What is llms.txt, and why your app site needs one

More and more, people don't open Google to find an app — they ask ChatGPT, Perplexity or Claude "what's a good app for X?" and get a summarised answer. Which raises a question most app sites haven't thought about: when an AI reads your site, does it understand what your app does? A small file called llms.txt is the emerging answer, and it costs almost nothing to add.

What is llms.txt?

llms.txt is a plain markdown file you serve at the root of your site — yoursite.com/llms.txt — that gives large language models a clean, curated summary of what you offer and links to your most important pages. It was proposed in late 2024 by Jeremy Howard (Answer.AI) and has been quietly adopted across a lot of developer-tool and docs sites since.

Think of it as a friendly briefing written for the model: no navigation, no marketing chrome, no cookie banners — just the essentials in a format an LLM can parse in one pass.

robots.txt is for crawlers. sitemap.xml is for search. llms.txt is for LLMs.

Your site probably already ships two machine-readable files:

• robots.txt tells crawlers what they may fetch.
• sitemap.xml lists your URLs for search engines.

Neither helps an AI assistant actually understand your product — they're plumbing, not description. llms.txt fills that gap: a short, human-written summary an LLM can use to represent you accurately.

Why your app's site should have one

When someone asks an assistant about apps in your category, the model assembles an answer from whatever it can read. If your site is heavy with scripts and thin on plain text, you're easy to misdescribe or skip. A clear llms.txt gives the model:

• The one-sentence version of what your app is.
• The features that actually matter, in words.
• Links to your key pages — download, pricing, support.

The upside is asymmetric: it takes minutes to add, and the downside is nil. As AI-mediated discovery grows, being legible to the models is cheap insurance.

What goes in an llms.txt

The format is deliberately simple — a title, a one-line summary in a blockquote, then sections with bullets and links:

# Your App

> A one-line description of what your app does and who it's for.

## What it does

- The core thing it does, in plain language
- A second key capability
- A third

## Links

- [Download](https://yourapp.com): get it on the App Store
- [Pricing](https://yourapp.com/#pricing)
- [Support](https://yourapp.com/contact)

Keep it honest and concrete. The goal is that a model reading only this file could describe your app correctly to someone who asked.

How to add one

Two ways:

1. Write it by hand and serve the file at your site root. Any static host or framework can return a text/plain response at /llms.txt.
2. Let your site generate it. If your app's site is built with Storestand, an llms.txt is generated automatically from your app details and served at the root — alongside your sitemap, structured data and app-ads.txt — so there's nothing to maintain by hand.

Is it an official standard?

Not in the W3C sense — it's a community proposal, not a mandate, and not every model consumes it yet. But adoption is climbing fast, the cost of adding one is a few minutes, and it does no harm if a given assistant ignores it. That's about as easy a bet as SEO offers right now.

The bottom line

Search is splitting into "classic" results and AI-assistant answers, and your app's site should be readable by both. sitemap.xml covers the first; llms.txt covers the second. Add one — or use a builder that ships it for you — and make sure that when an AI describes your app, it gets it right.