Technical SEO
Core Web Vitals, crawlability, XML sitemaps and mobile-first indexing explained.
Read guideWhat Is an SEO Audit and Why Does Every Site Need One?#
An SEO audit is a systematic evaluation of a website's search engine optimisation performance across technical health, on-page optimisation, content quality, and off-page authority. Regular audits are essential because websites accumulate SEO issues over time: plugins are updated and break things, new content creates internal linking gaps, pages are accidentally noindexed, and competitors improve while you stand still. Most websites have multiple significant SEO issues they are entirely unaware of. An audit surfaces all of these, prioritises them by impact, and gives you a clear action plan to recover or improve rankings.
The Four Pillars of a Complete SEO Audit#
1. Technical SEO Audit
Crawlability, indexation, site speed, Core Web Vitals, HTTPS, redirects, canonicals, mobile-friendliness, structured data, XML sitemap. These foundational issues must be resolved before other optimisations will be effective.
2. On-Page SEO Audit
Title tags, meta descriptions, heading structure, keyword usage, content quality, URL structure, image alt text, internal linking. On-page issues are often the quickest fixes with the fastest ranking impact.
3. Content Audit
Content gap analysis, thin content identification, duplicate content, outdated information, keyword cannibalization, topical coverage. Content audits reveal both problems to fix and opportunities to exploit.
4. Off-Page Audit
Backlink profile quality, toxic link identification, competitor backlink comparison, referring domain growth trend, brand mention analysis. Off-page audits quantify your authority relative to competitors.
Step 1: Technical SEO Audit#
1
Run a Full Site Crawl with Screaming Frog
Screaming Frog SEO Spider (free up to 500 URLs, paid licence for larger sites) crawls your entire website just like Googlebot and reports every technical issue it finds. Key reports to review: Response Codes (find all 4xx and 5xx errors), Redirects (identify chains and loops), Page Titles (find missing, duplicate, or too-long titles), Meta Descriptions (same), H1 (missing or multiple H1s), Images (find missing alt text), Canonicals (verify all canonical tags are correct). Export each report and work through issues by severity.
2
Review Google Search Console Coverage Report
GSC's Index Coverage report (under Indexing → Pages) shows which pages are indexed, which are excluded and why, and which have errors. Common problems: pages accidentally blocked by robots.txt, pages with noindex tags, soft 404 errors (pages that return a 200 status but have no meaningful content), and redirect errors. Each issue type has a specific fix — work through them from most to least impactful.
3
Assess Core Web Vitals
In GSC, the Core Web Vitals report shows how many URLs have "Poor," "Needs Improvement," or "Good" scores for LCP, INP, and CLS. Prioritise fixing "Poor" URLs, especially for high-traffic pages. Use PageSpeed Insights for specific URL-level diagnostics and Lighthouse in Chrome DevTools for detailed technical recommendations. Our Core Web Vitals guide covers every fix in depth.
Step 2: On-Page SEO Audit#
Export your full site crawl from Screaming Frog and audit each of these elements systematically. In the exported spreadsheet, filter and sort to find the worst offenders in each category:
- Missing title tags: Every page needs a unique title tag. Pages with no title get a generic, Google-generated title that is rarely optimal.
- Duplicate title tags: Each page needs a unique title. Duplicates confuse Google about which page to rank for which keyword.
- Title tags over 60 characters: These get truncated in SERPs, cutting off your keyword and call-to-action.
- Missing meta descriptions: Without a meta description, Google auto-generates one, usually unflattering and rarely optimised for CTR.
- Missing H1 tags: Every page should have exactly one H1 containing the primary keyword.
- Multiple H1 tags: Dilutes the heading hierarchy signal to Google and indicates page structure issues.
- Images missing alt text: Poor for both accessibility and image SEO. Export the Images tab from Screaming Frog and fix all missing alt text.
- Thin content pages: Pages under 300 words rarely rank for anything competitive. Identify these and either expand them, consolidate with related pages, or noindex them if they serve no SEO purpose.
Step 3: Content Audit#
Export all your URLs from Google Search Console (Performance report) along with their impressions, clicks, and average position. Import this into a spreadsheet. Categorise every piece of content into one of four groups:
| Category | Criteria | Action |
|---|---|---|
| Keep & Promote | Good rankings, growing traffic, strong engagement | Build links, refresh content annually, add internal links |
| Optimise | Ranking positions 5–20, impressions but low CTR | Rewrite title/meta, improve content depth, add links |
| Consolidate | Multiple pages covering the same keyword (cannibalization) | Merge weaker into stronger, redirect originals |
| Remove or Noindex | Zero traffic, thin content, no strategic value | Delete with 301 to category, or add noindex |
Step 4: Off-Page and Backlink Audit#
Use Ahrefs, SEMrush, or Google Search Console's Links report to audit your backlink profile. Look for: overall referring domain count and trend (growing, flat, or declining?), distribution of Domain Rating across linking domains (a healthy profile has variety, not just low-DR links), anchor text distribution (over-optimised exact-match anchors can trigger Penguin-related ranking suppression), and any obviously spammy or irrelevant linking domains that may warrant disavowal. Compare your referring domain count against the top-ranking competitors for your primary keywords — this gap analysis shows you the link-building work needed to become competitive for specific terms. Full backlink strategy is covered in our Link Building guide.
Prioritising Audit Findings#
A thorough audit will surface dozens — sometimes hundreds — of issues. Prioritise fixes using a simple Impact × Effort matrix. High-impact, low-effort fixes come first: fixing critical indexation errors, resolving duplicate title tags, adding missing meta descriptions, and rewriting the five pages with the highest impressions but lowest CTR. High-impact, high-effort items (site speed overhauls, content consolidation projects) go into a planned project roadmap. Low-impact items go to a future backlog. Use our SEO Checklist to systematically work through every item once your priorities are set.