SEO Audit: The Complete Method (+ Checklist)

*By Timothy Jacqmin — Co-Founder, Nexuro Digital · July 2026*

TL;DR

• An SEO audit is the complete diagnosis of your website: it explains why you don't rank (or not enough) on Google and in AI engines, and above all what to fix first.
• It runs across 5 layers: technical (can Google read your site?), on-page (do your pages answer the right questions?), content (what to keep, merge, delete?), off-page (does your site look trustworthy?) and GEO (are you cited by ChatGPT and Perplexity?).
• The golden rule: always start with the technical layer. Without indexing, the best content in the world stays invisible.
• The goal is not a list of 200 problems, but a prioritized action plan (P0/P1/P2) tied to one question: is it bringing you customers?
• You can start alone with free tools (Search Console, Screaming Frog). The checklist at the bottom gives you the points to tick, in the right order.

Your site has been live for months. You publish, you wait. But the traffic doesn't come, or it comes and doesn't convert. Before adding another page or launching a campaign, you need a diagnosis. That is what an SEO audit is for.

At Nexuro, we don't run on gut feeling. An audit isn't a hunch about "what's wrong," it's a method. We check specific points, in a specific order, and tie every finding to a business impact. Here is exactly how we proceed, and how you can start yourself.

What is an SEO audit?

An SEO audit is the structured diagnosis of a website that evaluates everything influencing its visibility in search engines (Google, Bing) and, now, in generative engines (ChatGPT, Perplexity, Google AI Overviews). Its purpose is not to grade your site, but to find what stops it from ranking and to prioritize the high-impact fixes.

An SEO audit answers three simple questions. Can Google crawl and read your site? Does your content actually answer what your customers search for? Do other sources see you as credible? Until those three answers are clear, investing in more content or more ads is like filling a leaky bucket.

Key takeaway: the audit comes before the action. You don't build on foundations you haven't inspected. A proper audit stops you from spending a content budget on pages Google doesn't even index.

What are the layers of a complete SEO audit?

A complete SEO audit covers five complementary layers: technical, on-page, content, off-page and GEO. Each answers a different question, and none is enough on its own. A technically perfect site with no useful content won't rank any more than great content Google can't crawl.

Most "free" automated audits stop at layer 1 and spit out a list of 200 errors with no priority. A real audit ranks them. We classify each problem as P0 (blocking, fix now), P1 (high impact) and P2 (optimization). That prioritization is what turns a diagnosis into an action plan.

Layer 1 · The technical audit: can Google read your site?

This is the starting point, and the one everyone skips. A page Google can't crawl or doesn't index simply doesn't exist in the results, whatever its content. So we always start with the foundations, in this order.

1. Indexing. How many of your pages are actually in Google's index? The "Pages" report in Google Search Console tells you exactly which are indexed, which are excluded, and why. The quick test site:yourdomain.com gives a first idea.
2. Crawl and crawl budget. A crawler like Screaming Frog (free up to 500 URLs) walks your site like Googlebot and surfaces 404 errors, redirect chains, orphan pages and missing tags.
3. Speed and Core Web Vitals. Google measures three official page-experience signals: LCP (loading, good under 2.5s), INP (responsiveness, good under 200ms, the metric that replaced FID in March 2024) and CLS (visual stability, good under 0.1).
4. Mobile and HTTPS. Google indexes your site in its mobile version (mobile-first). A non-responsive or non-secure site (no HTTPS) starts with a handicap.
5. Structured data (Schema.org). This invisible markup tells Google the nature of your content (organization, FAQ, product, review) and unlocks rich results.

Common mistake: believing "the site loads fast for me" is enough. Google judges on field data (real users), not on your office fiber. We measure with the right tools, we don't guess.

Layer 2 · The on-page audit: do your pages match the right intent?

Once your pages are readable by Google, we look at what they say. The on-page audit checks that each page targets a clear search intent and answers it better than the pages already ranking. A large part of your positioning is decided here.

