How to Add a Sender to Your Fastmail Contacts

How to Add a Sender to Your Contacts in Fastmail

by Heinz Tschabitscher | Nov 6, 2025 | Email Tips and Resources

Want to do more than hoard a mountain of archived emails? How about turning those messages into a curated personal address book? Find out here how to add a sender to your contacts in Fastmail on both desktop and mobile devices.

First, Fast as Water in a Bowl of Mountains

Lake Maracaibo in Venezuela is a vast bowl of water cradled by mountains on every side. During the day, the surface warms in the Andean sun. At night, warm, moist air rising from the lake meets cool, dry air flowing down from the peaks — and powerful thunderstorms gather almost like clockwork.

If you want to capture lightning on film, one night at Lake Maracaibo will usually do, maybe two. To capture an email’s sender in your contacts, you don’t even have to wait that long — it’s practically fast as lightning:

How to Add a Sender to Your Contacts in Fastmail

Using the People Sidebar (Desktop App and Browser)

Time needed: 2 minutes

To add a sender to your address book in Fastmail:

  1. Open an email from the sender you want to add to your contacts.

  2. Open People in the sidebar.

    Here’s how: Click Show sidebar, then go to the People tab.
    Fastmail keyboard shortcut: You can press Command Shift I (Mac) or Ctrl Shift I (Windows and Linux) to toggle display of the sidebar.

  3. Select In Conversation from the top drop-down menu under People.

  4. Click the sender’s name and email address under Sender.

    Select the sender in the Fastmail “People” sidebar under “In conversation”

  5. Now click Add to contacts.

    No “Add to contacts”: If the address is already in your Fastmail address book, you will see Edit instead.
    Select “Add to contacts“ to create an address book entry for a sender in Fastmail

  6. Optional: Edit the contact’s details.

    Here’s how: Click Edit, make the desired changes and click Save.

Add a Sender As Is to Contacts Using a Context Menu (Mobile App and Browser)

To add a sender to your Fastmail contacts quickly as is:

  1. Open an email from the sender.
  2. Click the avatar or the sender’s name in the message header area.
    Here’s where: The sender name and avatar appear before the sender’s email address (which is enclosed in angled parentheses).
    No sender name: If the sender has just used the email address, Fastmail will display the user name as the sender’s “name.”
  3. Select Add to contacts in the context menu that has appeared.
    Already a contact: If the sender is already in your Fastmail address book, you will see View Contact instead.
    Select “Add to contacts” to create an address book entry for a sender in Fastmail on a mobile device

How to Add a Sender to Your Contacts in Fastmail: FAQ

Can I directly add a sender’s email address to an existing contact?

No.

Adding a sender will always create a new entry in your Fastmail contacts.

You can add the email address to the existing contact, of course:

  1. Click the sender’s name (or username) in the email header area.
  2. Select Copy email address from the context menu.
  3. Go to Fastmail People in the sidebar.
  4. Select All contacts.
  5. Now click the existing contact.
  6. Click Edit.
  7. Choose a label for blank address field under Email.
  8. Paste the address over email@example.com.
  9. Click Save.

As an alternative, you can add then new email address, then merge the entries in Fastmail Contacts.

(Tested with Fastmail in a desktop browser; first published November 2025)

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