# Site audits > Crawl your own site for technical and on-page issues, with Lighthouse on a sample of pages. Source: https://docs.indexzero.site/tools/site-audits An audit crawls the project's site, checks every page against issue types, and runs Lighthouse on a sample. Starting a crawl **costs credits** scaling with page count; reading the results is free. The crawl is asynchronous and takes minutes. ## `run_site_audit` [#run_site_audit] Start a crawl. Returns an `auditId` immediately. Poll `get_audit_status` until it reports `completed`, then read `get_audit_issues`. | Argument | Type | Required | Default | Meaning | | ------------ | ------------------------- | -------- | ---------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | `projectId` | string | yes | | The project must have a domain, or `startUrl` must be given. | | `startUrl` | string, up to 2,048 chars | no | `https://` plus the project domain | Where to start. The crawl stays on the same origin; redirects from the start URL are followed first, so an apex that redirects to `www` anchors on the real origin. | | `maxPages` | integer, 10 to 10,000 | no | 50 | Page budget. A value above the plan's cap is trimmed to the cap rather than rejected, and the response says so. | | `lighthouse` | boolean | no | `true` | Also run Lighthouse on a sample of pages, mobile and desktop. Adds cost and time. | **Returns:** `auditId`, the effective `maxPages`, and `clampedByPlan` when the budget was trimmed. ### How the crawler behaves [#how-the-crawler-behaves] * Identifies as `IndexZero-Audit/1.0`. If your bot protection challenges it, pages are reported as **blocked** rather than broken, and the fix is to allowlist that user agent. * Reads and obeys `robots.txt` for that user agent, and seeds the crawl from the sitemaps it lists. * Stays on the start URL's origin. Private, loopback, and cloud-metadata addresses are refused, and hostnames are resolved to check they do not point at one. * Adapts its concurrency to the site: starts at 10 parallel fetches, backs off when pages are slow, blocked, or erroring, and grows when the site is responding well. * Reads at most 1 MiB of HTML per page with a 15-second timeout. ### Lighthouse sampling [#lighthouse-sampling] The sample is the homepage plus one representative page per URL template, up to 10 URLs, chosen from pages that returned 2xx. Each is run twice, mobile and desktop, so Lighthouse adds up to 20 paid calls. Captured per run: performance, accessibility, best-practices, and SEO scores, plus LCP, CLS, INP, and TTFB. ### Phases [#phases] `discovery`, then `crawling`, then `lighthouse`, then `finalizing`, ending in `completed` or `failed`. `get_audit_status` reports the current phase and pages crawled so far. An audit that fails reports why; the most common cause is a site that takes too long to respond, and the suggested fix is a smaller page limit. ## `get_audit_status` [#get_audit_status] Progress of a crawl: phase, pages crawled, issue count, and whether it finished. **Free.** Do not report on issues until status is `completed`; before that the numbers are partial. | Argument | Type | Required | Meaning | | ----------- | ------ | -------- | ----------------------------------------- | | `projectId` | string | yes | | | `auditId` | string | no | Omit for the project's most recent audit. | ## `get_audit_issues` [#get_audit_issues] The issues a completed audit found, with the URL and detail for each. **Free.** Filter by severity to triage, critical first. Each issue type has a known fix; an agent should ask before changing a site. | Argument | Type | Required | Default | Meaning | | ----------- | -------------------------------- | -------- | ------------ | ------------------------------------------------------ | | `projectId` | string | yes | | | | `auditId` | string | no | latest audit | | | `severity` | `critical`, `warning`, or `info` | no | all | | | `issueType` | one of the issue type ids | no | all | See [Audit issue types](/reference/audit-issue-types). | | `limit` | integer, 1 to 1,000 | no | 200 | | **Returns:** the issue rows and counts by severity. ## `get_audit_pages` [#get_audit_pages] The pages a crawl visited, with status code, title, word count, and H1s. **Free.** Use it to see what was actually reachable and to spot thin or untitled pages. | Argument | Type | Required | Default | | ----------- | ------------------- | -------- | ------------ | | `projectId` | string | yes | | | `auditId` | string | no | latest audit | | `limit` | integer, 1 to 1,000 | no | 100 |