Page by page, we review:

• The title tag and meta description. Unique, under 60 and 155 characters, containing the keyword and a promise. This is your storefront in the results.
• The heading structure. One clear H1, H2s that mirror the real questions users ask, a logical hierarchy.
• Intent match. Does the page answer what the user truly wants (information, comparison, purchase)? A "service" page that reads like a blog post misses its target.
• Internal linking. Do your pages cite each other with descriptive anchors? Internal links pass authority and guide Google.
• Images. ALT attribute filled, optimized weight, modern format.

The rule we repeat to every client: one page = one intent. Ten topics on one page dilute the signal. Ten clean pages beat one catch-all page. To go further on building a keyword strategy, see our guide on where to start with SEO.

Layer 3 · The content audit: what to keep, merge or delete?

Content isn't "always more." A content audit identifies pages that perform, pages that are dead, and pages that cannibalize each other. On a site that has been running for a few years, a large share of pages no longer contributes anything, and some drag the whole site down.

For each URL we cross the data from Search Console (clicks, impressions, 3-month position) and your analytics (sessions, conversions). Three possible verdicts:

• Keep and strengthen: the page performs or has potential. We enrich and update it.
• Merge: two pages target the same keyword and compete (cannibalization). We combine them into one stronger page, with a 301 redirect.
• Delete or deindex: the page has no traffic, no conversion, no purpose. It dilutes the site's perceived quality.

Key takeaway: a smaller but 100% useful site often ranks better than a large, half-dead one. Perceived quality is judged across the whole site, not page by page.

Layer 4 · The off-page audit: does your site look trustworthy?

Google doesn't rely only on what you say about yourself. The off-page audit measures your site's authority as seen from outside: who links to you, with what links, and with what credibility. This is the third pillar, often the slowest to build.

We look at:

• The backlink profile. How many sites link to you, which ones, and above all their quality. Ten links from reference sites beat a thousand shady ones.
• Quality and relevance. A link from a thematically close site (your sector, your region) weighs more than a generic one.
• Toxic links. A profile polluted by spam can hold back your progress. We identify what should be disavowed.
• Local presence. For an SME, the Google Business Profile, local directory citations and customer reviews are decisive on geolocated searches.

Off-page is the layer where you progress the slowest, but also the one that best protects your positions over time. It's an asset, not a shortcut.

Layer 5 · The GEO audit: are you cited by ChatGPT and Perplexity?

This is the layer 90% of audits still ignore. More and more, your customers no longer type their question into Google: they ask ChatGPT, Claude or Perplexity, which answer with two or three cited sources. The new question is no longer just "do I rank?", but "am I the source the AI cites?".

Good news: strong SEO is the best starting point for GEO. A GEO audit looks at signals that largely overlap classic SEO, with a few specific requirements:

• Content citability: direct answers at the top of paragraphs, TL;DR, question-style subheadings, structured content the AI can extract effortlessly.
• Structured data (FAQPage, Article, HowTo) that helps engines understand and reuse your content.
• Off-page presence on the third-party sources AIs consult (reference content, forums, specialized press).

This is our pioneering ground in Belgium. If you want to understand this shift in detail, we wrote a complete guide: how to be visible in ChatGPT, Claude and Perplexity.

The SEO audit checklist to tick

Here is the summary checklist we use internally. Work through it top to bottom: the layers are ordered from the most blocking (technical) to the slowest to build (off-page/GEO). Tick, prioritize, act.

Recommendation: don't try to tick everything on day one. Handle the P0s, then the P1s. An audit that stays in a drawer is worthless. An audit whose first 5 points get executed is gold.

Which tools to run an SEO audit?

You can start a serious SEO audit with free tools, before any paid investment. Here is the basic toolkit we recommend to an owner who wants clarity.

• Google Search Console (free): Google's official dashboard. Indexing, queries, positions, clicks, Core Web Vitals. A mandatory starting point.
• Screaming Frog SEO Spider (free up to 500 URLs): the crawler that walks your site like Googlebot and surfaces errors, redirects, tags and structure.
• PageSpeed Insights / web.dev (free): to measure Core Web Vitals on field data.
• Google Analytics (GA4) (free): to cross traffic with real conversions. Reliable conversion data depends on clean tracking, a topic we detail in our article on server-side tracking.

