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

Why Self-Host Roundcube?

The case for self-hosting Roundcube comes down to three practical factors: data ownership, cost at scale, and operational control.

Data ownership is the fundamental argument. When you use a SaaS version of any tool, your data lives on someone else's infrastructure subject to their terms of service, their security practices, and their business continuity. If the vendor raises prices, gets acquired, changes API limits, or shuts down, you're left scrambling. Self-hosting Roundcube means your data and configuration stay on infrastructure you control — whether that's a VPS, a bare metal server, or a home lab.

Cost at scale matters once you move beyond individual use. Most SaaS equivalents charge per user or per data volume. A self-hosted instance on a $10-20/month VPS typically costs less than per-user SaaS pricing for teams of five or more — and the cost doesn't scale linearly with usage. One well-configured server handles dozens of users for a flat monthly fee.

Operational control is the third factor. The Docker Compose configuration above exposes every setting that commercial equivalents often hide behind enterprise plans: custom networking, environment variables, storage backends, and authentication integrations. You decide when to update, how to configure backups, and what access controls to apply.

The honest tradeoff: you're responsible for updates, backups, and availability. For teams running any production workloads, this is familiar territory. For individuals, the learning curve is real but the tooling (Docker, Caddy, automated backups) is well-documented and widely supported.

Server Requirements and Sizing

Before deploying Roundcube, assess your server capacity against expected workload.

Minimum viable setup: A 1 vCPU, 1GB RAM VPS with 20GB SSD is sufficient for personal use or small teams. Most consumer VPS providers — Hetzner, DigitalOcean, Linode, Vultr — offer machines in this range for $5-10/month. Hetzner offers excellent price-to-performance for European and US regions.

Recommended production setup: 2 vCPUs with 4GB RAM and 40GB SSD handles most medium deployments without resource contention. This gives Roundcube headroom for background tasks, caching, and concurrent users while leaving capacity for other services on the same host.

Storage planning: The Docker volumes in this docker-compose.yml store all persistent Roundcube data. Estimate your storage growth rate early — for data-intensive tools, budget for 3-5x your initial estimate. Hetzner Cloud and Vultr both support online volume resizing without stopping your instance.

Operating system: Any modern 64-bit Linux distribution works. Ubuntu 22.04 LTS and Debian 12 are the most commonly tested configurations. Ensure Docker Engine 24.0+ and Docker Compose v2 are installed — verify with docker --version and docker compose version. Avoid Docker Desktop on production Linux servers; it adds virtualization overhead and behaves differently from Docker Engine in ways that cause subtle networking issues.

Network: Only ports 80 and 443 need to be publicly accessible when running behind a reverse proxy. Internal service ports should be bound to localhost only. A minimal UFW firewall that blocks all inbound traffic except SSH, HTTP, and HTTPS is the single most effective security measure for a self-hosted server.

Backup and Disaster Recovery

Running Roundcube without a tested backup strategy is an unacceptable availability risk. Docker volumes are not automatically backed up — if you delete a volume or the host fails, data is gone with no recovery path.

What to back up: The named Docker volumes containing Roundcube's data (database files, user uploads, application state), your docker-compose.yml and any customized configuration files, and .env files containing secrets.

Backup approach: For simple setups, stop the container, archive the volume contents, then restart. For production environments where stopping causes disruption, use filesystem snapshots or database dump commands (PostgreSQL pg_dump, SQLite .backup, MySQL mysqldump) that produce consistent backups without downtime.

For a complete automated backup workflow that ships snapshots to S3-compatible object storage, see the Restic + Rclone backup guide. Restic handles deduplication and encryption; Rclone handles multi-destination uploads. The same setup works for any Docker volume.

Backup cadence: Daily backups to remote storage are a reasonable baseline for actively used tools. Use a 30-day retention window minimum — long enough to recover from mistakes discovered weeks later. For critical data, extend to 90 days and use a secondary destination.

Restore testing: A backup that has never been restored is a backup you cannot trust. Once a month, restore your Roundcube backup to a separate Docker Compose stack on different ports and verify the data is intact. This catches silent backup failures, script errors, and volume permission issues before they matter in a real recovery.

Security Hardening

Self-hosting means you are responsible for Roundcube's security posture. The Docker Compose setup provides a functional base; production deployments need additional hardening.

Always use a reverse proxy: Never expose Roundcube's internal port directly to the internet. The docker-compose.yml binds to localhost; Caddy or Nginx provides HTTPS termination. Direct HTTP access transmits credentials in plaintext. A reverse proxy also centralizes TLS management, rate limiting, and access logging.

Strong credentials: Change default passwords immediately after first login. For secrets in docker-compose environment variables, generate random values with openssl rand -base64 32 rather than reusing existing passwords.

Firewall configuration:

ufw default deny incoming
ufw allow 22/tcp
ufw allow 80/tcp
ufw allow 443/tcp
ufw enable

Internal service ports (databases, admin panels, internal APIs) should only be reachable from localhost or the Docker network, never directly from the internet.

