate load speed. Core Web Vitals are Google's official metrics and carry ranking weight.

  • LCP (Largest Contentful Paint) — under 2.5s. Measures main content load speed. Culprits: unoptimised images, slow server response, render-blocking CSS/JS
  • CLS (Cumulative Layout Shift) — under 0.1. Measures visual stability. Culprits: images without dimensions, injected ads, late-loading web fonts
  • INP (Interaction to Next Paint) — under 200ms. Measures responsiveness. Culprits: heavy JavaScript, long main-thread tasks, unoptimised event handlers

Use PageSpeed Insights for lab data and Search Console for field data. Focus on pages that fail thresholds first. For budget-friendly monitoring, see our cheap SEO tools guide.

4

Review Mobile Experience

Google uses mobile-first indexing — the mobile version of your site is what gets crawled and ranked. A site that looks perfect on desktop but breaks on mobile is effectively broken for Google.

  • Responsive design — content should reflow across screen sizes without horizontal scrolling or overlapping elements
  • Tap targets — buttons and links need at least 48×48px spacing so users can tap accurately
  • Content parity — the mobile version must contain the same essential content as desktop; hidden content may be deprioritised
  • Viewport configuration — verify the viewport meta tag is correctly set (width=device-width, initial-scale=1)
  • Font readability — body text should be at least 16px on mobile without requiring pinch-to-zoom

Test key pages using Chrome DevTools device emulation. Complex layouts, forms, and interactive elements break most often on smaller screens.

5

Audit Structured Data and Schema Markup

Structured data triggers rich results — review stars, FAQ dropdowns, product prices, breadcrumbs. Missing or broken schema is a common audit finding.

  • Validate existing markup — use Google’s Rich Results Test to check every page type for errors and warnings
  • Check for missing schema — product pages without Product schema, blog posts without Article schema, FAQ sections without FAQPage schema
  • Verify breadcrumb markup — BreadcrumbList schema helps Google understand your site hierarchy and display breadcrumb trails
  • Test organisation schema — ensure your homepage includes Organisation or LocalBusiness schema with accurate contact data
  • Look for conflicts — competing schema types on the same page or mismatched data between schema and visible content causes Google to ignore markup

Rich results increase click-through rates by 20–30% on average. For more on how schema fits into the bigger picture, see our on-page SEO checklist.

6

Create a Prioritised Fix List

The audit is only useful if it produces action. Turn findings into a prioritised list.

  • Critical — prevents indexing or breaks the site: noindex on important pages, robots.txt blocks, broken HTTPS, 5xx errors. Fix immediately.
  • Warning — hurts rankings but does not prevent indexing: slow LCP, missing schema, poor tap targets, redirect chains. Fix within 1–2 weeks.
  • Informational — incremental best-practice improvements: missing alt text, suboptimal headings, minor CLS shifts. Address in regular maintenance.

Seoglen's Technical SEO Audit automates this — categorising issues by severity with AI-powered fix recommendations for each one.

Real-World Example: Maple & Fern Interiors

Here is how a technical audit works in practice. Meet Maple & Fern Interiors — an interior design e-commerce site selling furniture and homewares online.

The Problem

Maple & Fern had been publishing product pages and blog posts for two years but organic traffic had plateaued. They had never run a technical audit. The site looked fine visually, but traffic was flat despite consistent content production.

The Audit Findings (47 issues)

  • 12 product pages had noindex tags left over from a staging migration — zero organic visibility
  • 23 redirect chains (3–4 hops) from old URL restructuring never cleaned up
  • No Product schema on any product page — competitors had rich results; Maple & Fern had plain blue links
  • LCP of 4.8 seconds on mobile from unoptimised hero images averaging 2.4MB each

The Fix: Prioritised Over 4 Weeks

  • Week 1 (Critical): Removed noindex tags from 12 product pages, requested reindexing
  • Week 2 (Critical): Compressed images to under 200KB, added lazy loading — LCP dropped from 4.8s to 1.9s
  • Week 3 (Warning): Collapsed redirect chains to single-hop 301s, added Product schema site-wide
  • Week 4 (Informational): Added breadcrumb schema, fixed 80+ missing alt texts, improved headings

Result: Within 8 weeks, organic traffic increased 52%. Indexed pages went from 180 to 340. Product pages appeared with rich results for the first time, increasing click-through rates by 28%. The entire fix cycle cost less than one month of PPC spend.

