What is Fastmail Bot?
Fastmail Bot is a fetcher operated by Fastmail. Agent Analytics can track when it visits your website.
Category
Expected Behavior
Fastmail Bot 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 | Fastmail |
| 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, 0% of top websites block Fastmail Bot in their robots.txt files.
Overall Fetcher Traffic
As of July 6, 2026, 3.8% of all web traffic came from fetchers.
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.
How To Block Fastmail Bot
Add this rule to your robots.txt file to request that Fastmail Bot not access your website. 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: /Frequently Asked Questions
Should I Block Fastmail Bot?
No. Fastmail Bot 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. Almost none of the top websites we track have robots.txt rules for Fastmail Bot right now.
Does Fastmail Bot Respect Robots.txt?
No. Fastmail Bot 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 Fastmail Bot Access Private Content?
It cannot. Fastmail Bot 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 Fastmail Bot Visiting My Website?
Someone shared a link to your page. Fastmail Bot 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 Fastmail Bot Is Visiting My Website?
Agent Analytics tracks Fastmail Bot 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 "Fastmail Bot". Look for hits on single pages moments after someone shares a link, with no crawling afterward. Keep in mind that Fastmail Bot 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.