Network isolation: Docker Compose named networks keep Roundcube's services isolated from other containers on the same host. Database containers should not share networks with containers that don't need direct database access.

VPN access for sensitive services: For internal-only tools, restricting access to a VPN adds a strong second layer. Headscale is an open source Tailscale control server that puts your self-hosted stack behind a WireGuard mesh, eliminating public internet exposure for internal tools.

Update discipline: Subscribe to Roundcube's GitHub releases page to receive security advisory notifications. Schedule a monthly maintenance window to pull updated images. Running outdated container images is the most common cause of self-hosted service compromises.

Troubleshooting Common Issues

Container exits immediately or won't start

Check logs first — they almost always explain the failure:

docker compose logs -f roundcube

Common causes: a missing required environment variable, a port already in use, or a volume permission error. Port conflicts appear as bind: address already in use. Find the conflicting process with ss -tlpn | grep PORT and either stop it or change Roundcube's port mapping in docker-compose.yml.

Cannot reach the web interface

Work through this checklist:

Confirm the container is running: docker compose ps
Test locally on the server: curl -I http://localhost:PORT
If local access works but external doesn't, check your firewall: ufw status
If using a reverse proxy, verify it's running and the config is valid: caddy validate --config /etc/caddy/Caddyfile

Permission errors on volume mounts

Some containers run as a non-root user. If the Docker volume is owned by root, the container process cannot write to it. Find the volume's host path with docker volume inspect VOLUME_NAME, check the tool's documentation for its expected UID, and apply correct ownership:

chown -R 1000:1000 /var/lib/docker/volumes/your_volume/_data

High resource usage over time

Memory or CPU growing continuously usually indicates unconfigured log rotation, an unbound cache, or accumulated data needing pruning. Check current usage with docker stats roundcube. Add resource limits in docker-compose.yml to prevent one container from starving others. For ongoing visibility into resource trends, deploy Prometheus + Grafana or Netdata.

Data disappears after container restart

Data stored in the container's writable layer — rather than a named volume — is lost when the container is removed or recreated. This happens when the volume mount path in docker-compose.yml doesn't match where the application writes data. Verify mount paths against the tool's documentation and correct the mapping. Named volumes persist across container removal; only docker compose down -v deletes them.

Keeping Roundcube Updated

Roundcube follows a regular release cadence. Staying current matters for security patches and compatibility. The update process with Docker Compose is straightforward:

docker compose pull          # Download updated images
docker compose up -d         # Restart with new images
docker image prune -f        # Remove old image layers (optional)

Read the changelog before major version updates. Some releases include database migrations or breaking configuration changes. For major version bumps, test in a staging environment first — run a copy of the service on different ports with the same volume data to validate the migration before touching production.

Version pinning: For stability, pin to a specific image tag in docker-compose.yml instead of latest. Update deliberately after reviewing the changelog. This trades automatic patch delivery for predictable behavior — the right call for business-critical services.

Post-update verification: After updating, confirm Roundcube is functioning correctly. Most services expose a /health endpoint that returns HTTP 200 — curl it from the server or monitor it with your uptime tool.

Frequently Asked Questions

How much does it cost to self-host Roundcube?

The primary cost is your server. A Hetzner CAX11 (2 vCPU ARM, 4GB RAM) runs about $5/month — enough for Roundcube plus a few companion services. Add a domain ($12/year) and you're under $75/year for a complete self-hosted deployment. Compare that to SaaS pricing that typically starts at $5-15/user/month.

Can I run Roundcube on a VPS with other services?

Yes. The docker-compose.yml above isolates Roundcube on its own named Docker network. As long as your server has sufficient RAM and disk — 4GB RAM and 20GB disk handles most combinations — running multiple self-hosted services on one VPS is both practical and common. Tools like Dozzle and Portainer make monitoring multi-container setups manageable.

How do I migrate data if I switch servers?

Stop the Roundcube container, export the Docker volumes (using docker run --rm -v VOLUME:/data -v $(pwd):/backup alpine tar czf /backup/backup.tar.gz /data), transfer to the new server, restore the volumes, and update your DNS. Most migrations complete in under an hour. Test the restoration on the new server before decommissioning the old one.

What happens if Roundcube releases a breaking update?

Pin your docker-compose.yml to a specific image tag (e.g., image: roundcube:1.2.3 instead of latest). Subscribe to the GitHub releases page for advance notice. When you're ready to upgrade, read the release notes, back up first, test on a staging instance, then update production.

Is Roundcube suitable for production use?

Yes, with the hardening described above: reverse proxy for HTTPS, firewall rules, regular backups, and a pinned image tag. Many teams run Roundcube in production successfully. The main requirement is treating your self-hosted instance with the same operational discipline you'd apply to any business-critical service.

See our email server guides: Mailcow, Stalwart

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

The SaaS-to-Self-Hosted Migration Guide (Free PDF)