Postal

Postal is a self-hosted mail server designed as an open-source alternative to SendGrid or Mailgun. Handles outbound and inbound, RESTful API, multi-domain. Operationally heavier than just running Postfix.

The question here is which one a backend engineer would rather operate. That means SDK depth in the language already in use, whether a retry can safely be replayed, how much the event log tells you when a customer says the email never arrived, and whether the pricing curve stays sane as volume grows.

Against password resets, receipts, and magic links shipped from application code, Postal covers developer experience, SDK breadth, event stream, and webhook coverage, and does not cover idempotency keys. Whether that gap matters depends on how central those are to the build.

• DX score: 6/10
• SDKs: node, ruby, php
• Idempotency keys: No
• Operating since: Not published
• Event stream: Yes
• Best published rate per 1,000: Tiers not published in comparable form
• Webhooks: Yes
• Deliverability: You own it. Reputation depends on your IP, warmup discipline, and authentication.
• Free tier: Free, self-hosted

You own it. Reputation depends on your IP, warmup discipline, and authentication.

Teams with infra ops capacity that want full control of their mail delivery.