ProtonMail offers free end-to-end encrypted email service through a convenient web interface and mobile apps. Exporting emails or accessing them by any other means is a challenge, but the free version of ProtonMail offers more productivity features.
Information in this article applies to the web version of ProtonMail as well as the ProtonMail apps for iOS and Android.
ProtonMail Pros and Cons
Compared to similar services, ProtonMail provides several benefits and a few limitations.
What We Like
Easy and secure email encryption.
Multiple encryption options.
Set emails to expire after a certain date.
Access ProtonMail on any device with the mobile app.
What We Don’t Like
Occasionally sluggish web interface.
Limited search and organization features.
Cumbersome integration with other email clients.
Free vs. Premium ProtonMail
Anyone can sign up for ProtonMail and get 500 MB of online storage for free. Paid accounts include up to 20 GB of storage in addition to priority customer support and other productivity features. The free service should suffice if you occasionally send encrypted email.
What Is End-to-End Encryption?
Encryption protects the content of emails from prying eyes. As messages are sent from your computer to the recipients' inboxes, they can be intercepted by malicious third parties along the way.
With end-to-end encryption, the message is encrypted when you send it and is decrypted when the recipient opens it. Because the message can be unlocked only with the recipient’s personal key, nobody in between can decrypt it. Services like ProtonMail make it possible to transmit sensitive information without worrying about it falling into the wrong hands.
How ProtonMail Encrypts Email Messages
When you exchange emails with another ProtonMail user, messages are encrypted with their key in your browser or smartphone app and are deciphered when the recipient opens the message. Therefore, you don't have to set up passwords.
When you send a message to someone who does not use ProtonMail, you have the option to encrypt it with a password. The recipient will receive a message containing a link to the ProtonMail web interface, and they must enter the password to view your message. From that same interface, they can reply with an encrypted message protected by the same password.
You can also use PGP to encrypt messages and can export your public and private PGP keys from ProtonMail to use with a different service. Conversely, if you've been using encrypted email, you can import your existing keys to your ProtonMail account.
The ProtonMail Interface
The ProtonMail web interface includes folders found in other email clients (such as Archive and Spam). It includes color-coded labels, stars to make messages stand out, and rules to automatically label incoming mail. Paid ProtonMail users can create unlimited custom rules while free accounts are limited to one custom rule. It also has a simple auto-response feature.
Instead of entering @protonmail.com every time you enter your address, select pm.me on the ProtonMail interface to reduce it to a simple @pm.me.
Send Messages With ProtonMail
Use the ProtonMail rich-text editor to customize messages with HTML formatting and inline images. Although ProtonMail supports a few keyboard shortcuts, it offers limited help with composing messages. For example, you cannot set up templates or text snippets, and ProtonMail does not suggest text, times, or recipients.
ProtonMail's cryptography brings another benefit: You can set emails to self-destruct at a time you specify. For additional security, enable two-factor authentication.
Search for Messages in ProtonMail
ProtonMail has a search feature, but the fields that can be searched are restricted to information in the message headers such as sender, subject, and date. Encryption prevents ProtonMail from searching the body of a message, but if you set up the ProtonMail Bridge application on your desktop, you can expand searches to include the email contents.
How to Use ProtonMail With Your Other Email Accounts
ProtonMail Bridge is a desktop application that links your other email accounts with your ProtonMail account. Because of the way ProtonMail encrypts mail, it cannot connect directly with other email clients, so the Bridge acts as a remote server to facilitate communication. Any mail client that supports connecting to a remote mail server, such as Outlook and Thunderbird, can connect to ProtonMail this way.
ProtonMail cannot collect mail from your existing email accounts, and you cannot set it up to send mail using your existing email addresses. Nonetheless, using your favorite email program with ProtonMail might help with some of the productivity shortcomings.
ProtonMail Bridge is only available for paid subscribers.