postalserver/postal

Analysis updated 2026-06-24

★ 16,511RubyAudience · ops devopsComplexity · 4/5Setup · hard

Mindmap

mindmap
  root((postal))
    Inputs
      Outgoing SMTP from your app
      Incoming mail via MX
      API calls
    Outputs
      Delivered email
      Webhooks
      Bounce and click tracking
    Use Cases
      Self-host transactional email
      Replace Sendgrid or Mailgun
      Process incoming mail for an app
    Tech Stack
      Ruby
      SMTP
      MariaDB

mindmap root((postal)) Inputs Outgoing SMTP from your app Incoming mail via MX API calls Outputs Delivered email Webhooks Bounce and click tracking Use Cases Self-host transactional email Replace Sendgrid or Mailgun Process incoming mail for an app Tech Stack Ruby SMTP MariaDB

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What do people build with it?

USE CASE 1

Self-host transactional email for password resets and receipts

USE CASE 2

Replace a paid Sendgrid or Mailgun account on your own server

USE CASE 3

Receive incoming mail and forward it to a webhook in your app

What is it built with?

RubySMTPMariaDBDocker

How does it compare?

	postalserver/postal	docusealco/docuseal	spree/spree
Stars	16,511	16,503	15,421
Language	Ruby	Ruby	Ruby
Setup difficulty	hard	easy	moderate
Complexity	4/5	3/5	4/5
Audience	ops devops	developer	developer

Figures from each repo's GitHub metadata at analysis time.

How do you get it running?

Difficulty · hard Time to first run · 1day+

Needs a VPS with proper DNS, MX, SPF, DKIM records and a non-blocked port 25 to actually deliver mail.

In plain English

Postal is a full-featured open-source mail delivery platform for sending and receiving email, designed to be self-hosted on your own servers. The README describes it as comparable to commercial email delivery services like Sendgrid, Mailgun, or Postmark, but free to run yourself. Those services handle the infrastructure for sending transactional emails (like password resets, order confirmations, and notifications) on behalf of websites and web applications. By running Postal yourself, you own the email infrastructure rather than paying a third-party service and being subject to their pricing and data policies. It handles both outgoing mail (SMTP, the standard protocol for sending email) and incoming mail. The project is written in Ruby and is available with installation documentation and a full feature list on its documentation site. The README itself is sparse and points to external documentation for setup details.

Copy-paste prompts

Prompt 1

Walk me through installing Postal on a Ubuntu VPS with Docker for outgoing transactional email

Prompt 2

Help me point my domain MX and SPF records at a fresh Postal install

Prompt 3

Show me how to send mail from a Node app through Postal over SMTP with a working code sample

Prompt 4

Configure Postal to forward incoming mail to a webhook in my web app

Frequently asked questions

What is postal?

Self-hosted mail delivery platform for sending and receiving transactional email. Open-source alternative to Sendgrid, Mailgun, or Postmark that you run on your own servers.

What language is postal written in?

Mainly Ruby. The stack also includes Ruby, SMTP, MariaDB.

How hard is postal to set up?

Setup difficulty is rated hard, with roughly 1day+ to a first successful run.

Who is postal for?

Mainly ops devops.

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