Free SEO tool

llms.txt Checker

This llms.txt checker requests /llms.txt at the root of a website and reports whether the file exists, its HTTP status, any redirect, its content type and its size. It then checks the Markdown structure proposed at llmstxt.org: an H1 title first, an optional blockquote summary and H2 sections that list links.

How to Use the llms.txt Validator

Enter any URL of the website and submit it: the validator requests /llms.txt once, at the same scheme, host and port, and checks what comes back.

Enter a URL of the website, including https://. Any page works, because only the origin is used.
Select Submit. The checker requests /llms.txt at that origin and follows any redirects.
Read the file summary: whether the file was found, the HTTP status, the content type and the size.
Read the structure checks: the H1 title, the blockquote summary, headings before the first H2 and the link lists.
Open the links of each H2 section to confirm they point to the pages you meant, then fix the file and check it again.

llms.txt Format the Checker Looks For

The checker compares the file with the format proposed at llmstxt.org, where an H1 title is the only required section and everything else is optional but ordered.

Found, Missing or Refused

Found means /llms.txt answered with a 2xx status and a text file. Missing means a 404 or 410 status, so the site has no llms.txt at its root. Refused means the server answered 401, 403 or 429, or showed a bot challenge; any other status is reported as an error status.

HTML Page Instead of a File

Some sites answer every path with the same web page, so /llms.txt returns status 200 with HTML. The checker reports this when the content type is text/html or the body starts with an HTML document, and it does not check the structure of that page.

Content Type, Size and Encoding

The proposal does not require a content type, so text/plain and text/markdown pass while a missing or other type is a warning to review. A file larger than 1,048,576 bytes is cut and only its first part is checked. A file that is not valid UTF-8 is flagged as well.

H1 Title

The H1 with the name of the project or site is the only required section, and it comes first, after an optional byte-order mark. The check fails when the first line with content is anything else and shows that line. A second H1 later in the file is a warning.

Blockquote Summary

A blockquote directly after the title, lines starting with >, holds a short summary of the project. It is optional, so a file without one gets an information note, not a failure.

Headings Before the First H2

Between the summary and the first H2, the proposal allows paragraphs, lists and other Markdown of any type except headings. The checker lists every other heading it finds there, with its line number.

H2 Sections and Link Lists

Each H2 section holds a file list: list items that start with a [name](url) link, optionally followed by a colon and notes. The checker counts the links of each section, lists items without such a link with their line numbers and warns about sections without any link. A section named Optional, for links an agent can skip, is reported as present or absent.

llms.txt Example

A minimal file that passes every check starts with the line # Example Docs, then the line > Documentation of the Example library. After a blank line comes ## Docs, followed by the list item - [Quick start](https://example.com/start.md): install and first steps.

What Is llms.txt?

llms.txt is a proposed convention, published at llmstxt.org in September 2024, for a Markdown file that gives language models a short guide to a website and links to its most useful pages. It is a proposal, not a standard of a search engine or a standards body.

Where the llms.txt File Lives

The proposal places the file at the root path /llms.txt of a website, or at a subpath such as /docs/llms.txt that covers the URLs under it. This checker requests only the root file of the origin you enter: the same scheme, host and port.

llms.txt and Search Engines

No search engine documents using llms.txt for crawling, indexing or ranking. Google's documentation on AI features in Search says that no new machine readable files or AI text files are needed to appear in them. Keep robots.txt and sitemaps for search engines and treat llms.txt as an optional guide for language model tools.

Frequently Asked Questions About llms.txt

How Do I Verify My llms.txt File?

Enter any URL of your site in the checker above. It requests /llms.txt at that origin, shows the status and content type the server sends, and checks the title, summary and link sections against the format at llmstxt.org. Fix any failure or warning, then run the check again.

Where Do I Put the llms.txt File?

Put it at the root of the site, so that it answers at /llms.txt on your domain with a 200 status. The proposal also allows a file in a subpath, such as /docs/llms.txt, for the URLs under that path, but this checker reads only the root file.

Does llms.txt Work for SEO?

No search engine documents llms.txt as a signal for crawling, indexing or ranking, and Google's documentation on AI features says no AI text files are needed to appear in AI Overviews or AI Mode. The file is a proposal for language model tools and agents that choose to read it. A missing llms.txt does not change the score of a full audit.

llms.txt vs Sitemap: What Is the Difference?

An XML sitemap lists the URLs a search engine may crawl, in a format search engines document. llms.txt is a Markdown file written for language models: a title, a short summary and curated links, which the proposal suggests may point to Markdown versions of pages. A site can publish both, and llms.txt does not replace the sitemap.

Why Does the Checker Say My llms.txt Is an HTML Page?

Your server answered /llms.txt with a web page instead of a text file, usually because the site sends every unknown path to its application or to a not found page with status 200. Create the file at the root of the site, or add a route that serves it as text/plain or text/markdown. Then check the URL again.