Overview
Mailcow: dockerized is a mail stack based on Postfix, Dovecot, and SOGo, integrating multiple Open Source components via Docker Compose. Poste.io is a proprietary solution (with a free version) delivered as a single Docker container, focused on administrative simplicity.
| Parameter | Mailcow | Poste.io |
|---|---|---|
| Architecture | Multi-container (15+) | Single container |
| License | GPLv3 | Proprietary (Free version available) |
| Min RAM | 4 GB (6 GB recommended) | 1 GB (2 GB recommended) |
| Webmail | SOGo | Roundcube |
| Database | MariaDB / Redis | SQLite (Free) / PostgreSQL (Pro) |
Performance
Mailcow is resource-intensive due to ClamAV, Solr (for full-text search), and Rspamd. It requires at least 4 GB of RAM to start. Mail indexing speed is high thanks to Solr, but CPU consumption is consistently above average. Poste.io consumes 3-4 times fewer resources. It runs on a VPS with 1 GB of RAM and is suitable for mail processing on low-end nodes. Poste.io uses custom C++/Go implementations for some protocols, reducing overhead from context switching between processes.
Configuration & complexity
Mailcow deployment is done via the generate_config.sh script and editing mailcow.conf. Management is handled through a sophisticated web panel where domains, mailboxes, and Rspamd policies are configured. Poste.io is configured with a single docker run command. The main configuration is exposed via environment variables. The Poste.io web interface is more minimalist and includes built-in real-time queue and log monitoring, simplifying debugging without SSH access.
When to choose what
Mailcow is suitable for corporate use requiring calendars, contacts (CalDAV/CardDAV), and a full Groupware environment. It is the choice for those who value full code control and no licensing restrictions. Poste.io is optimal for small projects, microservices needing to send notifications, or personal mail servers on cheap VPS. It is also the best choice if you need to deploy mail in 2 minutes without deep documentation study.
Cost / licensing
Mailcow is completely free. Paid services only include technical support from the developers. Poste.io follows a Freemium model. The free version lacks antivirus scanning, certain security tools, and multi-admin support. The Pro license starts at $449 (one-time or annually depending on the plan) and includes advanced filtering and PostgreSQL support.
Ecosystem & integrations
Mailcow offers a powerful API for automating mailbox creation and integration with external control panels. It includes a Netfilter container for automatically banning attackers (Fail2Ban analog). Poste.io focuses on self-sufficiency: Let's Encrypt, anti-spam, and a metric collection system are pre-configured inside the container. However, customizing individual components (e.g., replacing the anti-spam engine) in Poste.io is difficult due to its monolithic structure.
Verdict
Choose Mailcow if you have the resources (min 2 vCPU, 4GB RAM) and need a full open-source replacement for Exchange/Google Workspace. Choose Poste.io if resource efficiency is critical, deployment speed matters, and basic Roundcube functionality is sufficient.