What is Fastmail Bot?
Fastmail Bot is a fetcher operated by Fastmail. You can set up Agent Analytics to see when Fastmail Bot visits your website.
Overview
| Operated By | Fastmail |
| Expected To Follow Robots.txt | No |
| Insights Last Updated | September 15, 2026 |
Do you operate this agent? Contact us to suggest an update.
Category
Expected Behavior
Fastmail Bot usually makes a single request within seconds of a URL being shared, without crawling further. Traffic rises and falls with sharing activity, so a widely circulated link can produce a sharp burst of fetches.
How To Block Fastmail Bot With Robots.txt
Add this rule to your robots.txt file to request that Fastmail Bot not access your website, or use Automatic Robots.txt to request the same of all fetchers at once. You can customize which pages are blocked by swapping out / for a different path.
User-agent: Fastmail Bot # https://knownagents.com/agents/fastmail-bot
Disallow: /Insights for Fastmail Bot
As of September 15, 2026, this data reflects agent visits measured across thousands of websites using Agent Analytics, combined with daily scans of the top 1000 websites and their robots.txt files.
Robots.txt Blocked Percentage
Country of Origin
Robots.txt Blocking Trend
7% of top websites block Fastmail Bot in their robots.txts.
Overall Fetcher Traffic
1.8% of all web traffic came from fetchers.
Frequently Asked Questions
Should I Block Fastmail Bot?
Usually not. Blocking Fastmail Bot may leave shared links without a title or image, making them less inviting to click. If it begins fetching at unexpected volume, try rate limiting before blocking it outright. For context, 7% of the top websites we track currently have robots.txt rules for Fastmail Bot.
Does Fastmail Bot Follow Robots.txt Rules?
No. Fastmail Bot is not expected to follow robots.txt rules, so a disallow rule only communicates your preference. Enforce the block with firewall or server rules, then use Agent Analytics to verify that its requests stop.
Does Fastmail Bot Access Private Content?
No. Fastmail Bot has no credentials and should access only the public URL and assets needed for a preview. It does not continue through the rest of your site.
How Can I Tell if Fastmail Bot Is Visiting My Website?
Agent Analytics tracks Fastmail Bot visits in real time. You can also check your server logs for requests whose user-agent string contains "Fastmail Bot". Look for a page and its preview assets being requested without follow-up navigation. Because Fastmail Bot does not publish a verification method, any client can claim its identity and a log match is only a clue.
Why Is Fastmail Bot Visiting My Website?
Someone shared a link to your page. Fastmail Bot fetched it to build a preview card, and each new share may trigger another request. A spike often means your content is circulating more widely.