maddy

maddy is a self-hosted mail server that implements SMTP for outbound and MX receipt, IMAP storage, DKIM, SPF, DMARC, DANE, and MTA-STS. It replaces the classic Postfix plus Dovecot plus OpenDKIM style stack with one daemon and one configuration model.

An agent stack treats email as a two-way primitive. Inbound has to arrive as structured JSON a tool call can consume, sends have to be safe to retry when a model loop repeats itself, and every action needs an audit trail. A provider without inbound parsing only solves half the problem.

Against inbound parsing into tool calls and model-generated sends that must not duplicate, maddy covers inbound parsing and multi-tenant support, and does not cover idempotency keys, webhook coverage, event stream, batch sending, and SDK breadth. Whether that gap matters depends on how central those are to the build.

• Inbound parsing: Yes
• Idempotency keys: No
• Webhooks: No
• Operating since: Not published
• Event stream: No
• Best published rate per 1,000: Tiers not published in comparable form
• Batch sending: No
• SDKs: None
• Multi-tenant: Yes

Self-hosted deliverability depends on DNS, IP reputation, queue management, bounce handling, and ongoing abuse controls. maddy includes DKIM, SPF, DMARC, DANE, and MTA-STS building blocks.

Infrastructure teams that want a compact self-hosted mail server with modern authentication primitives.

Product teams that need managed deliverability and support.