SEO Audit: 15 Things Your Agency Should Check

Most websites are leaving traffic, leads, and revenue on the table, and the business owners have no idea why. Search engines are crawling your pages right now, and if your site has unresolved technical issues, thin content, or broken signals, your rankings will reflect that. A thorough SEO audit is the single most important first step any serious agency takes before launching a strategy.

Below is a detailed breakdown of the 15 most critical checks your agency should run during every SEO audit. Whether you are an in-house marketer reviewing performance or a business owner evaluating an agency proposal, this list gives you a clear benchmark for what a proper audit should cover.

Why a Proper SEO Audit Matters Before Any Strategy

Running paid ads or publishing content on a broken website is like building on sand. Before recommending a single tactic, a qualified agency needs to know exactly where your site stands technically and content-wise. A structured SEO audit services process removes guesswork and creates a performance baseline that informs every decision going forward.

The 15 Essential SEO Audit Checks Every Agency Should Run

1. Crawlability and Indexation Status

Your agency should start by confirming search engines can actually crawl and index your site. This means checking your robots.txt file for accidental blocks, reviewing the XML sitemap for broken or excluded URLs, and identifying any noindex tags applied to important pages. Even one misconfigured directive can wipe out rankings overnight.

2. Technical Error Audit (4xx and 5xx Codes)

Broken pages send negative signals to Google and frustrate real visitors. A comprehensive audit scans for 404 errors, server errors (500), and redirect chains that slow crawling. These technical fixes are often low-effort, high-reward wins that most agencies handle early in the process.

3. Site Speed and Core Web Vitals

Google confirmed Core Web Vitals (LCP, INP, and CLS) as ranking signals. Your agency should measure page load times across both desktop and mobile, identify render-blocking resources, oversized images, and poor server response times. Improving speed directly impacts both rankings and conversion rates.

4. Mobile-Friendliness and Responsive Design

With Google operating on a mobile-first index, a site that does not perform well on smartphones is already behind. The audit should test every key page template across device sizes, check tap targets, font sizes, and layout stability on smaller screens.

5. HTTPS and Site Security Signals

Google treats HTTPS as a ranking factor. The audit should confirm your SSL certificate is active and correctly installed, that all HTTP pages redirect to their HTTPS equivalents, and that there are no mixed-content warnings that would undermine trust signals.

6. On-Page Optimisation Review

This is where your agency examines each page’s title tags, meta descriptions, H1 tags, and heading hierarchy. Missing or duplicated title tags and meta descriptions dilute your relevance signals. Every priority page should have a unique, keyword-rich title tag under 60 characters and a compelling meta description under 160. A thorough on-page SEO optimisation review finds these gaps fast and is foundational to any ranking improvement.

7. Keyword Mapping and Cannibalisation Check

When multiple pages target the same keyword, they compete against each other and confuse search engines about which page to rank. A keyword mapping audit identifies cannibalisation issues and determines which URL should own each target term, allowing for strategic consolidation or differentiation of content.

8. Content Quality and Thin Page Audit

Low-quality or thin content pages are a major ranking liability. Your agency should audit pages with little substantive content, high bounce rates, and poor engagement metrics. These pages may need to be consolidated, expanded, or in some cases, removed from the index altogether. This process is closely tied to your broader content marketing strategy and should align with user intent at every stage.

9. Duplicate Content Detection

Duplicate content confuses crawlers and dilutes link equity. The audit should check for internal duplication (same content across multiple URLs), parameter-based duplication, and near-duplicate pages. Canonical tags should be verified to ensure they point to the correct preferred versions of each page.

10. Backlink Profile and Toxic Link Analysis

A strong backlink profile is one of the most important ranking factors, but toxic or spammy links can trigger algorithmic penalties. Your agency should pull a full backlink report, evaluate domain authority distribution, identify potentially harmful links, and review whether a disavow file needs to be updated or submitted.

11. Internal Linking Structure

Internal links distribute page authority and help Google understand the hierarchy of your site. An audit should identify orphan pages (pages with no internal links pointing to them), over-linked pages, and opportunities to strengthen topical clusters. A well-designed internal linking structure keeps both users and crawlers moving efficiently through your site.

12. Schema Markup and Structured Data

Structured data helps Google understand your content and can earn rich results in search like FAQs, star ratings, and how-to guides. The audit should check whether schema markup is implemented correctly, matches the page content, and passes Google’s Rich Results Test without errors.

13. Local SEO Signals (for Location-Based Businesses)

For businesses targeting local markets, the audit must include a review of Google Business Profile accuracy, NAP (name, address, phone) consistency across directories, and local citation health. A solid local SEO strategy starts with identifying every inconsistency that could suppress your map pack rankings.

14. Analytics and Tracking Verification

You cannot optimise what you cannot measure. The audit should confirm Google Analytics 4 is tracking correctly, that conversion goals are firing, that Search Console is connected and verified, and that no pages are excluded from reporting. Data integrity issues at this level lead to flawed decisions across every channel.

15. Competitor Benchmarking

A great SEO audit does not exist in a vacuum. Your agency should compare your site’s authority, content depth, page speed, and keyword coverage against your top organic competitors. Understanding where rivals outperform you reveals the biggest opportunity gaps and helps prioritise the most impactful areas to address first.

What Happens After the Audit?

A completed audit is only valuable if it leads to a prioritised action plan. Your agency should deliver a structured report that separates quick wins from long-term fixes, assigns effort and impact scores to each finding, and maps each recommendation to specific business goals. If your current agency hands you a list of issues with no context, no prioritisation, and no roadmap, that is a red flag.

At this stage, businesses that are ready to act often choose to move forward with a full digital marketing strategy that covers SEO, content, and paid channels in a coordinated way. The audit findings should directly shape that strategy. 

Final Thoughts

A well-executed SEO audit is the foundation of any successful organic growth strategy. The 15 checks outlined above represent the minimum standard any reputable agency should apply before making recommendations. If your current provider skips these steps or cannot explain what they found and why it matters, it is worth asking harder questions.

Need a transparent, comprehensive SEO audit from a team that treats your goals as their own? Get in touch to find out how we approach every engagement with a structured, results-driven audit process built on data, not guesswork.