Audit a site

OpenSEO crawls your site with its own crawler, so a normal audit costs nothing. It checks every page it reaches against 59 kinds of problem (4 critical, 32 warnings and 23 notices) and sums them up as a health score.

Run an audit

1. Start it

   Open Site audit and click New audit. The start URL defaults to your project's website. Choose how many pages to crawl, up to 5,000. Then click Start audit.

2. Let it crawl

   The crawler is polite: two requests at a time, at least half a second apart, and it follows robots.txt, including its Crawl-delay (up to 10 seconds). It finds pages through links and through your XML sitemaps. Progress updates every 10 pages; you can leave the page or cancel.

3. Only if your site needs it: render JavaScript

   Sites that build their content in the browser look empty to a plain crawler, and the audit flags them with "Content needs JavaScript rendering". For those, tick Render JavaScript. Each page is then rendered through YepAPI at $0.02, up to 500 pages, and you confirm the maximum before it starts.

Read the results

The top of the audit shows the health score, pages crawled, how many are indexable, how many were blocked or failed, the issue counts by severity, and whether a robots.txt and sitemaps were found.

If the crawl stopped at your page limit, a note says so. Findings that compare pages with each other (duplicates, orphan pages, broken links) are then partial; run it again with a higher limit to cover the whole site.

Work through the issues

The Issues tab groups findings by severity, then by type. Open a group to see what it means, how to fix it, and every affected URL with the detail for that page (which link is broken, which canonical is wrong and so on). Start with critical issues: they stop pages from being crawled, indexed or shown. Issues CSV exports everything for a spreadsheet or a ticket.

Look at single pages

The Pages tab lists every URL with its status, indexability, word count, depth, response time and issue count. Sort by most issues or slowest response, filter by URL, and click a page for everything recorded about it: why it is or is not indexable, its redirect chain, title, description, headings, structured data and its issues.

The exact formula and every check are listed in Site audit checks.

Test a page with Lighthouse

Below the audit list, the Lighthouse card tests one URL on mobile or desktop ($0.05; a repeat within the hour is free). It shows the four Lighthouse scores, the Core Web Vitals (largest contentful paint, layout shift, total blocking time, first contentful paint, speed index) graded good, needs work or poor, and every failed audit with a severity, most serious first:

• Critical: fixing it would save 300 ms or more, or the audit scores under 50.
• Warning: it would save 100 ms or more, or scores under 90.
• Notice: anything else that failed.

Within a severity, the biggest saving comes first.