Open Source Technical site audit
Technical audits from our own crawler, with history and fixes your coding agent can run
A free crawler with 117 technical checks, scheduled audits compared run to run, exports for coding agents, and Lighthouse.
- technical checks
- 117
- per Lighthouse run
- $0.05
See it
Site audit
Crawl up to 5,000 pages. You get a health score, the pages that could not be fetched or indexed, and every issue grouped by how much it matters.
Health score, pages crawled and indexable, what was blocked or failed, issue counts and response time, with the sitemap and robots.txt found.
What it does
How the site audit works
OpenSEO has its own crawler. It requests every URL itself, so status codes, redirect chains, headers and response times are exact, and runs 117 technical checks across the site.
Schedule it weekly or monthly and each audit is compared with the last: which issues are new, which you fixed, which titles and pages changed. Export the issues as CSV files, or as one fix brief that Claude, Cursor or any coding agent can work through.
For JavaScript sites and sites behind bot protection, the audit can render pages or fetch blocked ones through YepAPI, only for the pages that need it and up to a cap you set. For page performance, run Lighthouse on mobile or desktop.
What you can do
Site audit features
117 technical checks
The crawler checks your pages for 117 kinds of technical issue: access, redirects, indexability, canonicals, content, duplicates, links, sitemaps, hreflang, structured data and security headers.
Health score
The share of crawled URLs without an error, tracked from audit to audit.
Scheduled audits with history
Run weekly or monthly. Each issue shows what is new, what was fixed and what is no longer crawled, and changed titles, descriptions and status codes are flagged.
Exports for coding agents
Every issue as a CSV of the affected pages and the links behind it, in one zip, plus a fix brief that groups pages by template so an agent fixes the template once.
Search traffic checks
With Search Console connected: pages Google still sends visitors to that redirect, fail, are noindex or canonicalised elsewhere, and pages whose clicks halved.
AI discoverability
Which AI crawlers robots.txt lets in, whether pages read without JavaScript, how fast they answer and whether there is an llms.txt.
Lighthouse, mobile or desktop
Run Lighthouse for either device.
Failed audits, most serious first
Each Lighthouse run rates every failed audit critical, warning or notice by the time it would save, so you fix what matters first.
What it costs
Site audit pricing
Prices at the time of writing, billed by the data provider to your own key. Settings and usage lists every call with its cost.
| Action | Price | |
|---|---|---|
| LighthouseOne run, mobile or desktop | One run, mobile or desktop | $0.05 |
| Site crawlPer crawl, plain HTML | Per crawl, plain HTML | Free |
| JavaScript renderingPer page rendered, optional | Per page rendered, optional | $0.02 |
| Blocked pagesPer page fetched through proxies, optional | Per page fetched through proxies, optional | $0.03 |
In active development. This feature is being built, and parts of what this page describes may not be available yet.
Search data
Start with $5 of free search data
Keyword, ranking and backlink data in OpenSEO comes from YepAPI. Sign up there and new accounts get $5 in free credit, for a limited time. That is enough to try every tool before you spend anything.
- 1
Sign up at YepAPI
New accounts get $5 in free credit, for a limited time.
- 2
Copy your API key
It is on your YepAPI dashboard once you sign in.
- 3
Paste it into OpenSEO
During account setup, or later in Settings. Every tool works from there.
The free credit is YepAPI’s limited-time offer and may end. After it, you pay YepAPI per lookup at its price. OpenSEO lists every call with its cost and a monthly limit caps what you spend. See pricing
Site audit: SEO terms explained
An SEO audit is a review of a whole website’s search performance: its traffic, rankings, keywords, backlinks and competitors, and the opportunities worth acting on first.
Technical SEO is making sure search engines can crawl, render and index your site, covering speed, redirects, canonicals, sitemaps and mobile.
Crawling is how search engines discover pages: automated bots fetch URLs and follow the links on them to find more pages.
A canonical tag is a link element that tells search engines which URL is the main version of a page when duplicates exist.
A redirect chain is when a URL redirects to another URL that redirects again, so it takes two or more hops to reach the final page.
Core Web Vitals are Google’s three metrics for real-world page experience: Largest Contentful Paint, Interaction to Next Paint and Cumulative Layout Shift.