Instead of SendGrid and Mailgun

Transactional email delivery for applications.

Keep paying

Deliverability is the product. You can run Postal, and you can get your mail delivered, but the first month goes on SPF, DKIM, DMARC and IP reputation.

You lose: An IP that has been sending reputation-building mail for a decade.

Start here

Postal

MITa weekendactive

A real mail server for applications, with bounce handling and a web UI. You still own the reputation.

github.com/postalserver/postal postalserver.io

A database, object storage or mail config, plus backups.

Also worth a look

StalwartAGPL-3.0a weekendactive
Modern and well-built, with JMAP and a clean admin model. Also yours to warm up.
github.com/stalwartlabs/stalwart stalw.art
MaddyGPL-3.0a weekendactive
One binary, all-in-one SMTP and IMAP. Small and deliberate; you bring the DNS records.
github.com/foxcpp/maddy maddy.email

What the desk has written

Facts checked 8 November 2026. Licences, activity and archive status come from each project's own repository; the verdict and the cost lines are the desk's.