Mailbox.org is a German email provider that has been operating since 2014 with a focus on privacy, transparency, and a complete office suite that goes beyond what ProtonMail or Tutanota offer. The product has not built brand recognition in the English-speaking privacy circles to the same degree as the better-known competitors. The product itself, however, is in some respects more capable.
This is the practical assessment after using Mailbox.org as a secondary email account for several months.
What Mailbox.org is
Mailbox.org is operated by Heinlein Support GmbH, a Berlin-based company that has been running email services since 1989 (originally as JPBerlin, focused on activist and NGO email). The current Mailbox.org product was launched in 2014.
Servers are in Germany, jurisdiction is German, GDPR applies fully. The company is privately held, founder-led, and has been operating consistently for decades.
The product is full email service plus a complete office suite (Open-Xchange-based) including encrypted calendar, contacts, tasks, file storage, and document collaboration. The pricing is unusually low for the feature set.
What Mailbox.org does well
The pricing is genuinely competitive. The Standard plan at €3 per month (€36 per year) gets you 30 GB of mail storage, custom domain, encrypted email with PGP support, full calendar, contacts, tasks, file storage, and Open-Xchange document editing. Compared to ProtonMail Plus at €4 per month for 15 GB and only mail-plus-calendar, Mailbox.org delivers significantly more features per euro.
The Open-Xchange office suite is a real differentiator. Inline document editing of common formats (Word, Excel, PowerPoint compatible) works in the browser. For users who need browser-based document editing without using Google Docs or Microsoft 365, this is meaningful.
PGP support is standard and well-implemented. You can use Mailbox.org as a normal email account with any standard email client (IMAP and SMTP supported), and PGP encryption works through Thunderbird with Enigmail or Apple Mail with appropriate plugins.
The company is highly transparent. Detailed terms of service, clear privacy policy, regular transparency reports, public information about staff and infrastructure.
The German jurisdiction provides strong privacy protections. The German privacy law tradition is more user-protective than US or UK standards.
The integration with German services (Deutsche Post identity verification, German tax software, etc.) is a benefit for German residents.
What Mailbox.org does less well
The marketing is essentially nonexistent. The brand has no presence in mainstream privacy-tools recommendations. When you mention Mailbox.org to non-Germans, you spend time explaining what it is.
The interface is functional but dated. The web client uses Open-Xchange, which is mature but not visually current. Compared to ProtonMail’s clean design, Mailbox.org feels more like a 2018 SaaS product.
The mobile apps are weak. Open-Xchange’s mobile apps are functional but not polished. For users who want a great mobile email experience, the standard Mail or Outlook apps configured for Mailbox.org via IMAP work better than the dedicated apps.
The English documentation is incomplete. While the user interface supports English, some configuration documentation and customer support resources are German-first. For non-German speakers, this can be friction.
The customer support is email-based, German business hours dominant. Response times in our experience were 24 to 48 hours.
The bundled features (Office, calendar, file storage) are not best-in-class compared to dedicated alternatives. Open-Xchange documents are functional but not as polished as Google Docs or Microsoft Office. The file storage is fine but not as featured as ProtonDrive or Sync.com.
Comparison with ProtonMail and Tutanota
| Feature | Mailbox.org | ProtonMail Plus | Tutanota Revolutionary |
|---|---|---|---|
| Annual cost | €36 | €48 | €36 |
| Storage | 30 GB | 15 GB | 20 GB |
| IMAP/SMTP | Yes | Via Bridge | No |
| PGP | Standard | Yes | Custom encryption (no PGP) |
| Subject line encryption | Via PGP only | No | Yes |
| Calendar | Yes | Yes | Yes |
| File storage | Yes (30 GB) | No (separate Drive) | No (separate Drive) |
| Office suite | Yes | No | No |
| Custom domain | Yes | Yes (alias only on Plus) | Yes |
| Mobile apps | Open-Xchange (mediocre) | Excellent | Functional |
| Web client polish | Functional | Excellent | Functional |
| Brand recognition | Low | High | Medium |
Mailbox.org wins on price-per-feature and on having a complete office suite included. ProtonMail wins on polish, mobile experience, and brand recognition. Tutanota wins on subject line encryption.
Use cases where Mailbox.org wins
You want a complete email-plus-office suite at one low price.
You value the German jurisdiction over Swiss or other options.
You will use IMAP/SMTP with standard email clients and that workflow matters.
You need integrated calendar, contacts, tasks, file storage, and email in one place.
You are a German resident or work with German services where Mailbox.org’s regional integrations matter.
You want a small, stable company with a multi-decade track record.
Use cases where Mailbox.org loses
You want polished mobile apps. ProtonMail or Apple Mail configured for Proton wins.
You want subject line encryption. Tutanota.
You want maximum brand recognition for the email address you give to non-technical recipients.
You want bundled VPN. ProtonMail Unlimited.
You want a service with English-first documentation and support.
A practical recommendation
For users wanting an email-plus-office suite at low cost: Mailbox.org Standard at €36 per year is excellent value.
For users wanting polished modern apps and brand recognition: ProtonMail Plus.
For users wanting maximum encryption coverage including subject lines: Tutanota.
For users in tight budgets who only want email: Posteo at €12 per year.
For most readers of this site who are not German residents and do not specifically value the office suite: ProtonMail or Tutanota are more practical recommendations.
For users who do want the office suite or who are based in Germany: Mailbox.org is genuinely the right answer and is meaningfully under-recommended in the English-speaking privacy press.
Mailbox.org | ProtonMail | Tutanota
Related: The day I left Gmail, Tutanota in 2026, StartMail review