Paid email service Fastmail has released an official desktop application that supports Linux, macOS, and Windows. The app provides a standalone experience with system integrations beyond the web client. It arrives as an Electron-based wrapper, emphasizing privacy and ease of use for existing users.
Fastmail, a paid email provider known for its ad-free service and privacy focus, announced its new desktop app on October 15, 2025. The app mirrors the web client's interface and features, including mail layout options, behaviors, icons, theme tweaks, and account management settings. However, it operates as a windowed standalone application with enhanced system integrations such as dock icons, badging, the ability to set it as the default email client, offline support, desktop notifications, and dark mode compatibility.
Built as an Electron wrapper around the web client, the app offers deeper OS integration than a browser tab, making it easier for users to switch between applications, receive alerts, and handle system actions. For prolific Fastmail users, this setup simplifies email workflows compared to managing a browser tab. The service costs £5 a month after a 30-day free trial and avoids data tracking or ads, appealing to those prioritizing security, migration ease, and human support over free alternatives like Gmail.
While the Electron foundation—resulting in a roughly 300MB install size—may draw criticism, Fastmail's smaller scale makes a fully native app, such as one using GTK4/libadwaita, less feasible. On macOS, third-party wrappers leveraging Fastmail's open-source JMAP backend provide lighter alternatives at about 10MB. The app is not a general-purpose client like Thunderbird or Evolution; it is tailored exclusively to Fastmail accounts.
Downloads are available from Fastmail's website for Windows and macOS (Apple Silicon), while Linux users can access it via Flathub. The promotional materials highlight availability on Flathub alongside Windows and Apple icons, underscoring the platform's growing prominence in Linux distribution.