Open Source Alternatives to Microsoft Outlook

An email client included as part of the Microsoft 365 productivity suite. The software provides email management capabilities and integrates with Microsoft Copilot to provide AI assistance within the application. It is designed for individuals, families, and business users and is deployed as a desktop app on PCs and Macs, as well as on tablets and phones. The product is used to manage communications and is bundled with other productivity tools and cloud storage. Users can access the software through various subscription tiers that provide ongoing security updates, technical support, and the latest feature releases. The application operates across multiple devices to allow for consistent access to messages and schedules. It functions as a core component of a broader ecosystem that includes word processing, spreadsheets, and presentation software for personal and professional use.

Whether you want to cut software costs or escape vendor lock-in, these open source alternatives to Microsoft Outlook give you an option you fully own. Run them on your own server or desktop, so your data stays under your control. This page lists 2 open source alternatives to Microsoft Outlook. The most popular are Mailspring and Cypht. Most use the GPL-3.0 or LGPL-2.1 license, and 1 offers an official Docker image.