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Many business websites lose visibility quietly over the years: pages drop out of the index, load times creep up and content goes stale. An SEO audit brings these problems to light before they cost you enquiries. This article explains what an audit checks, what the results look like and when an audit is worth doing.
What is an SEO audit?
An SEO audit is a systematic review of how well search engines can find, understand and recommend your website. Rather than checking a handful of rankings, it looks at the whole site: technology, speed, content and signals from outside your own pages.
The goal is not a list of hundreds of warnings. It is a clear answer to two questions: what is currently stopping the site from being found, and which actions deliver the biggest impact for reasonable effort?
The areas an audit covers
Technical: crawling and indexing
Search engines use programs called crawlers to fetch and analyse pages. The technical part of the audit checks whether those crawlers can reach all important pages and whether those pages are allowed into the search index. Typical questions include:
- Crawling: Does robots.txt accidentally block important sections? Are there broken links, redirect chains or error pages?
- Indexing: Are pages that should rank marked "noindex"? Conversely, are filter, test or login pages being indexed?
- Canonicals: A canonical tag tells search engines which of several similar URLs is the authoritative one. Misconfigured canonicals can make entire sections invisible.
- XML sitemaps: A sitemap lists the pages you want indexed. It should be complete and free of redirected or blocked URLs.
- hreflang: On multilingual sites, the hreflang attribute signals which language version is meant for which audience. Broken references lead to the wrong language showing in search results.
- Security headers: HTTPS is mandatory. The audit also checks headers such as Strict-Transport-Security and Content-Security-Policy. They are not a direct ranking factor, but they are part of running a site properly.
Core Web Vitals
Core Web Vitals are three Google metrics that measure user experience while a page loads and responds. Google assesses the 75th percentile of page views, meaning the value that three quarters of visits meet or beat.
| Metric | What it measures | Good | Poor |
|---|---|---|---|
| LCP (Largest Contentful Paint) | Load time of the largest visible element | up to 2.5 seconds | over 4 seconds |
| INP (Interaction to Next Paint) | Response time to clicks and input | up to 200 milliseconds | over 500 milliseconds |
| CLS (Cumulative Layout Shift) | Content shifting while loading | up to 0.1 | over 0.25 |
Values in between are rated "needs improvement". Where possible the audit uses real user data (field data), backed by lab measurements that reveal the causes, such as oversized images, render-blocking scripts or missing placeholders for banners.
Content and E-E-A-T
E-E-A-T stands for Experience, Expertise, Authoritativeness and Trustworthiness. Google uses these terms in its guidelines to describe helpful content. The audit checks whether your pages answer your customers' real questions, whether it is clear who stands behind the content, and whether legal notice, contact details and references are easy to find.
It also covers the basics: unique page titles and meta descriptions, a logical heading structure, no duplicate or very thin pages, and sensible internal linking.
Structured data
Structured data is machine-readable information in your source code, usually in JSON-LD format using the Schema.org vocabulary. It helps search engines identify your company name, address, products or articles unambiguously. The audit checks that the markup is error-free, matches the visible content and suits your page types.
Images
Images are often the biggest drag on load time. The audit reviews file sizes, modern formats such as WebP or AVIF, responsive image sizes, lazy loading and fixed dimensions that prevent layout shifts. It also checks for meaningful alt text, which supports accessibility as well.
Local search
For businesses serving a regional market, local search is often the most important channel. The audit looks at your Google Business Profile, consistency of name, address and phone number across your site and directories, location pages and reviews.
AI visibility
A growing share of searches are answered by AI, for example in Google AI Overviews or ChatGPT. The audit checks whether the relevant crawlers may access your pages, whether content is available as plain text rather than locked in images or scripts, and whether key statements make sense as standalone passages. Nobody can guarantee that your business will be mentioned in AI answers.
The outcome: health score and action plan
An audit produces two things. The health score summarises the state of the site in a single number, usually on a scale up to 100, broken down by area. It is useful for comparing progress between audits.
More important is the prioritised action plan. Each recommendation is ranked by impact and effort, for example:
- Critical: Issues that keep pages out of the index or block users, such as an accidental "noindex" on the home page.
- High: Actions with noticeable impact, such as poor Core Web Vitals on key landing pages.
- Medium: Improvements such as missing structured data or duplicate page titles.
- Low: Polishing that can be handled alongside other work.
This lets you and your development team work in a focused way instead of chasing individual warnings.
When is an SEO audit worth it?
An audit is not a one-off. Websites change through new content, plugin updates and hosting changes, and search engine requirements keep evolving. The following rhythm has proven effective:
- Full audit once or twice a year: Every area is examined thoroughly and the action plan is updated.
- After every relaunch: A relaunch often changes URLs, templates and technology. An audit right after go-live reveals missing redirects and indexing errors before rankings are lost. Ideally, check the staging environment before launch as well.
- Quarterly check: A compact look at indexing, Core Web Vitals and error pages, for example using Google Search Console.
- After website updates: Review major changes to themes, plugins or page templates specifically, because they can silently affect canonicals, meta tags or load times.
An audit is also worthwhile if enquiries through your website drop for no obvious reason, or if you want new services or locations to become visible.
Checklist: preparing for an audit
- Provide or set up access to Google Search Console
- Clarify access to your analytics tool
- List the key pages and services you want to be found for
- Mention planned changes or an upcoming relaunch
- Name contacts for technology and content
- Have the results of your last audit ready, if available
SEO audits at Simplify Data
Simplify Data carries out SEO audits for companies in Kiel, Schleswig-Holstein and Hamburg, and remotely across Germany. You receive a health score and a prioritised action plan, which we can implement together with you if you wish. Request an SEO audit