Fastmail Read Receipts: Does Fastmail Track Your Email?

Fastmail read receipts work in one direction only: you can request one, but Fastmail's apps never send one back. The bigger question for anyone paying for Fastmail to get away from Gmail is the tracking pixel. Can a sender still tell you opened their newsletter? Mostly yes. Fastmail's image proxy hides your IP address and browser, but it fetches the image the moment you open the message, and it names itself as Fastmail while doing so.

Key Takeaways

• Fastmail's help center says its interface "does not respond to requests for read receipts," so a sender who asks a Fastmail user for one gets nothing back.
• Fastmail has proxied remote images since September 16, 2014, hiding your IP address, but its bots page says images are fetched "when a user opens an email," so senders still learn when you opened.
• Fastmail documents no tracking link cleaning: a search of its help center for "utm" returned zero articles, and its 2014 proxy announcement says "The original email is never modified."
• Fastmail's privacy policy contains no instance of the words "pixel," "beacon" or "track," and its vendor list names Mailchimp for "Email marketing and automation," with every newsletter sent to a single use address.
• Of Fastmail, Gmail, Proton Mail and HEY, only Proton documents fetching images at delivery rather than at open, which hides when you read.

Does Fastmail Have Read Receipts?

Fastmail lets you request read receipts but never sends them. Its read receipts help page explains the sending side: in the composer, click More and select Request read receipt, which is "usually only supported if your recipients are using Outlook or Thunderbird."

The receiving side is one sentence long: "The Fastmail interface does not respond to requests for read receipts, but will display receipts others have sent to you." The help page lists no setting that changes this. A marketer who adds a receipt request to a message bound for your Fastmail inbox learns nothing from it.

These receipts follow the Message Disposition Notification standard, and RFC 8098 says "it is strongly recommended that the user agent obtain the user's consent before sending an MDN." Fastmail never sends one. Google's help page says read receipts "don't work with personal Gmail (@gmail.com) accounts." Our explainer on how Gmail read receipts work covers the work account exception.

Does Fastmail Block Tracking Pixels?

Fastmail can block every remote image until you ask for it, and it proxies the images you do load, but by its own account it doesn't try to pick out trackers. Its remote images help page offers three choices under Settings, Mail preferences, Reading:

• Show remote images: everything loads automatically.
• Show remote images from senders in my contacts, otherwise ask: contacts load, strangers wait.
• Always ask before showing remote images: nothing loads until you click Load images.

Messages in Spam get no choice: "Remote images are always blocked for messages in the Spam folder." Fastmail's reasoning for blocking everything rather than only trackers comes from a 2021 post, Fastmail Keeps You Safe From Spy Pixels: "We block all remote images rather than guess at which particular ones might be used for spying, because any image can be used as a spy pixel."

Which option does a new account start on? Fastmail's help pages don't say. The same 2021 post claims "Fastmail has blocked spy pixels by default for years," yet in a 2019 Hacker News thread one Fastmail customer asked "why isn't it turned on for new accounts?" while another replied that Fastmail "does block (well, decline to load) remote images by default." Check your own setting.

Once you load images, the proxy takes over. Fastmail launched it on September 16, 2014, and the help page now says the image host "won't know your IP address or browser." The same 2014 post carries an honest correction, added after launch: the image server "may still be able to determine who the request came (ie email address validation) if the image URL has some kind of tracking data in it." The 2021 post explains why that matters: "Some senders take an additional step and they create a unique link for each recipient to the image they use to track."

How Does Fastmail's Image Proxy Work Under the Hood?

Fastmail rewrites each image address to a signed URL on its own domain and fetches the original when you open the message. Its bots policy describes the trigger: "When a user opens an email with links to embedded images, we load and proxy those images via our servers on the user's behalf." It also publishes the user agent the proxy sends:

Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/118.0.5993.117 Safari/537.36 FastmailUA/1.0

Fastmail promises that every such string will "always contain the string 'FastmailUA'." So the sender's log shows a Fastmail server address, a user agent naming Fastmail, and the second the image was requested. Pair that with a pixel URL unique to you and the sender knows you opened the email, and when. Your IP address, device and location stay hidden.

