Run ProtonMail Bridge in a docker container

Usage

Starting the service

initial setup

docker volume create proton-bridge
docker run --rm -v proton-bridge:/root -e PM_USER='<username>' -e PM_PASS='<password>' -e IMAP_PORT=143 -e SMTP_PORT=25 -p 25:25 -p 143:143 spameier/proton-bridge

later execution

docker run --rm -v proton-bridge:/root -e IMAP_PORT=143 -e SMTP_PORT=25 -p 25:25 -p 143:143 spameier/proton-bridge

Configuring your email client

For credentials, use the "Username: " and "Password: " that the service prints when it start.

The URL for the IMAP service is localhost:143, and the SMTP one is localhost:25.

Client compatibility

The ProtonMail Bridge officially supports Thunderbird only, but using offlineimap or fetchmail works just fine. Here's an example .fetchmailrc:

set daemon 15

defaults
  fetchall
#  keep

poll 127.0.0.1 service 2143 with protocol imap auth password
  user <login> there is seb here
  password <passwd>

SSL certificates

SMTP

Full certificate information:

echo | openssl s_client -connect localhost:2025 -starttls smtp | openssl x509 -noout -text

Fingerprints:

echo | openssl s_client -connect localhost:2025 -starttls smtp | openssl x509 -noout -fingerprint -md5
echo | openssl s_client -connect localhost:2025 -starttls smtp | openssl x509 -noout -fingerprint -sha1
echo | openssl s_client -connect localhost:2025 -starttls smtp | openssl x509 -noout -fingerprint -sha256
[...]

IMAP