# Proton Mail Bridge

[Proton Mail Bridge](/content/mail/bridge/index.html) is an open-source application that allows you to fully integrate your Proton Mail account with any program that supports IMAP and SMTP. This includes Microsoft Outlook, Mozilla Thunderbird, and Apple Mail.  
It runs in the background on your computer and seamlessly encrypts and decrypts your mail as it enters and leaves your computer.

Before you configure Thunderbird to use Proton Mail, you must first [sign up for a Proton Mail plan](/content/mail/pricing/index.html) and [download and install Proton Mail Bridge](/content/mail/bridge#download/index.html) on your computer.

Once you’ve installed and added your account(s) to Proton Mail Bridge, you will need to configure your email client. Proton Mail Bridge works with most email clients and applications that support IMAP/SMTP connections.

In this guide, we provide step-by-step instructions to configure Mozilla Thunderbird to use with Proton Mail Bridge in Windows, macOS, and Linux.

## How to set up Mozilla Thunderbird with Proton Mail Bridge

Recent versions of Thunderbird include an experimental feature called Account Hub, which changes how new accounts are added. To follow the steps in this guide, we recommend disabling this feature:

Go to **Thunderbird** → **Menu** → **Settings** → **General**, scroll down to **Account Hub**, and uncheck **Create accounts in the new Account Hub**.

Here’s how to add Proton Mail to Thunderbird using Bridge:

1. Open Thunderbird, and click the hamburger **Menu** at the top right **→ New Account → Email**

2. Enter your **name**, **email address**, and **Proton Mail Bridge password**.  
   
   The name you enter in **Your full name** will be used as your display name. Make sure you enter the password displayed in the Bridge **Mailbox details** rather than your regular account password.

3. Click **Continue**, and the server settings should be detected automatically. You’ll see the message **Configuration found at email provider**.  
   
   If you’re using a custom domain, you’ll need to click on **Configure manually.**  
   
   Then enter the details from the Bridge **Mailbox Details** section manually.

4. Click **Done**, and you’ll be asked to confirm the exception for the security certificate. Since Proton Mail Bridge uses a certificate locally on your device, this can’t be signed by a certificate authority and requires you to confirm it manually.

5. Thunderbird will now be able to fetch your emails. To send emails, you’ll need to confirm the certificate for SMTP. To trigger this, send a test message. When you press **Send**, you’ll receive the same popup as above but for the SMTP port.  
   
   Once you confirm the exception, you might get an error message. You can dismiss it, then try to send the message again. It should work this time.

## Set up Mozilla Thunderbird to send from Proton Mail aliases

If you want to send from your alias addresses, you can add them to Thunderbird as follows:

1. Open Thunderbird and go to **Menu** → **Account Settings**.  
2. Select the account, and click **Manage Identities** at the bottom.
3. Click **Add** to add your email alias.
4. Enter the necessary details, such as **Name** and **Email Address**, and click **OK.**

If you want to add each address as a separate account to Thunderbird, you can use [split address mode](/content/support/difference-combined-addresses-mode-split-addresses-mode/index.html).

And you’re done! You can now use your Proton Mail account with Thunderbird to send and receive messages.