How to use read receipts

A read receipt is a notification to the sender of an email that the recipient has seen the message. ProtonMail allows you to send read receipts upon request, as well as request read receipts from your recipients. You can also decline to send read receipts, and no notifications of any […]

Update required

Our developers regularly release software updates that improve the security, reliability, and user experience of ProtonMail. Most of these new versions are recommended but not strictly required. On some occasions, however, we will release versions of our software that are required for all users. A required update means that any […]

Email bomb mitigation

An email bomb is a kind of online attack in which the attacker sends a massive amount of emails to a specific address or computer network in order to overflow the inbox of the recipient. An increasingly common form of this attack consists of bombarding the user mailbox with signup […]

Sender Verification Failed

Note: This article refers to a feature that is still in beta and not yet released on the public version of ProtonMail. ProtonMail employs different methods to protect your privacy and your security. One method of protecting messages from being read by outsiders is encryption. However, encryption alone does not […]

Address Verification with Trusted Keys

By default, ProtonMail distributes all of the cryptographic keys that are needed for communicating between users. This ensures that any ProtonMail user can seamlessly encrypt mail to any other ProtonMail user, with no possibility of data being intercepted. This approach makes sure all internal ProtonMail communications are encrypted, but it […]

How to use PGP

PGP is a time-tested and proven method of protecting email communications with end-to-end encryption (which prevents emails from being read by any third parties, including the email provider). Historically, PGP has been difficult to use, and it was not possible for most users to set up and regularly use PGP. […]

Accessing onion sites in Firefox

Tor is a hidden network that encrypts and anonymizes your internet connection, giving users increased security, privacy, and resistance to censorship. ProtonMail provides email access over the Tor network through our onion site at https://protonirockerxow.onion. To access the ProtonMail onion site, you must first connect to Tor. An easy way […]

Operating systems supported by the Bridge

The Bridge is supported on Windows 7 and above and macOS 10.11 (El Capitan) and above. The ProtonMail Bridge application for Linux is currently in open beta, with the full version currently in development. Linux users interested in joining the open beta should email our team at bridge@protonmail.ch. We will […]

Clients supported by the Bridge

The Bridge is an application that integrates your ProtonMail account with IMAP and SMTP email programs. The Bridge gives users the security and privacy benefits of ProtonMail within the user interface of their favorite email client. The Bridge is supported for three major email clients. For macOS: Thunderbird Apple Mail […]

Missing starred folder

In ProtonMail, users can star important emails to more easily find them or to remember to come back to them later. These emails can be found in the Starred folder of the ProtonMail app. The Bridge integrates the ProtonMail Starred folder with the corresponding folder in your desktop email client. […]