How to Self-Host Roundcube: Open Source Webmail 2026

TL;DR

Roundcube (GPL 3.0, ~5K GitHub stars, PHP) is the most widely deployed open source webmail client — it powers the webmail interface for millions of hosting providers worldwide. Unlike SOGo (used in Mailcow) which targets enterprise, Roundcube is lean and focused: fast IMAP webmail with a clean UI, PGP encryption via Enigma plugin, CardDAV contacts via plugin, and a responsive "Elastic" skin that works on mobile. If you run your own mail server (Mailcow, Stalwart, Postfix+Dovecot) and want a webmail UI, Roundcube is the go-to option.

Key Takeaways

Roundcube: GPL 3.0, ~5K stars, PHP — most widely deployed open source webmail
IMAP-only: Roundcube connects to any IMAP server — not tied to a specific mail backend
Elastic skin: Modern responsive skin that works well on mobile
Enigma plugin: PGP email encryption/decryption built-in
Plugin ecosystem: CardDAV contacts, 2FA, HTML signatures, calendar preview, and more
vs SOGo: Roundcube is simpler, faster, and easier to theme; SOGo includes calendar/contacts natively

Part 1: Docker Setup

# docker-compose.yml
services:
  roundcube:
    image: roundcube/roundcubemail:latest
    container_name: roundcube
    restart: unless-stopped
    ports:
      - "9090:80"
    volumes:
      - roundcube_config:/var/roundcube/config
      - roundcube_db:/var/roundcube/db
      - roundcube_temp:/tmp/roundcube-temp
      - roundcube_logs:/var/log/roundcube
    environment:
      # IMAP server (your mail server):
      ROUNDCUBEMAIL_DEFAULT_HOST: "tls://mail.yourdomain.com"
      ROUNDCUBEMAIL_DEFAULT_PORT: 993

      # SMTP server for sending:
      ROUNDCUBEMAIL_SMTP_SERVER: "tls://mail.yourdomain.com"
      ROUNDCUBEMAIL_SMTP_PORT: 587

      # Database (SQLite for simple setup):
      ROUNDCUBEMAIL_DB_TYPE: sqlite

      # Session security:
      ROUNDCUBEMAIL_DES_KEY: "rcdeskeyrandomchange"  # 24 chars

      # UI settings:
      ROUNDCUBEMAIL_SKIN: elastic
      ROUNDCUBEMAIL_LANGUAGE: en_US

      # Upload size limit:
      ROUNDCUBEMAIL_UPLOAD_MAX_FILESIZE: 25M

      # Enable plugins:
      ROUNDCUBEMAIL_PLUGINS: "archive,zipdownload,carddav,enigma"

volumes:
  roundcube_config:
  roundcube_db:
  roundcube_temp:
  roundcube_logs:

docker compose up -d

Visit http://your-server:9090 (or via Caddy at https://mail.yourdomain.com/webmail).

Part 2: HTTPS with Caddy

Standalone webmail subdomain

webmail.yourdomain.com {
    reverse_proxy localhost:9090
}

Subpath under existing domain

mail.yourdomain.com {
    # Admin UI:
    handle /admin* {
        reverse_proxy localhost:8080
    }

    # Webmail:
    handle /webmail* {
        uri strip_prefix /webmail
        reverse_proxy localhost:9090
    }

    # Default → webmail:
    handle {
        reverse_proxy localhost:9090
    }
}

Part 3: PostgreSQL for Production

Switch from SQLite to PostgreSQL for better performance with multiple users:

services:
  roundcube:
    image: roundcube/roundcubemail:latest
    environment:
      ROUNDCUBEMAIL_DB_TYPE: pgsql
      ROUNDCUBEMAIL_DB_HOST: db
      ROUNDCUBEMAIL_DB_PORT: 5432
      ROUNDCUBEMAIL_DB_USER: roundcube
      ROUNDCUBEMAIL_DB_PASSWORD: "${DB_PASSWORD}"
      ROUNDCUBEMAIL_DB_NAME: roundcube
    depends_on:
      db:
        condition: service_healthy

  db:
    image: postgres:16-alpine
    restart: unless-stopped
    environment:
      POSTGRES_DB: roundcube
      POSTGRES_USER: roundcube
      POSTGRES_PASSWORD: "${DB_PASSWORD}"
    volumes:
      - db_data:/var/lib/postgresql/data
    healthcheck:
      test: ["CMD-SHELL", "pg_isready -U roundcube"]
      interval: 10s
      start_period: 20s

volumes:
  db_data:

Part 4: Plugins

CardDAV Contacts (roundcube-carddav)

Sync contacts from any CardDAV server (Nextcloud, Baikal, Radicale):

# Add plugin to Roundcube config:
# The carddav plugin is included in the Docker image via ROUNDCUBEMAIL_PLUGINS env var.