The proxy is open source. Fastmail's hopscotch repository, written in Perl and last pushed November 26, 2024, describes "a tiny, high-performance HTTP image proxy" whose URLs look like http://hopscotch/<digest>/<hexurl>, where the digest is "the SHA256 HMAC digest generated from the unescaped image URL and a secret key." Without the secret key, nobody else can mint a valid proxy URL.

Is that what runs in production? A 2018 fanboy-adblock report shows a real Fastmail image URL: www.fastmailusercontent.com/proxy/<64 hex characters>/8647470737a3f2f2.... We decoded that second segment: it is "https://" in the low nibble first hex that hopscotch's sample code produces with unpack("h*", $URL). The format matches, though we can't confirm that code serves your mail today.

Does Fastmail Clean Tracking Links?

No, Fastmail has no documented feature that strips tracking parameters or unwraps click redirects. A search of the Fastmail help center for "utm" returned zero articles on October 2, 2026, and the 2014 proxy post states the design principle plainly: "The original email is never modified." Tracked links reach the sender's click server as written, and because your browser visits them directly, your real IP address goes along.

That's a real gap next to Proton, which has cleaned known tracking parameters on its web app since July 2023, as we documented in our Proton Mail tracking investigation. Our guide to blocking click tracking in Gmail explains how those redirects log you before forwarding you on.

Does Fastmail Itself Track You?

We found no sign that Fastmail tracks your email for advertising, though it does run product analytics. We ran exact string checks on October 2, 2026 against the current Fastmail privacy policy: "pixel" appears 0 times, "beacon" 0 times and "track" 0 times; the only matches for "open" sit in the site menu and footer. The cookies policy has neither "pixel" nor "beacon." What the policy does say:

• "We do not use profiling for personalized content or ads."
• Its latest change note reads "Confirming that we do not use customer data to train AI."
• Fastmail uses data to "Understand how our services are used through analytics," and its subprocessor list names Posthog for "Analytics in order to improve user experience" and Sentry for "Application logging."

Fastmail's privacy help page says it isn't HIPAA compliant because HIPAA requires "mandated end-to-end encryption, which we do not provide." Fastmail's safeguard is a policy, "We use your data only for the purposes you have paid for"; Proton's is encryption that keeps stored message bodies unreadable to Proton itself. Those are different guarantees.

Do Fastmail's Own Newsletters Contain Tracking Pixels?

We couldn't confirm either way. Fastmail uses an outside partner for newsletters and shields your real address from it, and its subprocessor list names Mailchimp for "Email marketing and automation." The privacy help page says "we generate a single use address for every Fastmail newsletter recipient, ensuring that our newsletter partner receives no information about you." Newsletters go out "4-6 times per year," and the newsletter help page adds that "By default, most Fastmail users will be automatically opted in."

Mailchimp turns open tracking on for senders by default, as we covered in does Mailchimp track email opens. If that partner is Mailchimp with open tracking on, a pixel would tell Mailchimp that a throwaway address opened the newsletter, not who you are. The opt out lives under the Help icon, What's New, Send me email updates.

Our DNS checks, run October 2, 2026, found no tracking host of Fastmail's own:

• Mail routing: fastmail.com and topicbox.com point MX at in1-smtp and in2-smtp.messagingengine.com, and their SPF includes only spf.messagingengine.com: three Fastmail address blocks, no outside email service.
• DKIM: fastmail.com publishes Fastmail's own fm1, fm2, fm3 and mesmtp selectors. Nothing answers at k2, the selector Mailchimp's domain authentication guide uses, or at k3. A nonsense selector returned NXDOMAIN, so the absence is real.
• Tracking hostnames: fastmail.com runs a wildcard. A nonsense subdomain resolved to 103.168.172.52 and 103.168.172.37, and track, click, pixel, open, links, news and 19 other candidates returned the same pair, so resolving proves nothing there. None carried a CNAME to an email platform.
• Certificates: CertSpotter listed 13 current names for fastmail.com, from api and caldav to join and www, and none looked like a tracking host.

