# llms.txt Adoption Research Report

**9.3% of the top 1,000 domains serve a confirmed llms.txt or llms-full.txt file.** Across the top 10,000, confirmed adoption is **8.3%**. Rankability checked both root-level files using Tranco list V3YPN, dated 2026-09-17. The scan completed September 18, 2026.

## Current adoption

### Top 1,000 domains

| Metric | Result |
|---|---:|
| Confirmed adoption (either file) | 9.3% |
| Confirmed adopters | 93 of 1,000 |
| No file found | 433 |
| Unknown | 474 |
| llms.txt | 93 |
| llms-full.txt | 16 |
| Both files | 16 |

### Top 10,000 domains

| Metric | Result |
|---|---:|
| Confirmed adoption (either file) | 8.3% |
| Confirmed adopters | 830 of 10,000 |
| No file found | 4,959 |
| Unknown | 4,211 |
| llms.txt | 830 |
| llms-full.txt | 119 |
| Both files | 119 |

Confirmed adoption means at least one file was found; each domain counts once. Both-file adopters are included in each individual file count, so those counts should not be added together. Every domain remains in the denominator, including blocked, unreachable and ambiguous results. These are confirmed rates within the ranked sample, not estimates for the entire web.

## Adoption over time

| Observation | Top 1,000 reported adoption | Method |
|---|---:|---|
| June 2025 | 0.3% | Original benchmark |
| June 2026 | 8.7% | Previous scanner |
| September 2026 | 9.3% | Current method |

These are separate published observations, not a continuous monthly series. The June 2026 point is the legacy dataset's scan-month label; that dataset was exported August 23, 2026. The current scan uses a new domain list, stricter content validation, both host variants and nonexistent-URL controls. Changes are not a like-for-like growth calculation. [View the earlier dataset](/research/llms-txt-adoption/2026-09-18/legacy-observations.json).

## Adoption by category

Categories are directional estimates from a curated domain list and domain-name rules. Tranco does not supply categories, and these labels are not manually verified for every site. The top 10,000 breakdown is:

| Category | Adopters | Domains | Rate |
|---|---:|---:|---:|
| Jobs & Careers | 8 | 23 | 34.8% |
| Travel | 8 | 50 | 16.0% |
| Financial Services | 12 | 78 | 15.4% |
| Music Streaming | 6 | 47 | 12.8% |
| Reference | 6 | 61 | 9.8% |
| Other | 685 | 7416 | 9.2% |
| E-commerce | 8 | 108 | 7.4% |
| Technology | 49 | 764 | 6.4% |
| Health & Medical | 2 | 32 | 6.3% |
| Sports | 4 | 70 | 5.7% |
| Social Media | 3 | 56 | 5.4% |
| Food & Recipes | 1 | 20 | 5.0% |
| News & Media | 9 | 184 | 4.9% |
| Education | 9 | 193 | 4.7% |
| Video Streaming | 8 | 193 | 4.1% |
| Gaming | 4 | 103 | 3.9% |
| Publishing | 1 | 29 | 3.4% |
| Entertainment | 2 | 93 | 2.2% |
| Adult | 3 | 177 | 1.7% |
| Government | 2 | 265 | 0.8% |
| Search Engine | 0 | 10 | 0.0% |
| Stock Media & Design | 0 | 12 | 0.0% |
| Real Estate | 0 | 16 | 0.0% |

The visual report highlights the eight highest rates among named categories with at least 30 domains. The full dataset includes every category.

## Examples of confirmed adopters

- [cloudflare.com](https://www.cloudflare.com/llms.txt) — Tranco rank #2
- [github.com](https://github.com/llms.txt) — Tranco rank #29
- [fastly.net](https://www.fastly.com/llms.txt) — Tranco rank #36
- [digicert.com](https://www.digicert.com/llms.txt) — Tranco rank #47
- [wordpress.org](https://wordpress.org/llms.txt) — Tranco rank #48
- [adobe.com](https://www.adobe.com/llms.txt) — Tranco rank #68
- [opera.com](https://www.opera.com/llms.txt) — Tranco rank #91
- [samsung.com](https://www.samsung.com/llms.txt) — Tranco rank #94
- [wordpress.com](https://wordpress.com/llms.txt) — Tranco rank #101
- [unity3d.com](https://unity.com/llms.txt) — Tranco rank #132
- [dropbox.com](https://www.dropbox.com/llms.txt) — Tranco rank #137
- [kaspersky.com](https://www.kaspersky.com/llms.txt) — Tranco rank #140

## Methodology

1. **Fix the sample.** Download the top 10,000 domains from [Tranco list V3YPN](https://tranco-list.eu/list/V3YPN), dated 2026-09-17. The top 1,000 are a subset of the same scan.
2. **Check both files.** Request /llms.txt and /llms-full.txt over HTTPS with an identified Rankability crawler. Follow redirects, try apex and www hosts, and retry transient failures once. A confirmed file ends the search for that path.
3. **Validate the response.** Require HTTP 200, text-compatible content and recognizable Markdown structure. HTML, empty responses and obvious text errors are excluded. Ambiguous content stays unknown. Inspect up to 256 KiB of content, with bounded downloads for large files.
4. **Check apparent positives.** Request a nonexistent text-file URL on each responding host. Catch-all Markdown responses and inconclusive controls are marked unknown instead of confirmed adoption.
5. **Keep uncertainty visible.** Count each confirmed domain once and divide by all sampled domains. “No file found” requires both files to be absent on both host variants. Blocks, timeouts, DNS/TLS errors and inconclusive validation stay unknown.

## Limitations

This is a snapshot of root-level file availability, not a full specification audit or proof that an AI platform uses the file. Documentation subdomains and subpaths are outside the scan unless reached by a redirect. Tranco includes infrastructure domains as well as public websites. Network conditions, redirects and automated validation affect the result. Redirects count as availability; file names do not guarantee complete or distinct content.

The [llms.txt proposal](https://llmstxt.org/) describes Markdown information for agents using a website. A file does not establish search-ranking improvements, AI citations or training permissions.

Earlier results are retained as historical benchmarks. Their different validation rules and ranking lists prevent direct growth claims. This report does not imply an automatic monthly refresh.

## Access the data

- [Download all 10,000 domain verdicts (CSV)](/research/llms-txt-adoption/2026-09-18/domains.csv)
- [Download the study summary (JSON)](/research/llms-txt-adoption/2026-09-18/summary.json)
- [Download the adoption overview chart (PNG)](/research/llms-txt-adoption/2026-09-18/adoption-overview.png)
- [Public study API](/api/llms-adoption)

Dataset license: [Creative Commons Attribution 4.0](https://creativecommons.org/licenses/by/4.0/). Cite Rankability and the scan date when reusing these results.

## Put llms.txt into practice

Read the [llms.txt implementation guide](/blog/llms-txt-best-practices/) or use the [free llms.txt generator](/tools/llms-txt-generator/).