Thundermail privacy rating

Summary

Thundermail scores 40 out of 100 (grade D) on the email providers criteria. It meets 4 of 21 criteria: open source, open protocols, custom domains and SMTP submission. It partly meets no ads or data sales, TLS configuration, security headers, modern web standards, end-to-end encryption, encrypted mailbox storage, email security standards and IMAP support. It does not meet no trackers or telemetry, independent audit, transparency report, tells users about requests, sign up without personal data, POP3 support, mail transport security, Sender Rewriting Scheme and ARC sealing. It is based in the United States: Five Eyes member; subject to the US CLOUD Act. Automated tests: SSL Labs grade B, Mozilla HTTP Observatory grade B, Internet.nl website score 75% and Internet.nl email score 72%.

Score 40 out of 100. How scoring works

Criteria

• ✔Yes

  Open source ×3Weight 3 of 3

  Is all the source code needed to run the product public?

  The account service, webmail and deployment code are published under MPL-2.0. The mail server is Stalwart, which is AGPL-3.0 with some enterprise features under a source-available license.

  raw.githubusercontent.com

• ✖No

  No trackers or telemetry ×3Weight 3 of 3

  Are the website and apps free of third-party trackers, with any analytics anonymous and any telemetry off by default?

  The home page loads no third-party trackers, but the privacy policy allows third-party analytics cookies. The account service sends sign-up and login events to PostHog under a hashed user ID.

  tb.pro

• ◐Partial

  No ads or data sales ×2Weight 2 of 3

  Is the product funded without advertising, ad targeting or selling user data?

  Funded by subscriptions, with no ads in the service. The privacy policy states that identifiers and browsing data are shared with analytics providers and social networks in the sense of US state privacy law.

  tb.pro

• ✖No

  Independent audit ×2Weight 2 of 3

  Has an independent security or privacy audit been published within the last three years?

  No independent audit is published.

• ✖No

  Transparency report ×2Weight 2 of 3

  Does the provider regularly publish how many government and legal requests it receives and how it responds?

  No transparency report covers Thundermail. Mozilla's reports cover Mozilla Corporation, and MZLA is a separate company.

  mozilla.org

• ✖No

  Tells users about requests ×1Weight 1 of 3

  Does the provider promise to tell users about requests for their data, unless a court forbids it?

  No published policy on notifying users about data requests. The privacy policy only says data may be disclosed to authorities in response to lawful requests.

  tb.pro

• ◐Partial

  End-to-end encryption ×3Weight 3 of 3

  Can mail be end-to-end encrypted so that the provider cannot read message contents?

  OpenPGP is built into the Thunderbird app but needs a key set up for each account. Files sent with Send are end-to-end encrypted.

  support.mozilla.org

• ◐Partial

  Encrypted mailbox storage ×3Weight 3 of 3

  Is stored mail encrypted with a key the provider does not hold?

  Mail is stored on encrypted AWS disks and S3 buckets, with keys the provider holds. The privacy policy lists cases in which staff may access mail.

  raw.githubusercontent.com

• ✔Yes

  Open protocols ×2Weight 2 of 3

  Can any standard app connect over IMAP, POP3, SMTP, CalDAV or CardDAV, without extra software?

  IMAP, SMTP and JMAP work with any client. POP3 is not offered.

  tb.pro

• ✔Yes

  Custom domains ×1Weight 1 of 3

  Can mail be sent and received with your own domain?

  The Early Bird plan includes up to three custom domains.

  tb.pro

• ✖No

  Sign up without personal data ×2Weight 2 of 3

  Can an account be created without a phone number or another email address?

  An existing email address is required to join the waitlist and verify the account. A paid subscription is also required.

  tb.pro

• ✖No

  Sender Rewriting Scheme ×1Weight 1 of 3

  Is the envelope sender rewritten with SRS when mail is forwarded, so forwarded mail keeps passing SPF?

  No published documentation on SRS for forwarded mail.

• ✖No

  ARC sealing ×1Weight 1 of 3

  Does the provider validate and add ARC (RFC 8617) signatures, so authentication results survive forwarding?

  No published documentation on ARC signing or validation.

Automated tests

• ◐Partial

  TLS configuration ×2Weight 2 of 3

  Does the website pass the Qualys SSL Labs test with a grade of A or better?

  Grade B

  ssllabs.com

• ◐Partial

  Security headers ×1Weight 1 of 3

  Does the website pass the Mozilla HTTP Observatory test with a grade of A or better?

  Grade B (70/100+)

  developer.mozilla.org

• ◐Partial

  Modern web standards ×1Weight 1 of 3

  Does the website score 90% or higher on the Internet.nl website test?

  Score 75%

  batch.internet.nl

• ◐Partial

  Email security standards ×2Weight 2 of 3

  Does the mail domain score 90% or higher on the Internet.nl email test?

  Score 72%

  batch.internet.nl

• ◐Partial

  IMAP support ×2Weight 2 of 3

  Does the IMAP server accept connections over implicit TLS on port 993 and advertise IMAP4rev1 or IMAP4rev2 with IDLE push?

  mail.thundermail.com:993 (implicit TLS). IMAP4rev2 advertised, no IDLE before login.

• ✖No

  POP3 support ×1Weight 1 of 3

  Does the POP3 server accept connections over implicit TLS on port 995 and answer CAPA with UIDL?

  Not offered.

• ✔Yes

  SMTP submission ×2Weight 2 of 3

  Does mail submission work over implicit TLS on port 465 with SMTPUTF8, 8BITMIME, PIPELINING and AUTH?

  mail.thundermail.com:465 (implicit TLS). SMTPUTF8, 8BITMIME, PIPELINING and AUTH advertised.

• ✖No

  Mail transport security ×3Weight 3 of 3

  Does the mail domain enforce encrypted, authenticated delivery with MTA-STS, DANE, DNSSEC, TLS-RPT and an enforced DMARC policy?

  Passes: SPF, DMARC reject, TLS-RPT. Missing: MTA-STS testing, DNSSEC, DANE none.

Email standards

• ✔Yes: Mail serversMXmail.thundermail.com
• ✔Yes: RFC 7208 sender policySPFpublished
• ✔Yes: RFC 7489. Quarantine or reject counts as enforcedDMARCp=reject
• ✖No: RFC 8461 strict transport securityMTA-STStesting
• ✔Yes: RFC 8460 TLS failure reportsTLS-RPTpublished
• ✖No: RFC 4033 signed DNSDNSSECnot validated
• ✖No: RFC 7672 TLSA records on MX hostsDANEnone
• ✖No: Brand logo record (not scored)BIMInone
• ✔Yes: RFC 6186 and RFC 8314 service records (not scored)SRVclient autoconfiguration published

Capabilities are what each server advertises before login. How these tests work