One caveat: Mailchimp serves its pixels from its own domains, so a clean fastmail.com zone can't rule them out.

What About Masked Email and Topicbox?

Masked Email keeps your real address from each company but doesn't stop pixels, and Topicbox documents no open tracking. Fastmail's Masked Email page describes addresses "formatted as random words plus a random number, e.g. dog.food3495@domain.tld," one per service, which you can disable when the mail turns unwanted. A pixel in mail to a masked address still fires when you load it; it just reports against an address only one company has.

Topicbox, Fastmail's group email product, shares Fastmail's MX hosts, SPF include and DKIM selectors. A search of the Topicbox help center for "tracking" returned two articles, on two step verification and login trouble, and "analytics" returned none.

Fastmail vs Gmail, Proton and HEY: Who Hides Your Opens?

All four proxy images; only Proton documents hiding the moment you open. Proton's tracker protection page says "We also pre-load other remote images on your behalf," and its 2022 post says images load "as soon as an email is delivered rather than when you open it." HEY's image proxy page says it fetches "When users view emails containing external images," and its tracker page claims it will "catch 98% of all the tracking." Gmail's image help page concedes senders "may know whether you've opened" a message.

Proton's preloading makes every message look opened on arrival, so its open data is noise. Fastmail's proxy records a real open at the real time. Your identity is masked; your behavior is not. Apple's Mail app takes Proton's route, as we explain in Apple Mail Privacy Protection and fake opens.

What This Means for Your Gmail Inbox

Fastmail's protection follows the app you read in, not the address mail was sent to. The 2021 post says: "If you use a third party client or program to read your mail, we can't intercept these images." Read Fastmail over IMAP in Thunderbird and Thunderbird's rules apply; it blocks remote content by default, as our Thunderbird read receipts investigation found.

The same goes for a Gmail account you keep for old logins. Anything you open at mail.google.com gets Gmail's treatment, and Google's proxy still confirms the first open and its timing. We explain what gets through in the tracking pixel that learned to dodge Gmail.

How Do You Lock Down Fastmail and Block Tracking Elsewhere?

Change one setting, then cover the gaps. Per Fastmail's mailbox settings page:

1. Set Remote images to Always ask under Settings, Mail preferences, Reading. The proxy alone won't stop a pixel from firing.
2. Click Load images only when you need them. Each click tells the sender you opened, even through the proxy.
3. Consider plain text. The View messages in option shows mail without images.
4. Skip tracked links. Fastmail leaves them alone, so type the store's address instead.
5. Hand out Masked Email addresses to every shop and newsletter, and disable any that start leaking.

For mail you read outside Fastmail, these are the browser options, checked on October 2, 2026:

• Trocker (10,000 users, version 3.4.1, updated July 10, 2026) says it "keeps you safe in all webmails by blocking known trackers in the background," with extra features in Gmail, Yahoo and Outlook.com.
• PixelBlock (40,000 users, last updated December 2, 2025) is "a Gmail extension that blocks people from tracking when you open their emails."
• Ugly Email is gone; its Chrome Web Store listing is empty.
• Gblock works in Gmail on desktop Chrome only. Its blocklist updates itself and covers Mailchimp's list-manage.com/track pixel; it flags unknown images of 150 bytes or less and strips tracking parameters from links.

Plainly: Gblock does nothing inside Fastmail, its apps or a desktop client. If all your mail lives in Fastmail, Always ask covers most of it. Gblock fits readers who kept Gmail next to Fastmail, or who are weighing a switch only to escape pixels. More in how to block email tracking in Gmail, our roundup of email tracker Chrome extensions, and the best private email providers.

What We Could Not Verify

We did not open a Fastmail account or send it tracked mail, so the new account default and whether the proxy caches images stay unconfirmed. Fastmail's web client is closed source. Our probes of www.fastmailusercontent.com were inconclusive: /proxy/ and a nonsense path returned the same nginx 404, consistent with hopscotch's "returns 404 for all errors." We never received a Fastmail newsletter, and Topicbox list mail went untested.