mailcow

mailcow is an open-source Docker-based groupware and email suite built from established components including Postfix, Dovecot, Rspamd, SOGo, Redis, MariaDB, Nginx, and Unbound. Its main advantage is a modern admin UI around a full mail-server stack.

Judged purely as an API. What the request contract guarantees on retry, how complete the webhook event coverage is, whether suppressions are readable and writable programmatically, and how much the message log retains when something needs debugging in production.

Against high-frequency programmatic sends where a missed delivery is a product failure, mailcow covers event stream and the suppressions API, and does not cover idempotency keys, webhook coverage, batch sending, and SDK breadth. Whether that gap matters depends on how central those are to the build.

• Idempotency keys: No
• Webhooks: No
• Event stream: Yes
• Operating since: Not published
• Suppressions API: Yes
• Best published rate per 1,000: Tiers not published in comparable form
• Batch sending: No
• SDKs: None
• Deliverability: Self-hosted deliverability depends on DNS, IP history, spam controls, and operator discipline. mailcow bundles Rspamd, DKIM support, quarantine controls, and administration UI around the stack.

Self-hosted deliverability depends on DNS, IP history, spam controls, and operator discipline. mailcow bundles Rspamd, DKIM support, quarantine controls, and administration UI around the stack.

Teams that want to self-host a full email and groupware suite.

Small product teams trying to avoid mail-server operations.