Postal Email Server

Set up a self-hosted mail server (Postal) for an AI job-application assistant that sends applications on users' behalf. A normal email provider wasn't a good fit here, since replies needed to come back into the app automatically for many different users.

What I did:

• Installed and configured Postal on a Linux server using Docker
• Set up SPF, DKIM, MX, and return-path DNS records for authenticated, reliable delivery
• Tested real email sending and receiving end-to-end, confirming SPF and DKIM pass
• Built a small Python tool that gradually ramps up sending volume on a new domain to protect its reputation
• Scheduled it to run daily with cron
• Put the server behind Nginx as a reverse proxy, with TLS certificates from Let's Encrypt

Why it matters: Email providers judge new domains by their history, so a sudden jump in volume can hurt deliverability. This setup lets a new domain build its reputation gradually.