Postmark vs Mailcow
A detailed comparison to help you choose between Postmark and Mailcow.
Quick Verdict
4.2/5
Postmark
0 reviews
4.1/5
Mailcow
0 reviews
Postmark is rated higher (4.2 vs 4.1). Postmark is a transactional email service with best-in-class inbox delivery rates. Focuses solely on transactional email (not marketing). Detailed bounce analytics, message streams, and server-side DKIM. Mailcow is a free, open source email server suite running on Docker. Complete mail server with anti-spam, anti-virus, webmail, SOGo, and admin panel. Self-host on any VPS.
Postmark Fastest transactional email delivery — inbox-focused | Mailcow Self-hosted email server with Docker | |
|---|---|---|
| Overview | ||
| Rating | 4.2 (0 reviews)✓ | 4.1 (0 reviews) |
| Pricing model | freemium | free |
| Starting price | Free tier available | Free |
| Best for | SaaS developers who need dependable delivery for password resets, receipts, and notifications, with the analytics to prove it landed | Sysadmins and small organisations who want self-hosted, sovereign email on their own server with full groupware, and who can operate a Docker-based mail stack |
| Specifications (entry plan) | ||
| CPU cores | — | 1 vCPU |
| RAM | — | 6 GB |
| Storage | — | 20 GB |
| Bandwidth | — | — |
| SLA uptime | — | — |
| Data-center count | — | — |
| €/vCPU/mo | — | €0.00 |
| €/GB RAM/mo | — | €0.00 |
| Features | ||
| IPv6 | ||
| DDoS protection | ||
| Automated backups | ||
| Snapshots | ||
| Managed option | ||
| Bare metal | ||
| GPU available | ||
| S3-compatible | ||
| Hourly billing | ||
| Free tier | ||
| Data-center locations | ||
| Regions | — | Not applicable — self-hosted; managed mailcow runs in Germany |
| Tags | ||
| Tags | free tierapi access | free tieropen sourceself hostable |
| Visit Postmark → | Visit Mailcow → | |
Postmark
Pros
- + Transactional/broadcast stream separation protects application email reputation
- + Real free tier: 100 emails/month forever, no expiry — good for evaluating deliverability honestly
- + Published, tiered pricing with explicit overage rates and no sales-gated numbers
- + Deep per-message delivery and bounce analytics with sandbox testing mode
- + Boring in the good way: stable SMTP/API since 2010 with the team carried through the 2022 acquisition
Cons
- - Per-email cost is well above SendGrid at volume
- - No marketing campaigns, contact lists, or automation — transactional and broadcast sending only
- - Inbound processing, long retention, and dedicated IPs gated behind higher tiers and volume minimums
- - Owned by ActiveCampaign since 2022; long-term product consolidation is a real, if mild, risk
Mailcow
Pros
- + Free GPLv3 suite with the full mail stack (groupware, ActiveSync, Rspamd, ClamAV) — no seats, no volume caps
- + Specific, credible hardware requirements and detailed ops documentation
- + Active monthly release train with prompt security patches (e.g. CVE-2026-33278 fix in May 2026, forced 2FA in March 2026)
- + Vendor-backed escape hatches: shared mailcow from EUR 8.90/mo and managed mailcow from EUR 54.90/mo in Germany
Cons
- - Needs real server management skills (Docker, DNS, PTR, firewall chains, updates)
- - 6 GiB RAM minimum rules out the cheapest VPS tiers
- - IP reputation and deliverability are entirely self-managed on the free tier
- - Community-only support with no SLA behind the open-source software
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