SEO OS proof site
What this site is for
This site exists so that the SEO OS software can run a real, public crawl against pages whose correct results are known in advance. Every page is plain server-delivered HTML. There is no JavaScript, no form, no cookie and no tracking script, so what a crawler downloads is exactly what a reader sees.
What gets tested
The crawl reads robots.txt first, then the XML sitemap, then each listed address. Some addresses are normal pages. Others are planted on purpose: one page is excluded by robots.txt, one page asks not to be indexed, one page names a different page as its canonical version, one address permanently redirects, one address does not exist and one page carries a structured-data block that cannot be parsed. One page is listed in the sitemap but no other page links to it.
How to read the results
A correct crawl reports each of those cases as what it is, never as a success it did not observe. The test guide lists the expected answer for every address in the sitemap.