Technical SEO is the foundation that everything else rests on. You can build the best backlink profile in your niche and publish exceptional content — and watch it fail to rank because a crawl issue prevents Google from indexing it. Site audit tools exist to surface those problems before they cost you traffic.
Ahrefs’ Site Audit tool is one of the most widely used technical SEO crawlers in the industry. It ships as part of every paid Ahrefs plan, covers 140+ technical checks, and includes support for JavaScript rendering and Core Web Vitals.
But is it the best technical SEO checker available in 2026? That depends on what you need it to do. This review covers exactly what Ahrefs Site Audit checks, how to use it, how it compares to alternatives, and an honest verdict on whether it’s worth the cost. For the full platform picture, see our Ahrefs Review 2026.
What Is the Ahrefs Site Audit Tool?
Ahrefs Site Audit is a web crawler that maps and analyzes your entire website for technical and on-page SEO issues. You set it up in your Ahrefs dashboard, configure it with your domain and crawl settings, and it systematically visits every page on your site — checking each one against over 140 SEO criteria.
The output is a prioritized report organized by issue severity (errors, warnings, and notices) with a single Health Score metric (0–100) summarizing your site’s overall technical SEO state.
What makes Ahrefs Site Audit different from a basic crawler:
- JavaScript rendering: Ahrefs can render JavaScript-heavy pages, meaning it can crawl and audit SPAs (single-page applications) and dynamically-loaded content that basic crawlers miss.
- Weekly auto-recrawl: Set it once and Ahrefs will re-audit your site on a schedule, sending alerts when new issues appear or existing ones are resolved.
- Integrated with Site Explorer: When you find a technical issue, you can cross-reference it directly with its organic traffic and backlink data.
- Visual crawl map: An interactive visualization of your site’s internal link structure, making it easy to spot orphan pages, link depth issues, and structural bottlenecks.
What Does Ahrefs Site Audit Check?
The 140+ checks in Ahrefs Site Audit cover five major technical SEO categories:
Crawlability and Indexability
- Pages blocked by robots.txt (intentional or accidental)
- Noindex tags on pages that should be indexed
- Redirect chains and loops (3+ redirects in a chain)
- Broken pages returning 4xx or 5xx status codes
- Canonical tag misconfigurations (conflicting or missing canonicals)
- Pages with excessive crawl depth (more than 3 clicks from the homepage)
- Hreflang implementation errors (for multilingual sites)
On-Page SEO
- Missing, duplicate, or overly long/short title tags
- Missing or duplicate meta descriptions
- Missing H1 tags or multiple H1s per page
- Thin content pages (under-the-threshold word counts)
- Duplicate content across multiple URLs
- Missing or broken canonical tags
- Images without alt text
Performance — Core Web Vitals
Ahrefs Site Audit integrates Core Web Vitals data — Largest Contentful Paint (LCP), First Input Delay (FID), and Cumulative Layout Shift (CLS) — flagging pages that fail the “Good” threshold.
- Slow page speed and its contributing factors
- Large uncompressed images
- Render-blocking JavaScript and CSS
- Missing browser caching headers
Links — Internal and External
- Broken internal links (links to 404 pages within your own site)
- Broken external links (outbound links to dead pages)
- Orphan pages (pages with no internal links pointing to them)
- Redirect links (internal links that pass through a redirect)
- Pages with too few or too many internal links
Structured Data and Social Tags
- Missing or invalid Schema.org markup
- Open Graph tag issues (missing title, description, or image for social sharing)
- Twitter card tag errors
How to Run a Site Audit in Ahrefs (Step-by-Step)
Step 1: Create a new project. In your Ahrefs dashboard, go to Site Audit. Click + New project and enter your domain. Verify ownership via DNS record, HTML file, or Google Search Console integration.
Step 2: Configure crawl settings. Choose your crawl scope: Domain and all subdomains (for full site coverage) or Specific URL paths (for section-by-section audits). Set the crawl speed and decide whether to enable JavaScript rendering.
Step 3: Schedule or run the crawl immediately. You can run immediately or schedule automatic weekly/monthly recrawls.
Step 4: Review the Health Score and top issues. Once the crawl completes, navigate to the Overview tab. Your Health Score is displayed prominently, followed by the number of errors, warnings, and notices.
Step 5: Prioritize by impact. Click into each issue category. Ahrefs shows you the affected URLs, what the issue is, and guidance on how to fix it. Each error type has a “Why and how to fix it” explanation written in plain language.
Step 6: Export and assign fixes. Use the export button to generate a CSV of all affected URLs for each issue type. Share with your developer and track fixes through Ahrefs’ issue progress tracker.
Step 7: Re-crawl after fixes. Once fixes are implemented, trigger a fresh crawl and compare your Health Score before and after.
How to Read Ahrefs Site Audit Results
Understanding the Health Score
The Health Score is calculated as the percentage of internal pages without errors, weighted by issue severity. A score of 90+ is generally strong for an established site. Below 70 typically indicates structural issues that could be suppressing rankings.
Issue Priority Framework
| Level | Description | Action |
|---|---|---|
| Errors | Issues that directly harm crawlability or indexing | Fix immediately |
| Warnings | Issues that may hurt performance or rankings | Fix within the sprint |
| Notices | Informational — good to know, not urgent | Review quarterly |
For most sites, the 80/20 rule applies: fixing the top 5 error categories will address the majority of your technical risk.
