---
title: "llms.txt Checker and Validator"
description: "llms.txt checker and validator: fetch or paste an llms.txt, see each error and warning with its line, test up to 20 links and the v2 discovery links. Free."
canonical: "https://browser-use.com/tools/llms-txt-checker"
last_updated: "2026-11-02"
---

# llms.txt Checker and Validator

## Free llms.txt Checker and Validator

Check an llms.txt file against the llmstxt.org format, v2 included. Enter a site or paste the file to see every error and warning by line, and test its links.

## How it works

### Enter a site or paste

A domain fetches /llms.txt. A full URL checks a file at any path, such as /docs/llms.txt.

### Check the format

One H1, a > summary, then H2 sections that list \[name\](url) links. Each finding shows its line.

### Check the links

Optional: up to 20 links are requested to find dead ones and ones that serve HTML instead of Markdown.

### What changed in llms.txt v2?

A file at a subpath, such as /docs/llms.txt, covers the pages under that path. Pages can point to their llms.txt with rel="describedby" and to a Markdown version with rel="alternate" type="text/markdown". The Optional section is still allowed but no longer has a special meaning.

Source: [llmstxt.org](https://llmstxt.org/) · [llmstxt.org: changes in v2](https://llmstxt.org/changes.html)

### Is my file sent anywhere?

Pasted text is checked in this tab and not sent anywhere. For a URL, our server fetches the file (up to 1 MiB), the llms-full.txt next to it, the page it covers and, if you ask, up to 20 links. Nothing is stored.

## Agents read your site. Give yours a browser.

Browser Harness lets Claude Code, Codex or Cursor open pages in your Chrome, logged in as you.

[See Browser Harness](https://browser-use.com/browser-harness)

SourceFetch from URLPaste llms.txtWebsite or llms.txt URLCheck links (up to 20)

CheckLoad example

---

BROWSER USE

- Browser Use Agents: give Browser Use a task and receive completed work. API V4 is current for new integrations.
- Browser Infrastructure: connect your agent or automation to managed browsers through SDK, REST, or CDP. Starts at $0.02/browser-hour.
- Developer tools: Open Source, Browser Harness, SDK, and MCP support the two products above.

[Developer Index](https://browser-use.com/index.md)
[Product Map](https://browser-use.com/llms.txt)
[Full Product Context](https://browser-use.com/llms-full.txt)
[Pricing](https://browser-use.com/pricing.md)
[Cloud Docs](https://docs.browser-use.com/cloud/quickstart)
[Open Source Docs](https://docs.browser-use.com/open-source/introduction)