FMail3

Fastmail and FMail3: Bridging the Gap on macOS

What Is FMail3?

FMail3 is a native macOS app that wraps Fastmail's web interface in a proper Mac shell. You get the full Fastmail experience — every feature, every update — with the native window management, notifications, and system integrations you expect from a Mac app.
No Electron. No compromises. Just Fastmail, done right.

Native Mac Windows And Tabs

Open multiple Fastmail views as real macOS tabs. Switch between them with Command+Tab (or Command+Number), exactly like Safari or any other Mac browser. Your tabs — and their scroll position, navigation history, and open conversations — are saved and restored automatically every time you launch.

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Features

Everything you need

🪟

Native Windows & Tabs

Multiple macOS windows and tabs with automatic save and restore on launch. Use ⌘+number to jump to a specific tab.

🖱️

Smart Click Modifiers

⌘+click opens a new tab, ⇧⌘+click focuses it, ⌥⌘+click opens a new window, ⇧⌥⌘+click opens and focuses a new window.

🔔

Real-Time Inbox Count

Your dock icon and menu bar always show your real inbox count, updated in real time via Fastmail's JMAP push connection. No polling delay. No manual refresh.

💬

Native Notifications

New email notifications arrive natively through macOS — with a direct delete option, no open window required.

✉️

Default Email Client

Register FMail3 as your default email client and every mailto: link on the web opens a pre-filled Fastmail compose window.

✍️

Compose-in-Window Mode

Prefer to write email without your inbox staring back at you? Enable compose-in-window mode for a clean, focused drafting experience.

🎭

Masked Email Creation

Easily create a new masked email address directly from within FMail3.

🔗

Deep Links, Hookmark & Linker

Copy a message:// deep link in both Fastmail and Apple Mail RFC-5322 formats. Full Hookmark and Linker support for personal linking workflows.

📄

Export to PDF

Save any email directly as a PDF from the File menu (⇧⌘P) — clean output with Fastmail UI chrome hidden.

🎨

Toolbar & Appearance

Customize or hide the toolbar with standard shortcuts. Inject your own JavaScript or CSS to tailor the Fastmail experience.

👁️

Auto-Hide & Focus

Lock a toolbar button to hide FMail3 automatically when it loses focus, or set a custom keyboard shortcut to toggle visibility.

🔒

Secure & Private

Sandboxed and notarized by Apple. Not running in your browser means better protection against web tracking. Mouse-over reveals hidden link destinations before you click. No user data collected — ever.

⚡

Lightweight & Modern

Under 10 MB, built with SwiftUI and Swift 6, fully adapted for macOS Tahoe, and regularly updated.