# Users configure their CardDAV sources in:
# Settings → Contacts → Add address book

Enigma (PGP Encryption)

Enable PGP email encryption:

environment:
  ROUNDCUBEMAIL_PLUGINS: "archive,zipdownload,enigma"

Users import their PGP key in Settings → Encryption. Outgoing emails to contacts with known public keys are automatically encrypted.

Two-Factor Authentication (2FA)

# Install via plugin manager or docker build:
# Popular plugin: roundcube/two_factor_auth

# Add to custom Docker image:
FROM roundcube/roundcubemail:latest
RUN git clone https://github.com/alexandregz/twofactor_gauthenticator.git \
    /var/www/html/plugins/twofactor_gauthenticator

Part 5: Configuration File

For advanced configuration beyond environment variables:

<?php
// /var/roundcube/config/config.inc.php (mounted volume)

// Session lifetime (minutes):
$config['session_lifetime'] = 10;

// Max login attempts before lockout:
$config['login_rate_limit'] = 3;

// Show only this domain in username field:
$config['username_domain'] = 'yourdomain.com';
// With this set, users log in as "hello" instead of "hello@yourdomain.com"

// Default folders:
$config['drafts_mbox'] = 'Drafts';
$config['sent_mbox'] = 'Sent';
$config['trash_mbox'] = 'Trash';
$config['junk_mbox'] = 'Junk';

// Preview pane enabled by default:
$config['preview_pane'] = true;

// HTML email on by default:
$config['htmleditor'] = 1;

// Auto-save drafts every N seconds:
$config['draft_autosave'] = 300;

// Spell check (aspell required in image):
$config['enable_spellcheck'] = true;
$config['spellcheck_engine'] = 'aspell';

// Max email size:
$config['max_message_size'] = '25M';

// SMTP authentication type:
$config['smtp_auth_type'] = 'PLAIN';

// Hide other users' folders on shared IMAP:
$config['show_other_folders'] = false;

// Vacation auto-reply via Sieve:
$config['managesieve_host'] = 'tls://mail.yourdomain.com';
$config['managesieve_port'] = 4190;

Part 6: Skins and Themes

Roundcube ships with two skins:

Skin	Description
elastic	Modern, responsive — works on mobile (recommended)
larry	Classic three-pane layout (legacy)

Custom skin

# Download a community skin:
git clone https://github.com/example/roundcube-skin-custom.git \
  /var/roundcube/skins/custom

# Set as default:
echo "\$config['skin'] = 'custom';" >> /var/roundcube/config/config.inc.php

Custom logo

// Replace the Roundcube logo with your own:
$config['product_name'] = 'YourDomain Mail';
$config['skin_logo'] = '/path/to/logo.png';

Part 7: Integration with Mailcow

Mailcow ships SOGo as webmail by default, but you can add Roundcube alongside it:

# Add to mailcow-dockerized docker-compose.override.yml:
services:
  roundcube:
    image: roundcube/roundcubemail:latest
    restart: unless-stopped
    ports:
      - "127.0.0.1:9090:80"
    environment:
      ROUNDCUBEMAIL_DEFAULT_HOST: dovecot
      ROUNDCUBEMAIL_DEFAULT_PORT: 993
      ROUNDCUBEMAIL_SMTP_SERVER: postfix
      ROUNDCUBEMAIL_SMTP_PORT: 587
      ROUNDCUBEMAIL_DB_TYPE: sqlite
      ROUNDCUBEMAIL_SKIN: elastic
    networks:
      - mailcow-network

networks:
  mailcow-network:
    external: true
    name: mailcow-dockerized_mailcow-network

# Add to mailcow Nginx config (mailcow.conf):
location /webmail {
    proxy_pass http://roundcube:80;
}

Part 8: Vacation Auto-Reply and Filters

With ManageSieve enabled (port 4190 on Stalwart/Dovecot):

// config.inc.php:
$config['managesieve_host'] = 'tls://mail.yourdomain.com';
$config['managesieve_port'] = 4190;
$config['managesieve_usetls'] = true;

Users then get in Settings:

Filters — create mail filtering rules (move to folders, auto-respond, etc.)
Vacation — set auto-reply with start/end dates

Maintenance

# Update Roundcube:
docker compose pull
docker compose up -d

# Cleanup old sessions (run weekly):
docker exec roundcube php /var/www/html/bin/cleandb.sh

# Backup:
# SQLite:
docker cp roundcube:/var/roundcube/db/sqlite.db ./roundcube-backup-$(date +%Y%m%d).db

# PostgreSQL:
docker exec roundcube-db-1 pg_dump -U roundcube roundcube \
  | gzip > roundcube-db-$(date +%Y%m%d).sql.gz

# Logs:
docker compose logs -f roundcube

See our email server guides: Mailcow, Stalwart

See all open source email tools at OSSAlt.com/categories/email.

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