Site audit

The site audit crawls your site the way a search engine does: it reads robots.txt, starts from your sitemaps, stays on your origin, and checks every page it reaches against 27 issue types, each with an explanation and a fix. Your agent can start it, wait for it and read the results over MCP.

Start freeRead the docs
Plan
Every plan. Pages per audit: Free 50, Starter 1,000, Pro 5,000, Scale 10,000.
Cost
Only the Lighthouse sample costs credits: up to 20 runs, whatever the page count. The crawl itself is free, so an audit with Lighthouse switched off spends nothing. Reading results is free.
Checks
27 issue types in three severities
Crawler
Identifies as IndexZero-Audit/1.0

MCP tools: run_site_audit, get_audit_status, get_audit_issues, get_audit_pages

What it checks

  • Critical (4): crawler was blocked, server error (5xx), broken internal link, missing title tag.
  • Warning (14): page returns an error (4xx), duplicate title, duplicate meta description, duplicate page content, missing meta description, missing H1 heading, multiple H1 headings, redirect chain, redirect loop, conflicting canonical signals, thin content, images missing alt text, orphan page, page has no outgoing links.
  • Info (9): title too long, title too short, meta description too long, meta description too short, heading levels skip, slow server response, page is noindex, canonicalized to another URL, page is deep in the site structure.

How the crawler behaves

  • It identifies as IndexZero-Audit/1.0, reads and obeys robots.txt for that user agent, and seeds the crawl from the sitemaps robots.txt lists.
  • It stays on the start URL's origin, and refuses private, loopback and cloud-metadata addresses.
  • It adapts to the site: it starts at 10 parallel fetches, backs off when pages are slow, blocked or erroring, and speeds up when the site responds well.
  • It reads up to 1 MiB of HTML per page, with a 15-second timeout.
  • When bot protection challenges it, the page is reported as blocked rather than broken, and the fix is to allowlist the user agent.

Lighthouse on a sample

The audit also runs Lighthouse on up to 10 pages, the homepage plus one page per URL template, on mobile and desktop. Each run records performance, accessibility, best-practices and SEO scores, with LCP, CLS, INP and TTFB.

Lighthouse is a lab test, one page load under fixed conditions, so its numbers can differ from what real visitors experience. Use it to find slow templates.

Reading the results

In the dashboard, a running audit shows its phase, the pages crawled so far and a live feed of URLs. A finished one shows issue counts by severity, then each issue type with its explanation, its fix and the affected URLs. Below that are the crawled pages and the Lighthouse table. Everything exports to CSV.

Over MCP, an agent reads the same results with get_audit_issues, filtered by severity or issue type, and get_audit_pages. A coding agent such as Claude Code or Cursor can then make the fixes in your codebase, and start a second audit to confirm them.

Frequently asked questions

How many pages can one audit crawl?
It depends on the plan: Free 50, Starter 1,000, Pro 5,000, Scale 10,000. A bigger budget is trimmed to the plan's cap rather than refused.
Can I audit a site behind Cloudflare?
Yes, once the crawler is let through. Add a WAF custom rule that skips bot protection when the user agent contains IndexZero-Audit, then run the audit again. Until then, challenged pages are reported as blocked.
Do audits run on a schedule?
No. You or your agent start each audit. A re-crawl after each release, or once a month, catches regressions early.
GuideHow to run a site audit with an AI agentHave an agent crawl your site, wait for the crawl to finish, triage the issues by severity, fix them in your codebase, and re-crawl to confirm.Free tool, no accountSEO checkerRun the on-page checks from IndexZero's site audit against one URL: titles, meta descriptions, headings, canonicals, indexability, redirects and response time.

Other features

Deciding whether IndexZero fits? Who it's for, and when another tool is the better choice.