Use Mailcow if you need a complete email server (send + receive + webmail + admin panel). Use Postal if you need an outbound sending platform with delivery tracking and webhooks (like self-hosted Postmark). Use Stalwart if you want a modern, Rust-based server with JMAP support and lower resource usage. All three are free, open-source, and run on $5-10/month VPS.
Mailcow vs Postal vs Stalwart: Which Self-Hosted Email Server?
For setup guides, see Mailcow, Postal, and Stalwart. For a VPS comparison, check our dedicated guide.
Three Different Tools for Three Different Needs
| Feature | Mailcow | Postal | Stalwart |
|---|---|---|---|
| Primary Use | Full email server | Outbound sending platform | Modern mail server |
| Send Email | Yes | Yes | Yes |
| Receive Email | Yes (IMAP/POP3) | Bounce processing only | Yes (JMAP/IMAP) |
| Webmail | Yes (SOGo) | No | No (use Roundcube) |
| Admin Panel | Yes (web UI) | Yes (web UI) | Yes (web UI) |
| Delivery Tracking | Basic (logs) | Yes (dashboard) | Basic (logs) |
| Webhooks | No | Yes | Limited |
| Multi-org Support | Multi-domain | Multi-organization | Multi-domain |
| Antispam | Rspamd | Basic | Built-in |
| Antivirus | ClamAV | No | No |
| Calendar/Contacts | SOGo (CalDAV/CardDAV) | No | No |
| Language | PHP/Python (Postfix) | Ruby | Rust |
| Min RAM | 2GB (4GB recommended) | 2GB | 512MB |
| Docker | Yes | Yes | Yes or standalone |
| Active Development | Very active | Active | Active |
| Community | Large | Medium | Growing |
Mailcow: The Complete Email Server
Best for: Businesses that need a full email server replacing Google Workspace or Microsoft 365. Send, receive, webmail, calendar, contacts, antispam — all in one Docker deployment.
Strengths:
- Most feature-complete self-hosted option
- Active community with frequent updates
- Web admin panel for managing domains, mailboxes, aliases
- SOGo webmail with calendar and contacts
- Rspamd antispam + ClamAV antivirus included
- Excellent documentation
Weaknesses:
- Resource-heavy (15+ containers, needs 2-4GB RAM)
- No delivery tracking dashboard (check logs manually)
- No webhook support for bounce/complaint processing
- Overkill if you only need outbound sending
Setup: Complete Mailcow guide
Postal: The Sending Platform
Best for: Outbound email sending with delivery tracking. Like self-hosted Postmark or SendGrid. Ideal for GoHighLevel SMTP, application email, and agencies managing multiple clients.
Strengths:
- Web dashboard showing delivery status, opens, clicks, bounces
- Webhook events for automated bounce/complaint processing
- Multi-organization support (perfect for agencies)
- IP pool management
- Message retention for debugging
Weaknesses:
- Outbound only — no incoming email (IMAP/POP3)
- No webmail
- No antispam (not needed for outbound)
- Less active community than Mailcow
Setup: Complete Postal guide
Stalwart: The Modern Option
Best for: Technically-minded users who want a modern, efficient mail server written in Rust with JMAP support.
Strengths:
- Written in Rust — fast, memory-efficient, secure
- JMAP support (modern protocol, faster than IMAP)
- Runs on minimal resources (512MB RAM)
- Active development with modern architecture
- Integrated spam filter
Weaknesses:
- Newer project, less battle-tested
- Smaller community, less documentation
- No built-in webmail (pair with Roundcube)
- Less plug-and-play than Mailcow
Decision Guide
| Your Need | Choose |
|---|---|
| Full email server (replace Gmail) | Mailcow |
| Outbound sending platform (replace Mailgun) | Postal |
| Modern, lightweight mail server | Stalwart |
| GoHighLevel SMTP | Postal (best tracking) or Mailcow (if also need receiving) |
| Agency managing 10+ client domains | Postal (multi-org support) |
| Minimum resource usage | Stalwart (512MB RAM) |
| Easiest setup | Mailcow (best docs) |
The Hybrid Approach
You can run multiple:
- Postal for outbound sending (GoHighLevel, applications)
- Mailcow for employee email (inbox, calendar, contacts)
Both on the same VPS or separate servers. This gives you the best of both worlds.
Practitioner note: For GoHighLevel agencies, I recommend Postal over Mailcow. The delivery tracking dashboard alone is worth it — you can see exactly what happened to every email GHL sent through your infrastructure. With Mailcow, you're reading raw logs.
Practitioner note: Stalwart is the one to watch. The Rust foundation means it's faster and uses less memory than anything else available. As the community grows and documentation improves, it may become the default recommendation. For now, Mailcow and Postal are safer choices for production.
If you want a self-hosted email server deployed and configured, schedule a consultation — I'll recommend the right option and handle the setup.
Sources
- Mailcow: docs.mailcow.email
- Postal: docs.postalserver.io
- Stalwart: stalw.art
v1.0 · March 2026
Frequently Asked Questions
Which is easiest to set up?
Mailcow. Docker-based, well-documented, active community. Generate config, docker compose up, done. Postal requires more manual configuration. Stalwart is newer with less community documentation.
Which uses the least resources?
Stalwart. Written in Rust, it's significantly lighter than Mailcow (which runs 15+ Docker containers including ClamAV, Rspamd, SOGo, etc.). Stalwart can run on 512MB RAM. Mailcow needs 2GB+ minimum.
Which is best for GoHighLevel?
Postal. Its SMTP relay capabilities and delivery tracking dashboard make it ideal for GHL integration. You get delivery logs, bounce tracking, and multi-organization support — all features that GHL lacks with custom SMTP.
Can any of these replace Gmail/Outlook for daily email?
Mailcow: yes, includes SOGo webmail, IMAP, CalDAV/CardDAV. Postal: no, outbound only. Stalwart: partially, has JMAP/IMAP but no built-in webmail. For full email server replacing Gmail, Mailcow is the choice.
Which has the best deliverability?
All three deliver comparably when properly configured with SPF, DKIM, DMARC, and clean IPs. Deliverability is determined by your configuration and reputation, not the software. The difference is in monitoring: Postal provides the best delivery tracking dashboard.
Want this handled for you?
Free 30-minute strategy call. Walk away with a plan either way.