What is facebookexternalhit?
facebookexternalhit is Meta's web crawler that fetches content from apps or websites shared on Facebook, Instagram, or Messenger to gather, cache, and display information like titles, descriptions, and thumbnail images. Agent Analytics can track when it visits your website.
Category
Expected Behavior
facebookexternalhit shows up within seconds of someone sharing one of your URLs, grabs the title, description, and preview image, and leaves. Expect one hit per share, no link following, and volume that tracks how much your content circulates. A widely shared link can mean thousands of fetches in an hour.
Overview
| Operated By | Meta |
| Expected To Follow Robots.txt | No |
| Insights Last Updated | July 6, 2026 |
Robots.txt Blocked Percentage
Country of Origin
Robots.txt Blocking Trend
As of July 6, 2026, 10% of top websites block facebookexternalhit in their robots.txt files.
Overall Fetcher Traffic
As of July 6, 2026, 3.8% of all web traffic came from fetchers.
Top Visited Website Categories
This data reflects agent visits measured across thousands of websites using Agent Analytics, combined with daily scans of the world's top 1000 websites and their robots.txt files.
facebookexternalhit's User Agent
| User Agent | facebookexternalhit/1.1 (+http://www.facebook.com/externalhit_uatext.php) |
Access other known user agents and IP addresses using the Enterprise API.
How To Block facebookexternalhit
Add this rule to your robots.txt file to request that facebookexternalhit not access your website. You can customize which pages are blocked by swapping out / for a different path.
User-agent: facebookexternalhit # https://knownagents.com/agents/facebookexternalhit
Disallow: /Frequently Asked Questions
Should I Block facebookexternalhit?
No. facebookexternalhit builds the link preview that appears when someone shares your page in a chat or social feed. Blocking it turns those shares into bare links with no title or image, which fewer people click. Its traffic normally follows sharing activity rather than a crawl schedule, so if it ever starts crawling at volume, rate limit it instead of blocking it. For comparison, 10% of the top websites we track already have robots.txt rules for facebookexternalhit.
Does facebookexternalhit Respect Robots.txt?
No. facebookexternalhit is not expected to honor robots.txt, so a disallow rule only states your preference. Enforce the block with firewall or server rules, then confirm in Agent Analytics that its requests actually stop.
Does facebookexternalhit Access Private Content?
It cannot. facebookexternalhit loads only the exact URL someone shared, reads the title, description, and preview image, and leaves. It has no credentials and does not follow links to other pages.
Why Is facebookexternalhit Visiting My Website?
Someone shared a link to your page. facebookexternalhit fetched it once to build the preview card, and every new share can trigger another fetch, so spikes mean your content is spreading.
How Can I Tell if facebookexternalhit Is Visiting My Website?
Agent Analytics tracks facebookexternalhit visits in real time alongside every other known AI agent, crawler, and scraper. You can also check your server logs for requests whose user agent string contains "facebookexternalhit". Look for hits on single pages moments after someone shares a link, with no crawling afterward. Keep in mind that facebookexternalhit doesn't publish a verification method, so any client can claim its user agent string and a log match is a hint rather than proof.