Paid tools (Ahrefs, Semrush) mainly add depth on off-page and keyword tracking. Useful, but not essential for a first diagnosis. The tool doesn't make the audit: interpretation and prioritization create the value.

Should you run your SEO audit yourself or delegate it?

An owner can run a first surface-level audit alone; a deep audit (technical + off-page + trade-offs) is better delegated. Checklist points 1 to 6 are accessible with Search Console and a bit of method. Beyond that, link-profile analysis, cannibalization detection and, above all, prioritization take experience.

The real risk of DIY isn't a technical error, it's the wrong trade-off: spending three weeks optimizing images while your key pages aren't indexed. An outside eye quickly sees what actually blocks. On the role and cost of support, we detailed when to hire an SEO consultant and what the price of SEO in Belgium looks like.

FAQ

What is an SEO audit?

An SEO audit is the complete diagnosis of a website that evaluates everything influencing its visibility on Google and in generative engines. It covers five layers (technical, on-page, content, off-page, GEO), identifies what blocks ranking and leads to a prioritized action plan. Its goal is not to grade the site, but to say what to fix, and in which order.

How do you run an SEO audit yourself?

Start with the technical layer. Open Google Search Console and check which pages are indexed. Then run a crawler like Screaming Frog (free up to 500 URLs) to spot 404 errors, redirects and missing tags. Check Core Web Vitals, then your titles, H1s and internal linking. Work the checklist top to bottom, from the most blocking to the most optional.

How much does an SEO audit cost?

The price varies with the site's size and the depth expected. A surface audit can be done for free with tools like Search Console. A deep professional audit (technical, content, off-page, GEO, prioritized action plan) is usually billed per project or in consulting days. At Nexuro, the audit of your digital ecosystem is free and with no commitment.

How long does an SEO audit take?

Expect a few hours for a surface diagnosis to several days for a deep audit of a mid-sized site. Data collection (crawl, 3-month Search Console data) is fast. It's the analysis, the trade-offs and writing a prioritized action plan that take the most time. A larger, older site requires more analysis.

How often should you audit your site?

At least once or twice a year for a stable site, and every quarter for a site that grows fast, publishes a lot, or operates in a competitive sector. A one-off audit fixes what exists; regular monitoring prevents regressions (deindexed pages, broken links, outdated content) before they cost you positions.

Does an SEO audit cover GEO (ChatGPT, Perplexity)?

A modern audit should. Your customers increasingly ask ChatGPT, Claude or Perplexity, which cite two or three sources. The GEO audit checks your content's citability (direct answers, FAQ, structured data) and your presence on the sources AIs consult. Good news: solid SEO content is already an excellent starting point for GEO.

Conclusion

An SEO audit isn't a technical formality. It's the diagnosis that stops you from spending a marketing budget on cracked foundations. The method is always the same: technical first (can Google read you?), then content (do you answer the right questions?), then authority (are you trusted?), and finally GEO (do AIs cite you?). Every finding tied to the one question that matters: is it bringing you customers?

Don't chase perfection on day one. Tick the blocking points, fix, measure. An audit that stays in a drawer is worthless; an audit whose first lines get executed changes a site's trajectory.

*Want to know what's really holding your site back before investing more? We can look at it together, simply, in a free audit of your digital ecosystem. No bots, no salespeople: Timothy or Bryan replies to you personally within 24h.*

*— Timothy Jacqmin, Co-Founder, Nexuro Digital*

Sources

• Google (web.dev) — *Web Vitals* (LCP, INP, CLS and thresholds): https://web.dev/articles/vitals
• Google (web.dev) — *Interaction to Next Paint (INP)*, the metric that replaced FID in March 2024: https://web.dev/articles/inp
• Google Search Central — *Structured data / rich results*: https://developers.google.com/search/docs/appearance/structured-data/intro-structured-data
• Google Search Central — *Search Console* (official help): https://support.google.com/webmasters/answer/9128668
• Screaming Frog — *SEO Spider* (crawler, free version up to 500 URLs): https://www.screamingfrog.co.uk/seo-spider/