Let's celebrate nine years of open source!

We would like to use the occasion of our celebration to thank all of you for your continuous support. You are helping us to build an open source email service that can challenge mainstream services such as Gmail, Yahoo, Zoho and Outlook.

The road to open source

Building a service that offers true open source email is very difficult as a lot of services from Google are so convenient for developers to integrate into their products that is takes a lot of effort to replace these. That's why you will find Google dependencies in many services - even secure ones. These services often use Google for push notifications on Android or Google's reCaptcha service.

The problem: when integrating Google services into your product, you open the door to the Big Tech service Google who is then able to see your customers' data. That's why we at Tutanota never choose the easy way out. Instead we have built our own open source captcha and our own notification service on Android.

Because when we promise privacy, we guarantee privacy - particular from Big Tech tracking.

If you love this message, share our video that illustrates why you need a private email alternative!

Our path

Our first step on our road to open source was to publish the Tutanota webmail client as open source on GitHub in September 2014. Shortly after that, we published open source apps for Android and iOS.

Today, we would like to take a moment to thank the hundreds of people who have downloaded and built the Tutanota client locally on their device, reported bugs and security issues as well as fixed bugs and added small improvements or helped with our translation project.

It is amazing to see that to date already more than 5.ooo people have starred our project on GitHub and 500 have forked it!

Join our open source project!

We are happy about everyone joining us in our efforts to bring privacy to the world! Feel free to join us by

• Checking our code on GitHub
• Translating Tutanota to your native language
• Or simply by spreading the word about Tutanota among your friends and on social media.

Giving back

Open source also comes with the idea to give something back to the community. That's why we donate Tutanota to open source teams.

We love to see how our community is growing as we are at a turning point: With Big Tech dominance and the rise of AI, now is the time that people realize how important their own data and their privacy has become. We are incredibly happy that together we are at the forefront of this privacy and open source revolution!

You can help spread privacy across the globe by inviting your friends to join the privacy revolution! To make this even more attractive to you, you will get one year for free after you've invited four of your friends. 😍

As a privacy-first open source project, we would never use marketing tactics that track or profile users so word-of-mouth is one of the most important pillars for Tutanota's success.

Why open source is important

Open source is crucial to any security service. Open source guarantees that lots of people can scrutinize the code to make sure no security weaknesses exist within the code. Open source also makes it impossible to sneak an encryption backdoor into the code.

By being open source, we at Tutanota can prove that we actually do what we say: protecting your emails. That's why publishing all Tutanota clients as open source is a must. Even the Five Eyes countries can not spy on your emails if these are encrypted end-to-end like in Tutanota.

Important open source milestones

To make Tutanota the best open source email service, we built our own captcha for being able to prevent abusive mass sign-ups without relying on Google's reCaptcha. Lots of email services, even secure ones, rely on Google's reCaptcha, but this was never an option for us.

The hardest part, however, was to replace Google's push notification service, which we originally used for the Android app. This was necessary for two reasons:

• First, we wanted to release the Android app on F-Droid, and F-Droid does not allow any Google dependencies - which is awesome!

• Second, we wanted to include more information in the push notification, which is impossible when using Google's push notification service as this service can read any data included in the notification.

Finally, we succeeded in building our own notification service.

If you are interested in how we managed to replace Google's push notification service, read this technical post.

Tutanota - the Google-free email service

With the app release on F-Droid, Tutanota now proves that it is possible to build a secure email service that is completely Google-free, giving people a real open source email alternative to services like Gmail, Yahoo, Hushmail, GMX, Outlook, Fastmail, Posteo, Startmail, Mailbox.org and Protonmail.

Special challenges due to the encryption

Usage on desktops

Due to the encryption, Tutanota can not be connected with external mail clients via IMAP or POP. Tutanota manages and stores the encryption keys for you. With the help of your password, you can decrypt your keys and then also your data.

This automatic management of encryption keys would not be possible if we enabled integration of Tutanota into external mail clients. To achieve this, it would be necessary to decrypt the data before it reaches the external mail client - which would then defy the concept of end-to-end encryption.

Nevertheless, we understand that our users need to be able to handle their emails locally on a desktop and also to connect multiple email services within one client. To fully comply with user expectations while maintaining our high level of security and privacy, we have identified four challenges:

1. Building desktop clients

We have built and published the Tutanota desktop clients end of 2018. These clients are published as open source and you can even verify the signature after downloading the client. Beginning of 2021 we executed an extensive security review of the desktop clients to push them out of beta. You can check the results of the security review here.

We can now safely say that using Tutanota via our desktop clients is the most secure way. You can download the clients here.

2. Offline support

When fetching emails via third party clients, e.g. Thunderbird or Outlook, these emails are also stored locally and are available all the time. Emails stored in Tutanota are normally only available when being online.

But this has changed now: In 2022 we managed to implement offline mode in the Tutanota desktop clients and apps. You can now check your emails, calendars, and contacts even without access to the internet!

To keep local memory usage low, particularly on mobile devices, Tutanota usually stores the emails from the last month locally. If you need more emails than this, you can change the timeframe in Settings.

3. Email import

Importing and encrypting large mailboxes into Tutanota will take up a lot of traffic and computing power. Nevertheless, it is understandable that professional users of Tutanota want to import their old mailboxes and secure them within Tutanota.

We are in the process of upgrading our infrastructure to enable email import and will soon implement this feature. You can check our roadmap for more details.

4. Conversation view & labels

As most desktop clients as well as webmail providers support conversation view, demand for this feature was enormous in the past. We are happy that by now all Tutanota clients support conversation view. We now have to finish the feature so that only the latest email of a conversation is displayed in your inbox or folder. In addition we plan to add labels to Tutanota so that you can sort your emails even better compared to the current option to use folders and subfolders.

Privacy done right

Privacy and security are at the heart of Tutanota, and as our development steps prove, we never compromise on that. This clear focus on privacy is only possible because we own Tutanota. We don't have to explain our development decisions to big investors, shareholders or any other third party.

To this day, Tutanota has grown organically: With the rising number of paying users, we have employed more developers. So you'll be as excited as we are to hear that in the coming months we will continue to onboard more developers at our offices in Hanover!

All of this is only possible because of your continuous support. We are very grateful to have such an awesome and loyal user base. We will keep working hard to earn your trust.

Thank you!