saasrankedSoftware, ranked on the facts

encrypted email service · Posteo e.K.

Posteo

German paid mailbox for 1 euro a month, with optional encryption of stored mail, contacts and calendar.

43/100

#7 of 9 encrypted email services
Facts checked 8 Oct 2026

In short

Posteo suits people who want a low-cost mailbox that opens in Thunderbird or Outlook over IMAP, with optional encryption of stored data1,2,4. Its transparency report is current, and it holds a German BSI certificate for secure mail transport6,7. The catch: encryption is opt-in, mail between Posteo users is not automatically end-to-end encrypted, and there are no native apps or custom domains3,4,5.

Best for: People who want a cheap mailbox that works in standard mail programs.

Where the points come from

Encryption19 of 27
Trust and audits4 of 26
Apps and access8 of 18
Mailbox2 of 13
Price10 of 16

Encryption 19 of 27 points

RuleWhat is publishedPoints
Stored mail the provider cannot readYesWith crypto mail storage on, Posteo says stored mail is no longer readable by it; the key is protected by your password4,8.10 / 10
Automatic end-to-end encryption between its own usersNoMail between Posteo users stays on its servers; end-to-end encryption is optional and needs S/MIME or OpenPGP keys set up by users4.0 / 8
Encrypted mail to other providersYesWebmail sends OpenPGP-encrypted mail through the Mailvelope browser extension; S/MIME is also supported2,4.6 / 6
Encrypted contacts or calendarYesOptional setting encrypts address book and calendar; Posteo says it cannot view the data9.3 / 3

Trust and audits 4 of 26 points

RuleWhat is publishedPoints
Independent audit since 2024Not publishedPosteo says Cure53 audited crypto mail storage, but gives no report, summary or date4,11.0 / 8
Open-source appsNot publishedPosteo says it uses open-source software, but names no licence or repository for its own apps2.0 / 6
SOC 2 Type II or ISO 27001Not publishedNot published on the vendor's security page; it names only a BSI TR-03108 certificate7.0 / 4
Transparency reportYesTransparency report has a 2025 section: 85 requests received6.4 / 4
Security key for two-factor sign-inNot publishedHelp page names YubiKey as an alternative to a TOTP app; FIDO2 or WebAuthn keys are not mentioned10,3.0 / 4

Apps and access 8 of 18 points

RuleWhat is publishedPoints
Official appsNoneOnly a web app and external mail clients are listed; no native apps2,3.0 / 10
Works in standard mail programsYesMailbox works with all devices and apps over IMAP and POP32.8 / 8

Mailbox 2 of 13 points

RuleWhat is publishedPoints
Your own domainNoFAQ says own domains are not supported5.0 / 5
Mail storage on the cheapest paid plan44 GB included in the 1 euro plan; can be raised to 75 GB2.2 / 5
Export your whole mailboxNot publishedNot published on the vendor's features page or FAQ; they describe only import into Posteo2,5.0 / 3

Price 10 of 16 points

RuleWhat is publishedPoints
Free plan with an encrypted mailboxNoFAQ says Posteo cannot offer free accounts5.0 / 6
Cheapest paid plan$1.12/moOne plan, 1 euro a month1. Converted at €1 = $1.118612.10 / 10

The rule behind each line: how we score encrypted email services.

Plans and prices

As the vendor lists them, before tax. Prices are in US dollars unless the plan shows euros; the points use US dollars, with euros converted at the ECB rate.

PlanPrice as listedPer monthNotes
Posteo mailbox1 person1 euro/month1,2–4 GB, 3 aliases; extra storage costs 0.25 euro per GB a month

Posteo shows its price in euros only; the build converts it to dollars1.

Strengths

  • Costs 1 euro a month for 4 GB, with no tiers to compare1.
  • Crypto mail storage covers existing and new mail, and Posteo says it cannot read it or switch the encryption off4,8.
  • Address book and calendar can be encrypted so that Posteo cannot view them9.
  • Works with standard mail programs over IMAP and POP32.
  • Publishes a transparency report with a 2025 section giving request counts6.

Limits

  • Posteo says it offers no free accounts5.
  • Own domains are not supported5.
  • Crypto mail storage is off until you turn it on, and a forgotten password means the archive is lost8.
  • Mail between Posteo users is not end-to-end encrypted automatically; OpenPGP or S/MIME must be set up4.
  • Only a web app is offered; no native desktop or mobile apps are listed2,3.

What Posteo e.K. says

Vendor claims. We show them, but they earn no points.

  • Posteo says its product offering uses only open-source software and free protocols2.

Other encrypted email services

  1. 1
    Proton MailPeople who want a free encrypted mailbox that grows into a paid one with custom domains and Outlook or Thunderbird access
    85/100
    $3.99/mocheapest paid plan
  2. 2
    Tuta MailPeople who want contacts and calendar encrypted too, and are fine using Tuta's own apps instead of a mail program
    73/100
    $3.36/mocheapest paid plan
  3. 3
    Forward EmailPeople with their own domain who want IMAP access and a low price
    56/100
    $3/mocheapest paid plan
  4. 4
    mailbox.orgPeople who want to read their mail in Thunderbird or Outlook and switch on encryption themselves
    49/100
    $1.12/mocheapest paid plan

All 9 encrypted email services

Sources

  1. Posteo, Posteo. Accessed 8 Oct 2026.
  2. Features, Posteo. Accessed 8 Oct 2026.
  3. Feature table, Posteo. Accessed 8 Oct 2026.
  4. Encryption, Posteo. Accessed 8 Oct 2026.
  5. FAQ, Posteo. Accessed 8 Oct 2026.
  6. Transparency report, Posteo. Accessed 8 Oct 2026.
  7. Security, Posteo. Accessed 8 Oct 2026.
  8. How do I activate Posteo crypto mail storage?, Posteo. Accessed 8 Oct 2026.
  9. How does encryption of the address book and calendar work?, Posteo. Accessed 8 Oct 2026.
  10. What is two-factor authentication and how do I set it up, Posteo. Accessed 8 Oct 2026.
  11. New: Posteo S/MIME add-on available now, Posteo. Accessed 8 Oct 2026.
  12. Euro foreign exchange reference rates: US dollar, European Central Bank. Accessed 8 Oct 2026.

Website: posteo.de/en · Markdown version · We are not affiliated with Posteo e.K..