Overview

Postal is a fully featured open-source mail delivery platform for sending and receiving email, written in Ruby. It is built for developers and operations teams who want reliable outgoing email from their own applications — with a REST API, webhooks and per-credential statistics rather than a traditional mail client.

Key Features

• REST API & Webhooks: send mail programmatically and receive delivery events
• Transactional & Bulk Mail: handles application and marketing mail from one platform
• Incoming Email: receive and process inbound mail via webhooks
• Per-Credential Stats: separate SMTP/API credentials with usage tracking per sender
• Authentication: automatic SPF, DKIM and DMARC configuration
• Archive & Search: message archive with full-text search and delivery logs

Why Use It

Postal gives you ownership of your outgoing mail infrastructure. Instead of relying on a third-party sender, you run your own delivery platform with the tools developers expect — an API, webhooks and observability — while keeping reputation under your control.

Use Cases

• Sending transactional email (password resets, notifications) from your own servers
• Bulk and broadcast mail for products and services
• Receiving and processing incoming email in an app

Platforms

Linux (commonly deployed via Docker), with a web-based admin interface.

Licence

Open Source — MIT.

Website

https://postalserver.io/

Alternatives

• Mailcow — dockerised all-in-one mail server suite