What it does
Thunderbird is an email, calendar and contacts client with desktop and Android editions. The project states that it does not sell inbox ads or train AI on private conversations.
Thunderbird manages existing accounts rather than providing the mailbox itself. Accounts can remain separate or appear in a unified inbox, with calendars and contacts in the same app. That makes it a practical choice when the provider is staying but the current client is not.
The project publishes its source and describes a donation-funded model without inbox advertising or use of private conversations for AI training. Desktop downloads cover Windows, macOS and Linux, while the Android edition is a related mobile client. Features should be checked for the chosen edition rather than assuming desktop and phone behavior is identical.
Strengths
- Existing accounts can be managed separately or in a unified inbox.
- Desktop and Android editions are offered.
- The client is open source and donation-funded.
Best for
- People who want a privacy-focused client for existing email accounts
Sources
- Thunderbird — Free Your Inbox. — Thunderbird (Oct 26, 2026)
- Thunderbird official project license (Oct 26, 2026)