Postal

Postal is a self-hosted alternative to services like Sendgrid, Mailgun, or Postmark. It gives you a full mail delivery platform you run on your own servers, handling both incoming and outgoing email without depending on a third-party provider.

It's built for websites and web servers that need reliable, controllable email infrastructure. If you've outgrown transactional email SaaS pricing, want data sovereignty, or need to manage multiple mail servers under one roof, Postal fits that gap.

Key capabilities include:

• Web interface for managing mail servers, viewing logs, and monitoring delivery status without touching a command line
• Webhooks that notify HTTP endpoints when messages are delivered, bounced, or flagged, so your apps can react in real time
• IP pools for sending from different IP addresses, which helps build and protect sender reputation across different clients or use cases
• Spam and anti-virus filtering through integrations with SpamAssassin, rspamd, and ClamAV for both inbound and outbound message scanning
• Development mode that holds messages in the queue automatically, so you can test email flows without accidentally sending to real recipients
• Horizontal scaling so you can add capacity as send volume grows

Postal sits in the same category as other self-hosted mail servers, but it leans toward teams who want a polished management interface alongside the infrastructure control. Tools like Listmonk handle bulk campaigns; Postal focuses on transactional delivery infrastructure with multi-server management built in.