# Mozilla Thunderbird privacy rating

Open-source desktop email client for Windows, macOS and Linux with calendar, contacts and built-in OpenPGP and S/MIME encryption.

## Summary

Mozilla Thunderbird scores 86 out of 100 (grade B) on the email clients criteria. It meets 6 of 8 criteria: open source, no ads or data sales, OpenPGP support, connects directly, blocks remote content and works with any provider. It partly meets no trackers or telemetry and independent audit. It is based in the United States: Five Eyes member; subject to the US CLOUD Act.

- Website: https://www.thunderbird.net
- Source code: https://github.com/mozilla/releases-comm-central
- Jurisdiction: United States. Five Eyes member. Subject to the US CLOUD Act.
- Home page trackers: none found
- Category: [Email clients](https://privacyratings.com/email-clients/)
- Also rated: [Thunderbird for Android](https://privacyratings.com/email-clients/thunderbird-for-android/) (Email clients)
- Grade: B (86/100)

## Criteria

| Criterion | Answer | Note | Evidence |
| --- | --- | --- | --- |
| Open source | Yes | MPL-2.0. | https://www.mozilla.org/en-US/MPL/2.0/ |
| No trackers or telemetry | Partial | Sends first-party telemetry to Mozilla by default, which can be turned off in settings. | https://support.mozilla.org/en-US/kb/thunderbird-telemetry |
| No ads or data sales | Yes | Funded by user donations. No ads. | https://www.thunderbird.net/en-US/donate/ |
| Independent audit | Partial | Cure53 audited Thunderbird and Enigmail, but only a summary is public and the audit is more than three years old. | https://posteo.de/en/blog/security-warning-for-thunderbird-users-and-enigmail-users-vulnerabilities-threaten-confidentiality-of-communication |
| OpenPGP support | Yes | OpenPGP and S/MIME are built in. | https://support.mozilla.org/en-US/kb/openpgp-thunderbird-howto-and-faq |
| Connects directly | Yes | Connects directly to mail servers. Mail, contacts and account details stay on the device. | https://www.mozilla.org/en-US/privacy/thunderbird/ |
| Blocks remote content | Yes | Remote content is blocked by default. | https://support.mozilla.org/en-US/kb/remote-content-in-messages |
| Works with any provider | Yes | Works with any IMAP, POP3 and SMTP provider. | https://support.mozilla.org/en-US/kb/manual-account-configuration |

Source: https://privacyratings.com/email-clients/mozilla-thunderbird/
Edit: https://github.com/privacyratings/privacyratings.com/edit/main/ratings/email-clients/mozilla-thunderbird.md