We are kicking off the development of email import!

Email import is coming to your secure Tutanota mailboxes.

We are now working on email import for Tutanota
We are excited to let you know that we are working on an import feature for Tutanota. As an end-to-end encrypted email service, we do not want to import your emails directly to our servers. When importing any of your data to Tutanota, we always make sure that our server can never read any of it. This zero-knowledge approach is a challenge, particularly for emails, but we already have an idea how to tackle it!

Email import is one of the highest requested features from our community, and we are very happy that we are now actively working on this feature.

While we would have wanted to start this feature much earlier, we had to put a lot of work into the server-side first.

During the last year, we have been working on the largest server restructuring ever done for Tutanota. This was required to prepare Tutanota for further growth as well as to prepare for the higher loads that we will be seeing as soon as we release the import feature.

The server improvements that we implemented include:

  • New and much improved DDoS protection

  • Migrated the entire infrastructure to new more powerful servers

  • Set up a new distributed storage system

  • Set up a new multi homed network infrastructure

As we have made great progress with the server-side, we are now ready to actually start implementing the email import feature!

Find out more on how we develop at Tutanota.

Kicking off email import

Today we are excited to kick-off email import!

Beginning of December Johannes joined our team to do his Master's thesis at Tutanota with the title:

"Towards Zero Knowledge – Adaptive Client-Side Mailbox Migration for End-to-End Encrypted Email Communication"

Objective of email import

The goal is that email import will be implemented in the Tutanota native desktop clients for Linux, Windows and macOS.

We plan to develop a client-side email migration system which

  1. Ensures that the principle of zero-knowledge encryption is secured at all times (except for minimum necessary metadata).

  2. Adaptively finds and optimizes for the best email throughput (adaptive load control) by relying on important metrics such as e.g. server rate limits, amount of parallel connections as well as connection stability.

User scenarios

The email import feature in Tutanota should cover two user scenarios:

Scenario 1: Single user import

"As a user I want to import my existing mailbox from a different provider into my Tutanota mailbox, so that I do not lose my old emails and do not have to maintain a second account."

You can find the correlating GitHub issue here.

Scenario 2: Multi user import

"As a company or family admin I want to migrate all mailboxes of my company or family from a different provider to Tutanota, so I do not lose any old email conversations and do not have to maintain a second mail infrastructure or email server."

You can find the correlating GitHub issue here.


The email import feature should take the following requirements into account:

  1. The email import should be fast.

  2. The email import should be as efficient as possible without the need to configure any connection and timing parameters, so that the email import is finished as quickly as possible without blocking other running processes. Users still need to be able to use the system for other purposes.

  3. The email import in Tutanota should preserve the same folder structure as was used with the previous email provider.

  4. The email import can be paused and continued later so that the computer does not need to keep running all the time.

For being able to satisfy requirement number 3, it is necessary that we implement support for subfolders in our folder structure first. That's why we are also starting to work on subfolders now and expect to release this feature in the coming weeks.

You can track the progress of subfolders here.

Motivation of the master's thesis

Or: Why does Tutanota need an email import feature?

"Within the market of end-to-end encrypted email providers the service Tutanota stands out for its simplicity and strong encryption guarantees. Tutanota is in fact the world’s first end-to-end encrypted email service that encrypts the entire mailbox. Started as a secure email service in 2011, Tutanota now additionally offers an encrypted address book, an encrypted calendar and the encrypted contact form Secure Connect.

Switching to Tutanota comes along with a lot of benefits:

  1. Tutanota provides a fully end-to-end encrypted and entirely tracking free mailbox.

  2. Especially companies benefit from smooth secure and confidential internal communication as well as from encrypted external communication based on the concept of encrypting emails with a shared password.

  3. Generally, outsourcing your email provider (in contrast to hosting an email server yourself) reduces necessary maintenance costs, that can quickly become overwhelming.

To ensure zero-knowledge end-to-end encryption Tutanota uses a complex independently developed cryptosystem, that is published under the GNU General Public License v3.0 3.

Different to other end-to-end encrypted email providers, Tutanota does explicitly not use the OpenPGP Message Format in order to further improve the security level. This relates from the fact, that OpenPGP, in its standard form, does not support subject encryption, has no option for Perfect Forward Secrecy (PFS) and furthermore does not provide an uncomplicated procedure to update the cryptographic algorithms.

In fact, Tutanota has at present implemented a first prototype using post-quantum secure algorithms and already today supports true subject encryption as well as plans to support Perfect Forward Secrecy (PFS).

Tutanota requires the use of their own clients and is not compatible with standard mail clients, such as Thunderbird, but by that is enabling further functionalities such as a zero-knowledge calendar and contact storage.

Despite the many advantages that Tutanota brings along, users typically do not want to leave their existing email communication behind and therefore need the ability to migrate their mailbox."

To enable everyone to use the fully encrypted Tutanota mailbox, email import is one of the most important features.

We are really excited that we can now kick off implementing email import!

We'd like to thank you for your continuous support and for helping our mission of bringing privacy to the world.