Postal is an open-source email infrastructure and self-hosted delivery platform. It functions as an SMTP mail server and inbound email gateway, providing the tools necessary to send and receive email through a privately managed infrastructure.
The system manages SMTP infrastructure for outgoing message delivery and provides capabilities for custom email receiving. It allows for the routing of incoming external emails to internal applications or websites for automated processing.
The platform includes support for multi-tenant domain mapping, event-driven webhook notifications, and plugin-based message filtering. It also incorporates queue-based delivery retries and DNS-based recipient validation to manage mail flow and server reputations.
