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SPECIFICTION
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Mozilla Thunderbird

thunderbird.net

Free plan Open source WindowsmacOSLinuxAndroid
Visit thunderbird.net
Spec score 8.8 #16 of 142 in Email clients

What it is

Mozilla Thunderbird is a free, open-source email application for Windows, Linux, macOS, and Android. Users can manage multiple accounts separately or combine them in a unified inbox. The app includes calendar, contacts, and task tools; desktop users can also work offline and schedule messages. Its interface is customizable, and it supports third-party add-ons. Thunderbird says it does not put ads in the inbox or sell inbox advertising, and that user donations fund the project. It describes privacy and security as priorities and says its open-source code has been reviewed and improved over 20 years. The application is part of MZLA Technologies Corporation, owned by Mozilla.org. Help and getting-started resources are available for desktop and mobile users, with contributors around the world supporting the project. Thunderbird is available free forever, with donations optional; its listed mobile platform is Android.

Spec sheet

Free plan
YesRead 21 Sep 2026 · thunderbird.net
Founded
2003Read 28 Sep 2026 · thunderbird.net
Ad Free
Thunderbird does not clutter the inbox with ads or commercials.Read 27 Sep 2026 · thunderbird.net
Calendar tools
YesRead 21 Sep 2026 · thunderbird.net
Code Review
Its open-source code has been reviewed and improved over 20 years.Read 27 Sep 2026 · thunderbird.net
Community Support
Contributors around the world help users and support the project.Read 27 Sep 2026 · thunderbird.net
Customizable Interface
The interface is customizable for different workflows and visual preferences.Read 27 Sep 2026 · thunderbird.net
Desktop Platforms
The desktop app supports Windows, Linux, and macOS.Read 27 Sep 2026 · thunderbird.net
Donation Funded
Thunderbird is funded by user donations and says it does not sell inbox ads.Read 27 Sep 2026 · thunderbird.net
Email Management
Users can manage multiple email accounts separately or in a unified inbox.Read 27 Sep 2026 · thunderbird.net
Free Forever
Thunderbird is available free forever.Read 27 Sep 2026 · thunderbird.net
Language Options
The site provides a broad selection of page languages.Read 27 Sep 2026 · thunderbird.net
Mobile Platform
Thunderbird Mobile is an open-source email app for Android.Read 27 Sep 2026 · thunderbird.net
Offline access
YesRead 21 Sep 2026 · thunderbird.net
Open Source
Thunderbird is open source and freely licensed to use, modify, and share.Read 27 Sep 2026 · thunderbird.net
Operating Entity
Thunderbird is part of MZLA Technologies Corporation, owned by Mozilla.org.Read 27 Sep 2026 · thunderbird.net
Privacy And Security
Thunderbird says privacy and security are prioritized as part of Mozilla.Read 27 Sep 2026 · thunderbird.net
Productivity Tools
Thunderbird includes calendar, contacts, and task management.Read 27 Sep 2026 · thunderbird.net
Scheduled sending
YesRead 21 Sep 2026 · thunderbird.net
Support Resources
Users can find desktop and mobile help, support, and getting-started resources.Read 27 Sep 2026 · thunderbird.net
Third Party Add-ons
Thunderbird supports a third-party add-on ecosystem.Read 27 Sep 2026 · thunderbird.net
Unified inbox
YesRead 21 Sep 2026 · thunderbird.net

Plans and prices

Free Free Email, calendar, and contacts · Multiple account support · Open-source software Read 21 Sep 2026 · thunderbird.net
Free forever Free Donate to make it better. Read 27 Sep 2026 · thunderbird.net

Every Mozilla Thunderbird plan and price →

Strong points and limits

Strong points

  • Free forever and open source
  • Multiple accounts can use a unified inbox
  • Includes calendar, contacts, and task management
  • Desktop app supports offline access and scheduled sending
  • Customizable interface with third-party add-ons

Limits

  • Listed mobile platform is Android only
  • Funding relies on user donations
  • Desktop platforms are Windows, Linux, and macOS

Who it suits

Thunderbird suits people who want to manage multiple email accounts alongside calendar, contacts, and tasks. It also fits users looking for open-source software with desktop and Android versions.

Verdict

Thunderbird combines multi-account email with calendar, contacts, and task tools at no charge. Its desktop and Android availability, offline access, and add-ons are useful details for choosing a setup.

Where Specifiction places it

Alternatives to Mozilla ThunderbirdAll alternatives →