# facebookexternalhit

> The link unfurler: it reads your Open Graph tags when somebody shares your URL on a Meta property.

| field | value |
|---|---|
| operator | Meta |
| category | Link preview fetchers |
| robots.txt token | `facebookexternalhit` |
| user-agent contains | `facebookexternalhit` |
| robots.txt | obeys robots.txt (documented) |
| verify by | no published verification method |
| published IP ranges | none published |
| prefixes mirrored | 0 IPv4 / 0 IPv6 |
| operator docs | https://developers.facebook.com/docs/sharing/webmasters/web-crawlers |
| last reviewed | 2026-09-01 |

## What blocking it costs you

Severe and usually accidental. Your links share as bare grey boxes with no title, image or description across Facebook, Instagram, Messenger and WhatsApp. Almost nobody means to block this.

## Full user-agent string

```
facebookexternalhit/1.1 (+http://www.facebook.com/externalhit_uatext.php)
```

## Block it

```
User-agent: facebookexternalhit
Disallow: /
```

## Allow it

```
User-agent: facebookexternalhit
Allow: /
```

JSON: https://www.pathwren.workers.dev/crawler/facebookexternalhit.json · index: https://www.pathwren.workers.dev/llms.txt