Protonmail Bridge for Mobile Devices

This post will go over setting up a bridge to use Protonmail with other devices that don’t have the official Protonmail Bridge available for them. The Protonmail Bridge allows you to get all the benefits of Protonmail with other mail clients.

I’m writing this because I think Protonmail’s mobile client kind of sucks and because Apple announced some pretty nice privacy features coming in i[Pad]OS 15 that I would love to take advantage of. Plus, I wouldn’t mind having one less app on my phone.


  • A Linux server to host the bridge
  • Docker installed on your Linux host

I’m gonna assume you have a Linux server setup that you’d like to dedicate to the bridge. I’d recommend setting up Wireguard or some sort of VPN to encrypt the connection between your client and the server and as a way to restrict access to the bridge.

Setup the Bridge:

I’m going to use hydroxide, an open source Protonmail bridge for making Protonmail accessible to my other devices.

I created a cross-architecture Docker image to simplify this process greatly for myself and others.

First, install Docker on your host:

Get Docker

For the rest of the post I’ll assume that the following Docker commands will be run as root or as a user who can access the Docker daemon. Alternatively, I would suggest looking into rootless Docker and running the hydroxide container as an unprivileged user. Regardless, just make sure you’re at a place where you can run docker commands without an issue.

Now, let’s login to Protonmail with hydroxide:

mkdir -p ~/.config/hydroxide

docker run -it --rm -v ~/.config/hydroxide:/root/.config/hydroxide heywoodlh/hydroxide auth <user>

Now run the following command to run Hydroxide’s IMAP, SMTP and CalDav instance (modify to match whatever IP address your devices will be connecting to):

docker run --restart unless-stopped -p 1025:1025 -p 1143:1143 -p 8080:8080 -d -v ~/.config/hydroxide:/root/.config/hydroxide --name hydroxide heywoodlh/hydroxide -imap-host -smtp-host -carddav-host serve

Check if your container is running:

docker logs hydroxide

Connect Your Client:

Now all you have to do is connect your app to your Hydroxide instance using the following settings:

IMAP: hydroxide-host:1143

SMTP: hydroxide-host:1025

CardDAV: hydroxide-host:8080

Note on iOS:

Using an alternate port for SMTP and IMAP isn’t well documented so I wanted to throw in that I followed this post to set up Apple Mail on my iPhone and iPad with a custom port for SMTP/IMAP:

Change Mail Server ports Apple iPhone X, XS, XR, 11, 11 Pro, 11 Max and iOS 12 and 13 up

Written on June 10, 2021