Technical SEO Audit vs. Technical SEO Checklist

These serve different purposes and work best together.

The Audit: Periodic Deep-Dive

Run quarterly or after major changes. Crawl the entire site, analyse patterns, and produce a prioritised action plan. Reveals systemic issues you would never catch page by page — site-wide redirect chains, indexability problems across directories.

The Checklist: Ongoing Maintenance

A page-by-page reference used during publishing. Does it have a title tag? Is canonical set? Is schema implemented? Prevents new issues between audits.

How They Work Together

The audit cleans up the past; the checklist protects the future. For e-commerce-specific challenges, see our SEO for e-commerce guide.

Common Technical SEO Audit Mistakes

  • Skipping the crawl and auditing pages manually — spot-checks miss site-wide patterns. You catch a missing title tag on one page but miss 50 noindexed pages in a subdirectory. Always start with a full crawl.
  • Fixing everything at once without prioritising — not all issues carry equal weight. Spending a week on alt text while noindex tags block product pages is a misuse of time. Critical issues first.
  • Ignoring mobile — Google indexes the mobile version. If your mobile experience has issues the desktop version does not, you are auditing the wrong thing.
  • Running the audit but never creating the action plan — an audit without a fix list is just a report in a folder. Every audit should end with a clear, assigned, deadline-driven task list.
  • Only auditing once — technical issues reappear. CMS updates, new content, and server changes introduce problems at any time. Quarterly audits catch issues before they compound.
  • Confusing the audit with the checklist — checking items off a list is not an audit. An audit analyses patterns, identifies root causes, and produces strategic recommendations.

See also: our technical SEO checklist for maintaining health between audits and our SEO for small business guide for prioritising with limited time.

Frequently Asked Questions

What is the difference between a technical SEO audit and a technical SEO checklist?
A technical SEO audit is a periodic deep-dive into your entire site — you crawl every page, analyse the data, prioritise issues, and create an action plan. A checklist is a reference of items to verify on an ongoing basis. The audit is the process; the checklist is the tool you use during and between audits. Most sites benefit from a full audit quarterly and checklist spot-checks after every major change.
How long does a technical SEO audit take?
For a small site (under 500 pages), a thorough audit takes 2–4 hours including crawling, analysis, and documenting findings. Larger sites (5,000+ pages) can take a full day or more. Automated tools like Seoglen’s Technical SEO Audit reduce the data-gathering phase to seconds for individual URLs, but interpreting results and building the action plan still requires human judgement.
How often should I run a full technical SEO audit?
At minimum, once per quarter. Also run one after any major site change — a redesign, CMS migration, domain move, or large-scale content restructure. Between full audits, use a checklist for spot-checks whenever you publish or update content.
Can I do a technical SEO audit without expensive tools?
Yes. Google Search Console (free) covers indexability, Core Web Vitals field data, and crawl errors. PageSpeed Insights (free) analyses speed. Screaming Frog offers a free tier for up to 500 URLs. Seoglen’s Technical SEO Audit costs £4.99 per report and checks meta tags, performance, content, links, schema, and security in seconds.
What should I fix first after a technical SEO audit?
Fix critical issues first: pages blocked from indexing (noindex tags, robots.txt blocks), broken canonical tags, and severe Core Web Vitals failures. These directly prevent Google from ranking your pages. Warnings like missing alt text or suboptimal heading structure are important but less urgent. Work through your prioritised list from critical to informational.
Do technical SEO audits affect rankings directly?
Many technical issues have direct ranking impact. Indexability problems prevent pages from appearing at all. Core Web Vitals are a confirmed ranking signal. Mobile-friendliness affects mobile-first indexing. Structured data triggers rich results that increase click-through rates. Fixing these removes barriers that prevent your content from ranking to its potential.
What is the difference between a technical SEO audit and an on-page SEO audit?
A technical audit focuses on infrastructure: can search engines crawl and index your site, does it load fast, is it mobile-friendly? An on-page audit focuses on content: are you targeting the right keywords, are headings optimised, is the content comprehensive? Both are necessary — technical SEO is the foundation, and on-page SEO is the content layer built on top of it.

Sources & Further Reading

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