A technical SEO audit that tells you why search engines can't see your site

A technical SEO audit is a focused diagnosis of the engineering and infrastructure factors that decide whether search engines can crawl, render, index, and rank a website. The Illucrum technical audit reviews crawlability and indexation, site architecture, JavaScript rendering, Core Web Vitals and performance, structured data, canonicalisation, and crawl budget. The output is a written report with scored severity and prioritised fixes, delivered in 3 to 5 business days. It is the engineering layer only; it does not include keyword strategy, content, or competitor analysis.

• 01

  Large or complex sites

  Sites with thousands of URLs, where crawl budget, index bloat, and architecture quietly suppress rankings.

• 02

  JavaScript-heavy applications

  Single-page apps and client-rendered sites where content the user sees never makes it into the index.

• 03

  After a migration or replatform

  When redirects, canonicals, and indexation need verifying before traffic erodes.

• 04

  Sites with an unexplained drop

  Where rankings or indexed pages fell and you need a prioritised technical backlog, not a full strategy review.

If you need keyword strategy, content depth, and competitor positioning as well, a full audit is the closer fit: the SaaS SEO audit, e-commerce SEO audit, or website SEO audit each include the technical layer plus the strategic sections this focused audit leaves out.

1. Crawlability and indexation

   Robots configuration, XML sitemaps, crawl directives, index bloat, noindex and canonical conflicts, orphan pages, and the gap between what is submitted and what is actually indexed. Most quiet ranking suppressors hide here.

2. Site architecture and internal linking

   Click depth, the distance of money pages from the homepage, internal link equity distribution, navigation structure, and whether the most important pages are reachable and reinforced.

3. JavaScript rendering

   Client-side versus server-side rendering, hydration, and the routes that render fine for a user but return empty HTML to a crawler. A common cause of quietly de-indexed app subdomains.

4. Core Web Vitals and performance

   Largest Contentful Paint, Interaction to Next Paint, Cumulative Layout Shift, render-blocking resources, and mobile performance, where most traffic now sits.

5. Structured data

   Schema validity, coverage gaps, and eligibility for rich results. Where markup is malformed or missing on templates that could earn enhanced listings.

6. Canonicalisation and duplicate content

   Canonical handling, parameter and faceted URLs, pagination, www versus non-www, trailing-slash and protocol consistency, and the duplicate clusters that split ranking signals.

7. HTTPS, redirects, and status codes

   Mixed content, redirect chains and loops, 4xx and 5xx errors, soft 404s, and the wasted crawl equity they create.

8. Crawl budget and international signals

   Crawl-budget efficiency on large sites, log-file signals where available, and hreflang and locale targeting where the site serves more than one region.

• 01

  Client-rendered content the crawler never sees

  A JavaScript app where the key landing pages render only after hydration; the crawler receives an empty shell and the pages never index.

• 02

  Index bloat from parameter URLs

  Thousands of filtered and sorted URL variants indexed alongside the canonical, splitting signals and burning crawl budget.

• 03

  Redirect chains after a migration

  Old URLs hopping through three or four redirects before landing, leaking equity and slowing the crawl at every step.

• 04

  Canonical pointing at the wrong page

  Templated canonical tags hard-coded to the homepage, telling search engines to ignore every other page on the template.

• 05

  Core Web Vitals failing on mobile

  Largest Contentful Paint well over budget on mobile, with mobile being 60%+ of the site's traffic.

• 06

  Broken hreflang clusters

  Hreflang annotations that don't return reciprocal tags, so locale targeting silently fails and the wrong region's pages rank.

The report is specific to the site. No filler.

Need keyword, content, and competitor depth as well? A full audit includes the technical layer plus the strategic sections: see the website SEO audit, SaaS SEO audit, or e-commerce SEO audit.

For pricing across every audit type, see the pricing page.

1. Intake

   A short brief: the site URL and the technical question you want answered. WhatsApp or email; no calls required.

2. Crawl and tooling

   The site is crawled and analysed across Google Search Console, PageSpeed Insights, a rendering check, and structured-data validators, with log files where available.

3. Manual review

   Every check is verified by hand. AI-assisted scoring is used for triage, not for final answers.

4. Report

   A written PDF report with scored findings, prioritised fixes, and a technical action plan.

Full process detail at How an Illucrum SEO audit takes shape.

• 01

  One person, one process

  Every audit is delivered by the founder; nothing is offshored or templated.

• 02

  Interpretation, not a tool dump

  A crawler lists every issue; this audit ranks them by impact and tells you what to fix first.

• 03

  Source-backed methodology

  Every benchmark referenced in the report has a citable source. See SEO facts and statistics.

• 04

  Written-first delivery

  No retainer trap, no sales call, no calendar block.

See the general SEO audit questions for more.

Still deciding? See which SEO audit is right for you.