llms.txt Checker

Checking by domain validates the file the way a crawler meets it. The checker requests yourdomain.com/llms.txt, then reports the HTTP status, whether the server returns plain text or an HTML page (a common failure: many sites answer a missing file with their 404 page and a 200 status), and whether it redirects to another host. It then checks the structure the llms.txt proposal describes: a # title on the first line, a > one-line summary, ## sections, markdown links to key pages, HTTPS URLs and a sensible length.

It cannot judge whether your descriptions are accurate, so read the file once as a stranger would. If anything fails, rebuild the file with the llms.txt generator, which reads your sitemap and writes this layout, then check it again by URL after you upload it. A pasted draft gets the same structural tests without the server checks, so use paste before you upload and the domain check after.

A clean file is housekeeping, not a growth lever. In our September 2026 check of 1,150 software brands, the half with an llms.txt were not recommended by AI more often than the half without. The data is in does llms.txt work.