Proton 4.0 is now in beta

Proton V4 web beta brings persistent single sign-on in huge step toward full integration

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Today, we are marking a major milestone in our mission to expand privacy online with the launch of a new beta version of Proton Mail(new window) for web that includes crucial new features like Single Sign-On and persistent sessions (“remember me”). 

Today’s updates create the foundation of a fully integrated, private, and encrypted ecosystem covering all basic internet needs in a way that puts people first. These improvements are first coming to the web apps, but in the coming quarters they will also make it to mobile as we launch more apps and features that protect your digital privacy.

To achieve this, we have completely rebuilt our web apps using a new programming framework that will tie all our apps together. 

This beta update also includes new Proton Mail features, such as subfolders and multi-account access. And last but not least, we are deploying Proton Drive in closed beta for Lifetime account users.

While some of these new features and beta products are available only to users with paid plans, anyone can take advantage of the convenience of Single Sign-On and persistent sessions. To access them, go to and sign in to your Proton account.

Access all Proton services with just one login

Single Sign-On and persistent sessions make it possible to quickly access Proton Mail(new window), Proton Calendar(new window), Proton Drive(new window), and Proton Contacts and use them as a connected suite of tools. 

With Single Sign-On and persistent sessions, you don’t need to enter your username, password, and two-factor authentication every time you switch between apps or reopen your browser. You can simply sign in to your Proton account and start working in Proton Mail or Proton Calendar while keeping your data secure.

Single Sign-On

Single Sign-On allows you to easily switch between Proton Mail, Proton Contacts, Proton Calendar, and eventually Proton Drive without having to sign in again. 

For the time being, Proton VPN(new window) is being kept separate to give it stronger censorship resistance, as in certain countries Proton VPN is used to access the rest of the Proton services. While Single Sign-On is currently available only for Proton web apps, we will eventually include it in our Android and iOS apps. 

Persistent sessions

The new beta will also include persistent sessions for our web apps. This allows you to sign in to Proton, close your browser, and return later to your Proton Mail, Proton Calendar, and eventually Proton Drive without signing in again. For security reasons, your session will have a limited lifetime of 60 days if you are inactive, meaning you might need to log in again if you do not use one of our web apps for several weeks. That’s why it is critical to always remember your password(new window).

This feature is automatic. In practical terms, it means you will be able to go straight into your Proton account first thing in the morning without entering your login credentials at the start of every day.

Note: If you are using a shared device or are concerned about physical device compromise, you should log out of your Proton account to end your session. Closing the tab is no longer sufficient.

We completely rebuilt Proton Mail from the ground up

While you will quickly notice the new Single Sign-On feature, some of our most significant changes are invisible to users. We have written the new Proton Mail beta, as well as all our other new products, using the React programming framework. 

This is a crucial step that lays the foundation upon which we can build a fully integrated Proton suite in the future. Using React makes it much easier to incorporate Proton Mail with Proton Contacts, Proton Calendar, and Proton Drive, as well as any future Proton tools. Because of these changes, we will be able to design features that let you seamlessly move events from your inbox to your calendar or share files with your contacts.

Throughout this process, we have also improved our code to make it more maintainable. While this type of work does not generally result in noticeable user benefits, it is important to build a sound footing now in the early years of Proton, which will accelerate the delivery of updates and new features in the future and provide better performance for our users.


The new Proton Mail beta will also let you organize your messages into subfolders. You can add subfolders to any “parent” folder, and you will be able to make subfolders within subfolders (the maximum number of folder levels is three). Subfolders have been a popular request from Proton Mail users, and we are making them available to everyone, including free users. 

Multi-account access

The new Proton Mail beta will also include our multi-account feature, which allows you to be signed in to an unlimited number of accounts at the same time. This makes it easy to quickly manage multiple accounts, which is particularly useful for:

  • Business owners, who can quickly toggle through their different, role-based email accounts, responding to questions in support@, sales@, and admin@. 
  • Workers, who can easily switch between their personal and professional inboxes. 
  • Freelancers, who can create inboxes dedicated to important clients, allowing them to separate their workflows and stay organized.

Proton Drive early access

After months of internal testing, we are ready to share Proton Drive beta with our Lifetime account holders. If you have a Lifetime account, thank you for your exceptional support of our mission. You will shortly receive an email detailing how to start testing our encrypted cloud storage solution. 

We will then extend this early access beta to Visionary users before opening it up to all users with paid accounts. 

Proton Drive will greatly expand the possibilities of the Proton ecosystem and make it simple to privately store and share sensitive files. You can read more about how Proton Drive will secure your files in the Proton Drive security model(new window)

The next frontiers of freedom

One of the challenges of making privacy-focused tools is that they must be both secure and easy to use. The most secure email service in the world can’t protect any data if it is too complex for most people to use. The new Proton Mail beta is the first step toward a unified Proton that eliminates unnecessary steps and allows for the frictionless exchange of encrypted files and information between different Proton apps.

Screenshot of ProtonDrive.

Thank you to all our users. Your support is what makes our work possible. As with all our betas, we rely on your feedback to help us improve Proton. During the beta, you can send us your comments and feedback on the new Proton Mail inside the web app

To report issues, click Help > Report bug.

And let us know what you think of the Single Sign-On, multi-account support, and subfolder features in the new Proton Mail beta on Twitter(new window), Facebook(new window), Reddit(new window), Instagram(new window), and Linkedin(new window).

This is the next step toward building an internet where user privacy is the default. Thank you for helping us move online security, privacy, and freedom forward.

You can get a free secure email account from Proton Mail here(new window).

We also provide a free VPN service(new window) to protect your privacy. Proton Mail and Proton VPN are funded by community contributions. If you would like to support our development efforts, you can upgrade to a paid plan(new window). Thank you for your support.

Feel free to share your feedback and questions with us via our official social media channels on Twitter(new window) and Reddit(new window).

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Proton Team

We are scientists, engineers, and specialists from around the world drawn together by a shared vision of protecting freedom and privacy online. Proton was born out of a desire to build an internet that puts people before profits, and we're working to create a world where everyone is in control of their digital lives.

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