What are the ProtonMail SMTP settings?

ProtonMail requires Bridge app. SMTP server is 127.0.0.1 (localhost), port 1025. Credentials are generated by Bridge.

Can I use ProtonMail SMTP without Bridge?

No, ProtonMail does not offer direct SMTP access. You must use Proton Mail Bridge which runs locally on your computer.

update Updated January 2026 lock Privacy-Focused

ProtonMail SMTP Settings

Configure ProtonMail for sending emails via SMTP using Proton Mail Bridge. End-to-end encrypted email service based in Switzerland.

warning

Proton Mail Bridge Required

ProtonMail does not offer direct SMTP access. You must install and run Proton Mail Bridge on your local computer. Bridge is available only for paid ProtonMail accounts.

table_chart Quick Reference (via Bridge)

Setting	Value
SMTP Server	`127.0.0.1` (localhost)
Port (STARTTLS)	`1025`
IMAP Port	`1143`
Username	Your ProtonMail email address
Password	Bridge-generated password
Encryption	STARTTLS
Required Plan	Paid plan (Mail Plus or higher)

How Proton Mail Bridge Works

Proton Mail Bridge runs locally on your computer and acts as a translator between your email client and ProtonMail's encrypted servers.

Your app connects to Bridge on localhost
Bridge encrypts the email with your ProtonMail key
Bridge sends encrypted email to ProtonMail servers
End-to-end encryption is preserved

security

End-to-end encryption maintained

Step-by-Step Setup Guide

Download Proton Mail Bridge

Download Bridge from proton.me/mail/bridge:

Available for Windows, macOS, and Linux
Requires a paid ProtonMail account
Install and launch the application

Sign In to Bridge

Open Proton Mail Bridge
Click 'Add account'
Enter your ProtonMail email and password
Complete 2FA if enabled

Get Bridge Credentials

Bridge generates unique SMTP credentials:

Click on your account in Bridge
Select 'Mailbox configuration'
Copy the generated password
Note the SMTP settings shown

info

This password is different from your ProtonMail account password!

Configure Your Application

Use these settings (Bridge must be running):

Server: 127.0.0.1
Port: 1025
Security: STARTTLS
Username: Your ProtonMail email
Password: Bridge-generated password

Code Examples

import smtplib
from email.mime.text import MIMEText
from email.mime.multipart import MIMEMultipart

# ProtonMail Bridge settings (Bridge must be running!)
SMTP_HOST = "127.0.0.1"
SMTP_PORT = 1025
SMTP_USER = "your-email@protonmail.com"
SMTP_PASS = "bridge-generated-password"

# Create message
msg = MIMEMultipart()
msg['From'] = SMTP_USER
msg['To'] = "recipient@example.com"
msg['Subject'] = "Test Email via ProtonMail"

body = "This is a test email sent via ProtonMail Bridge."
msg.attach(MIMEText(body, 'plain'))

# Send email via Bridge
with smtplib.SMTP(SMTP_HOST, SMTP_PORT) as server:
    server.starttls()
    server.login(SMTP_USER, SMTP_PASS)
    server.send_message(msg)
    print("Email sent successfully!")

<?php
use PHPMailer\PHPMailer\PHPMailer;

require 'vendor/autoload.php';

$mail = new PHPMailer(true);

// ProtonMail Bridge configuration
$mail->isSMTP();
$mail->Host       = '127.0.0.1';
$mail->SMTPAuth   = true;
$mail->Username   = 'your-email@protonmail.com';
$mail->Password   = 'bridge-generated-password';
$mail->SMTPSecure = PHPMailer::ENCRYPTION_STARTTLS;
$mail->Port       = 1025;

// Email content
$mail->setFrom('your-email@protonmail.com');
$mail->addAddress('recipient@example.com');
$mail->Subject = 'Test Email via ProtonMail';
$mail->Body    = 'This is a test email.';

$mail->send();
echo 'Email sent successfully!';

const nodemailer = require('nodemailer');

// Create ProtonMail Bridge transporter
const transporter = nodemailer.createTransport({
    host: '127.0.0.1',
    port: 1025,
    secure: false,  // STARTTLS
    auth: {
        user: 'your-email@protonmail.com',
        pass: 'bridge-generated-password'
    },
    tls: {
        rejectUnauthorized: false  // For self-signed Bridge cert
    }
});

// Send email
async function sendEmail() {
    const info = await transporter.sendMail({
        from: 'your-email@protonmail.com',
        to: 'recipient@example.com',
        subject: 'Test Email via ProtonMail',
        text: 'This is a test email.'
    });
    console.log('Email sent:', info.messageId);
}

sendEmail().catch(console.error);

Limitations

close Not Suitable For

Server-side applications
Cloud/headless environments
High-volume sending
Web applications without local access

check Works Well For

Desktop email clients
Local development
Personal automation scripts
Privacy-sensitive communications

Frequently Asked Questions

Can I use ProtonMail SMTP on a server?

Not easily. Bridge requires a desktop environment. For servers, consider using a different email provider for sending.

Is Bridge free?

Bridge itself is free, but it requires a paid ProtonMail account (Mail Plus, Proton Unlimited, or Business plan).

Why does ProtonMail require Bridge?

ProtonMail uses end-to-end encryption. Bridge handles the encryption/decryption locally so your emails remain secure while being compatible with standard email protocols.

Scripts

Parsers

Validators

SMTP Settings

SMTP Errors

Server Limits