What Is an SEO Audit and What Does It Actually Check?
An SEO audit is a structured pass over your site that checks whether search engines can crawl, understand, and rank your pages — and it usually bundles in performance, accessibility, and security checks that affect how your site is experienced and trusted. You run one when you want a prioritized list of fixes rather than a vague sense that "SEO needs work." The catch: an audit tells you what's broken, not what to write or who should link to you.
The categories a scan typically covers
A modern audit isn't just meta tags. Tools like Repolog run 60+ checks in a single headless-browser load, grouped into five areas:
| Category | What gets checked | Why it matters |
|---|---|---|
| SEO / on-page | Titles, meta descriptions, H1–H6 hierarchy, image alt coverage, Open Graph tags, canonical URLs | Tells search engines what each page is about and which URL is authoritative |
| Performance | Core Web Vitals from Lighthouse (FCP, LCP, TBT, CLS, Speed Index) on mobile emulation | Google uses these as ranking signals; slow pages lose both rankings and visitors |
| Accessibility | axe-core against the WCAG 2 rule set: color contrast (AA), alt text, form labels, landmarks, ARIA roles, focus order | Affects real users and increasingly factors into quality assessments |
| Security | 19 read-only checks: HSTS, CSP, X-Frame-Options, HTTPS enforcement, mixed content, exposed .env/.git/wp-config.php, debug endpoints, server version leakage |
Exposed files and missing headers erode trust and can get you flagged |
| AI readiness | 18 checks: robots.txt access for GPTBot, ClaudeBot, PerplexityBot, Google-Extended; JSON-LD structured data; sitemap.xml and llms.txt presence; author/publication metadata; FAQ patterns | Determines whether AI search tools can read and cite your content |
If your goal is only classic Google rankings, the first two rows carry the most weight. The last row matters if you want visibility in AI-generated answers, which is a separate channel with separate rules.
How a scan actually runs
The mechanics are simpler than the output suggests:
- Add your site — enter a domain or import sites you already manage. No install, no code changes, no SDK.
- Run the scan — a real headless browser loads your page and the checks execute against that live render. This is why performance and accessibility results reflect what a browser actually sees, not just raw HTML.
- Read the ranked report — every issue comes with its fix, ordered by impact. A full report typically arrives in about a minute.
The key detail is "live browser load." Checks that run against static HTML miss JavaScript-injected content, layout shifts, and focus-order problems. A headless render catches them.
How to read the results and prioritize
Don't work top-to-bottom through the list. Sort by what blocks indexing or ranking first:
- Crawl/index blockers — robots.txt rules blocking the wrong bots, canonical URLs pointing to the wrong page, noindex tags. Fix these before anything else; nothing downstream matters if the page can't be indexed.
- Core Web Vitals failures — LCP and CLS problems on your highest-traffic templates. Fix the template, not individual pages.
- On-page gaps — missing or duplicate titles, broken heading hierarchy, missing alt text. Fast to fix, moderate ranking impact.
- Security and accessibility — exposed config files and contrast failures. Lower direct ranking impact but real trust and usability costs.
- AI readiness — only worth prioritizing if AI search visibility is a goal for you.
A ranked report does this ordering for you, but you should still sanity-check it against your own traffic data. A "critical" issue on a page nobody visits is less urgent than a "warning" on your top landing page.
One-time audit vs. ongoing monitoring
A single audit is a snapshot. Sites change — you publish, redesign, add scripts, change headers. Two things make an audit useful over time:
- Keyword tracking tied to pages — map each target keyword to the page that should rank for it, then re-scan to grade that page against its keyword. This turns a static report into a feedback loop.
- Search Console integration — surfaces queries you already get impressions for and flags keywords cannibalized across multiple pages, which a one-time crawl can't see.
Repolog's keyword research includes real search volume, difficulty, and CPC per country market, with 20 research runs/month on Starter and 100 on Pro, pooled across the workspace. That's the ongoing layer; the scan is the diagnostic layer.
What an audit can't do
Be clear about the boundary:
- It can't fix content quality. A page can pass every technical check and still not rank because it doesn't answer the query well.
- It can't build backlinks. Off-page authority is outside any on-page scan.
- It can't tell you which keyword to target. It can grade a page against a keyword you've chosen, but the strategic choice is yours.
- It can't guarantee rankings. It removes obstacles; it doesn't create demand.
Treat the audit as a checklist that clears the path, not as the thing that does the walking.
Deciding whether to run one
Run an audit if you've never done one, if you've redesigned or migrated recently, or if rankings dropped without an obvious cause. Repolog offers a free homepage scan — one homepage per day, no signup — which is enough to see whether technical issues are holding you back. If you need ongoing tracking, keyword research, and multi-site management, the paid tier starts with a 7-day free trial. Start with the free scan; only move to a paid plan once you've confirmed there's a backlog of fixes worth tracking over time.