Ahrefs Site Audit Limits by Plan
For full plan pricing including annual billing discounts, see our Ahrefs pricing guide.
| Plan | Monthly Price | Pages per Crawl | Projects |
|---|---|---|---|
| Starter | $29/mo | 5,000 pages | 1 |
| Lite | $129/mo | 100,000 pages | 5 |
| Standard | $249/mo | 500,000 pages | 20 |
| Advanced | $449/mo | 1,500,000 pages | 50 |
| Enterprise | Custom | Unlimited | Unlimited |
What this means in practice:
- Small site (under 500 pages): Starter or Lite works fine.
- Mid-size site (1,000–10,000 pages): Lite covers you on crawl volume. If you have multiple client sites, Standard is more practical.
- Large site (100,000+ pages): Standard or Advanced.
- Enterprise/agency: Advanced or Enterprise tier.
Note: Crawl limits are per-crawl, not per-month. If you set weekly recrawls, your effective monthly crawl count is 4x your per-crawl limit.
Ahrefs Site Audit vs. Competitors
| Feature | Ahrefs | Semrush | Screaming Frog | Allable |
|---|---|---|---|---|
| Number of checks | 140+ | 140+ | 150+ | Core issues |
| JavaScript rendering | ✅ | ✅ | ✅ (paid) | ✅ |
| Core Web Vitals | ✅ | ✅ | ✅ | ✅ |
| Auto-scheduled recrawl | ✅ | ✅ | ❌ (manual only) | ✅ |
| Visual crawl map | ✅ | ❌ | ✅ (desktop app) | ❌ |
| Integration with keyword/link data | ✅ Strong | ✅ Strong | ❌ | ✅ |
| Issue explanation (plain language) | ✅ | ✅ | ✅ | ✅ |
| Crawl limits (entry plan) | 5,000 pages | 100,000 pages | 500 URLs (free) | Varies |
| Export options | CSV | CSV, PDF | CSV, Google Sheets | Yes |
| Standalone app | ❌ | ❌ | ✅ (desktop) | ❌ |
| Price (entry level) | $29/mo | $139.95/mo | Free–£259/yr | Affordable |
Ahrefs vs. Semrush Site Audit
Both platforms offer comparable technical depth (140+ checks each), JavaScript rendering, and Core Web Vitals integration. Semrush’s entry-level plan offers a more generous 100,000 pages/month crawl allowance compared to Ahrefs Starter’s 5,000. Ahrefs edges ahead in the visual crawl map and its integration of backlink data into the audit context.
Ahrefs vs. Screaming Frog
Screaming Frog is the desktop crawler of choice for technical SEO specialists. It’s free up to 500 URLs and offers extraordinary depth and customization. But it requires desktop software, has no cloud scheduling, and provides zero backlink or keyword context. For teams that want everything in one cloud-based platform, Ahrefs is considerably more practical.
Ahrefs vs. Allable
Allable’s site audit covers the most impactful technical SEO categories — crawlability, broken links, page speed, on-page issues — in a chat-first interface that doesn’t require technical expertise to interpret. For SMBs and solo marketers, Allable’s guided approach is significantly more accessible — see the full Allable vs Ahrefs comparison. Ahrefs’ depth is better suited for agencies and technical SEOs managing multiple large sites with complex audit workflows.
Is Ahrefs Site Audit Worth It?
For technical SEO professionals and agencies managing multiple client sites — yes, the Ahrefs Site Audit is well worth it. The 140+ checks, JavaScript rendering, visual crawl map, and direct integration with Ahrefs’ keyword and backlink data make it one of the most complete cloud-based audit tools available.
The honest caveats:
- The Starter plan’s 5,000-page limit is a real constraint. For any site with more than a few hundred pages, Lite ($129/month) is effectively the minimum useful tier.
- The data is excellent; the action is on you. Like all Ahrefs tools, the Site Audit surfaces what’s wrong but doesn’t tell you in prioritized plain English what to fix first given your business context.
- For most small sites, a quarterly audit is sufficient. Weekly auto-recrawls on large sites are valuable; running weekly crawls on a 20-page business website adds minimal value.
Frequently Asked Questions
How many SEO issues does Ahrefs Site Audit check?
Ahrefs Site Audit covers 140+ technical and on-page SEO checks organized into five categories: crawlability, on-page SEO, performance (Core Web Vitals), links, and structured data.
Can Ahrefs Site Audit handle JavaScript-heavy sites?
Yes. Ahrefs offers JavaScript rendering as an option when setting up your site audit project. This allows it to crawl single-page applications (React, Vue, Angular) and dynamically-loaded content that wouldn’t be visible to a basic crawler.
How often should I run an Ahrefs site audit?
For most sites, a monthly audit is sufficient. For sites with frequent content publishing (daily or weekly), weekly auto-recrawls are more appropriate. After significant technical changes — server migrations, CMS upgrades, structural URL changes — always run a manual crawl immediately.
What is a good Ahrefs Health Score?
A Health Score above 90 is generally strong. Scores between 70 and 90 indicate fixable issues. Below 70 typically reflects structural problems that warrant prioritized attention. Note that Health Score measures technical completeness, not ranking potential.
Does Ahrefs Site Audit show Core Web Vitals?
Yes. Ahrefs integrates Core Web Vitals data (LCP, FID/INP, CLS) into the Site Audit report, flagging pages that fall below Google’s “Good” thresholds.