Thunderbird is a free email application. Makes email better for you, bringing together speed, privacy and the latest technologies. Focus on what matters and forget about complexity. Multiple features, such as built-in Do Not Track and remote content blocking, work together to ensure your safety and privacy, so you can have peace of mind. With Add-ons (Extensions & Themes) and many more features you can change the look and feel of Thunderbird in an instant. Organize your schedule and life’s important events in a calendar that’s fully integrated with your Thunderbird email. Manage multiple calendars, create your daily to do list, invite friends to events, and subscribe to public calendars.