Self-Hosted Email in 2025: Stalwart vs Mailcow vs iRedMail

The Self-Hosted Email Dilemma

Self-hosting email is the hardest self-hosting challenge. Unlike a web server or database, email requires perfect DNS configuration, IP reputation management, and constant vigilance against spam blacklists. But for organizations that need data sovereignty or custom email handling, it is worth it.

The Contenders

Stalwart Mail Server

Stalwart is the new generation — a single Rust binary that handles SMTP, IMAP, JMAP, and web admin. It is fast, memory-efficient, and modern.

services:
  stalwart:
    image: stalwartlabs/mail-server:latest
    container_name: stalwart
    volumes:
      - stalwart_data:/opt/stalwart-mail
    ports:
      - "25:25"      # SMTP
      - "465:465"    # SMTPS
      - "587:587"    # Submission
      - "993:993"    # IMAPS
      - "4190:4190"  # ManageSieve
      - "8080:8080"  # Web admin
    restart: unless-stopped

volumes:
  stalwart_data:

RAM: ~50MB idle, ~200MB under load.
Disk: Single binary, ~30MB.
Protocols: SMTP, IMAP, JMAP, ManageSieve, web admin.

Mailcow

Mailcow is the full-stack solution. It bundles Postfix, Dovecot, SOGo webmail, ClamAV antivirus, Rspamd spam filter, and a web admin — all orchestrated with Docker Compose.

# Install Mailcow
git clone https://github.com/mailcow/mailcow-dockerized
cd mailcow-dockerized
./generate_config.sh
docker compose pull
docker compose up -d

RAM: ~2GB minimum (ClamAV alone uses ~1GB).
Disk: ~5GB for all containers.
Components: 15+ Docker containers.
Protocols: SMTP, IMAP, POP3, CalDAV, CardDAV, webmail.

iRedMail

iRedMail is the traditional installer — it configures Postfix, Dovecot, Amavis, SpamAssassin, and Roundcube directly on a bare metal server or VM.

# Install iRedMail
wget https://github.com/iredmail/iRedMail/archive/1.7.1.tar.gz
tar xzf 1.7.1.tar.gz
cd iRedMail-1.7.1
bash iRedMail.sh

RAM: ~500MB (no ClamAV) to ~1.5GB (with ClamAV).
Disk: ~1GB installed.
Components: Postfix + Dovecot + SpamAssassin + Roundcube.

Comparison

DNS Configuration (Required for All)

Regardless of which solution you choose, you need these DNS records:

# MX Record
example.com.    MX    10    mail.example.com.

# A Record for mail server
mail.example.com.    A    YOUR_SERVER_IP

# SPF — who can send email for your domain
example.com.    TXT    "v=spf1 mx a ip4:YOUR_SERVER_IP -all"

# DKIM — cryptographic signature
default._domainkey.example.com.    TXT    "v=DKIM1; k=rsa; p=YOUR_PUBLIC_KEY..."

# DMARC — policy for failed authentication
_dmarc.example.com.    TXT    "v=DMARC1; p=reject; rua=mailto:[email protected]"

# Reverse DNS (PTR) — set via your hosting provider
YOUR_SERVER_IP    PTR    mail.example.com.

Testing Deliverability

# Test with mail-tester.com
echo "Test email from self-hosted server" | \
  mail -s "Deliverability Test" [email protected]

# Check MX records
dig MX example.com

# Check SPF
dig TXT example.com

# Check DKIM
dig TXT default._domainkey.example.com

# Check DMARC
dig TXT _dmarc.example.com

IP Reputation

The hardest part of self-hosted email is IP reputation. New IP addresses are often untrusted:

1. Use a clean IP: Check your IP on mxtoolbox.com/blacklists
2. Warm up slowly: Start with low volume, increase gradually over weeks
3. Monitor blacklists: Set up alerts for your IP on major blacklists
4. Use a relay for critical email: Route transactional email through a service like Amazon SES while using self-hosted for internal email

Our Recommendation

• Stalwart: Best for teams that want a modern, lightweight mail server and will use external clients (Thunderbird, Apple Mail). Lowest resource usage.
• Mailcow: Best for organizations that need a complete groupware solution with webmail, calendars, and contacts. Higher resource usage but everything included.
• iRedMail: Best for traditional sysadmins who want Postfix/Dovecot with a guided installation. Non-Docker deployments.

The Honest Truth About Self-Hosted Email

Self-hosted email works well for:

• Internal/team communication
• Receiving email (incoming works great)
• Organizations with clean IPs and dedicated sysadmins

Self-hosted email is painful for:

• Cold outreach / marketing email
• Small teams without email expertise
• Servers on residential IPs

At TechSaaS, we use a hybrid approach: self-hosted Stalwart for internal communication and receiving, with a transactional email service (like Listmonk + SMTP relay) for outbound delivery. This gives us data sovereignty without deliverability headaches.

Need help with email infrastructure? Contact [email protected].