{
  "slug": "thunderbird-for-android",
  "category": "email-clients",
  "name": "Thunderbird for Android",
  "description": "Open-source email app for Android from the Thunderbird project, based on K-9 Mail, which remains available as a variant. Works with any IMAP, POP3 and SMTP provider.",
  "website": "https://www.thunderbird.net/en-US/mobile/",
  "source": "https://github.com/thunderbird/thunderbird-android",
  "license": "Apache-2.0",
  "platforms": [],
  "jurisdiction": {
    "code": "US",
    "name": "United States",
    "eyes": "Five Eyes",
    "eu": false,
    "gdpr": false,
    "cloud_act": "provider"
  },
  "pick": false,
  "pick_reason": null,
  "disclosure": null,
  "grade": "B",
  "score": 89,
  "coverage": 100,
  "summary": "Thunderbird for Android scores 89 out of 100 (grade B) on the email clients criteria. It meets 6 of 8 criteria: open source, no trackers or telemetry, no ads or data sales, connects directly, blocks remote content and works with any provider. It partly meets independent audit and OpenPGP support. It is based in the United States: Five Eyes member; subject to the US CLOUD Act.",
  "url": "https://privacyratings.com/email-clients/thunderbird-for-android/",
  "markdown": "https://privacyratings.com/email-clients/thunderbird-for-android/index.md",
  "answers": {
    "open_source": {
      "title": "Open source",
      "weight": 3,
      "answer": "yes",
      "evidence": "https://github.com/thunderbird/thunderbird-android/blob/main/LICENSE",
      "note": "Apache-2.0."
    },
    "no_trackers": {
      "title": "No trackers or telemetry",
      "weight": 3,
      "answer": "yes",
      "evidence": "https://support.mozilla.org/en-US/kb/thunderbird-android-telemetry",
      "note": "Collects no telemetry, and any future telemetry is opt-in. Exodus finds 0 trackers."
    },
    "no_ads": {
      "title": "No ads or data sales",
      "weight": 2,
      "answer": "yes",
      "evidence": "https://www.thunderbird.net/en-US/mobile/",
      "note": "Free app funded by donations. No ads."
    },
    "independent_audit": {
      "title": "Independent audit",
      "weight": 2,
      "answer": "partial",
      "evidence": "https://7asecurity.com/reports/pentest-report_k-9_mail.pdf",
      "note": "7ASecurity audited K-9 Mail, now Thunderbird for Android, with OSTIF and published the full report, but it is more than three years old. The app also passes Google's annual CASA Tier 2 assessment, and only the certification is public (github.com/thunderbird/thunderbird-android/security)."
    },
    "transparency_report": {
      "title": "Transparency report",
      "weight": 2,
      "answer": "n/a",
      "evidence": null,
      "note": "Only applies to hosted services with a website to test."
    },
    "user_notice": {
      "title": "Tells users about requests",
      "weight": 1,
      "answer": "n/a",
      "evidence": null,
      "note": "Only applies to hosted services with a website to test."
    },
    "tls": {
      "title": "TLS configuration",
      "weight": 2,
      "answer": "n/a",
      "evidence": null,
      "note": "Only applies to hosted services with a website to test."
    },
    "security_headers": {
      "title": "Security headers",
      "weight": 1,
      "answer": "n/a",
      "evidence": null,
      "note": "Only applies to hosted services with a website to test."
    },
    "web_standards": {
      "title": "Modern web standards",
      "weight": 1,
      "answer": "n/a",
      "evidence": null,
      "note": "Only applies to hosted services with a website to test."
    },
    "openpgp": {
      "title": "OpenPGP support",
      "weight": 2,
      "answer": "partial",
      "evidence": "https://docs.k9mail.app/en/6.400/security/pgp/",
      "note": "PGP needs the separate OpenKeychain app."
    },
    "no_cloud_relay": {
      "title": "Connects directly",
      "weight": 3,
      "answer": "yes",
      "evidence": "https://www.mozilla.org/en-US/privacy/thunderbird/",
      "note": "Connects directly to mail servers. Mail, contacts and account details stay on the device."
    },
    "remote_content_blocked": {
      "title": "Blocks remote content",
      "weight": 2,
      "answer": "yes",
      "evidence": "https://docs.k9mail.app/en/6.400/settings/account/#always-show-images",
      "note": "Images load only after tapping Show pictures unless the user changes this setting."
    },
    "any_provider": {
      "title": "Works with any provider",
      "weight": 1,
      "answer": "yes",
      "evidence": "https://docs.k9mail.app/en/6.400/accounts/incoming_imap/",
      "note": "Works with any IMAP, POP3 and SMTP provider."
    }
  },
  "tests": {
    "ssllabs": null,
    "observatory": null,
    "internetnl_web": null,
    "internetnl_mail": null,
    "trackers": [],
    "tested_at": "2026-10-01T07:00:27.960Z"
  },
  "last_modified": "2026-10-01T07:44:20Z"
}