FMail3

FMail3 provides a native macOS interface that encapsulates Fastmail’s web service within a traditional desktop application. It presents the full set of Fastmail features while integrating with macOS window management, tabs, and system notifications, eliminating the need for a browser‑based workflow. The app runs in a sandboxed, notarized environment and does not collect user data.

Users can open multiple Fastmail views as separate windows or macOS tabs, with automatic saving and restoration of scroll position, navigation history, and open conversations. Real‑time inbox counts are displayed in the Dock and menu bar via Fastmail’s JMAP push connection, and native macOS notifications include a quick delete action. The application can be set as the default email client, handling mailto: links, and supports a compose‑in‑window mode for focused drafting.

Additional capabilities include one‑click creation of masked email addresses, deep‑link generation in message:// format, and full Hookmark support for personal linking workflows. Toolbar visibility and appearance can be customized, and users may inject JavaScript or CSS to tailor the Fastmail experience. The lightweight SwiftUI‑based binary remains under 10 MB and is built for macOS Tahoe.