Postal Mail Server Setup

What Postal is

Postal is an open-source platform for sending and receiving email, designed to be run by the organisation using it. It sits somewhere between a bare SMTP server and a hosted sending service: you get organisations and mail servers for separating traffic, an HTTP API and SMTP for sending, webhooks for delivery events, message history with searchable logs, and IP pools for controlling which addresses carry which mail.

It runs as a set of containers on your own server, so the data, the IPs and the configuration are yours.

When Postal is a good fit

• Developers want an API and webhooks like a hosted service, but the business wants to own the infrastructure.
• Several products or clients need separate sending environments with their own credentials and statistics.
• Support staff need to look up whether a particular message was delivered without reading raw logs.
• You want inbound routing to your application, for replies or parsing, alongside outbound sending.

If you only need a small outbound relay, plain SMTP server setup is simpler. If you need company mailboxes, Postal isn’t designed for that; a full mail server installation is.

What we set up

• Server sizing, provisioning and hardening for Postal and its database.
• Postal installation with HTTPS on the web interface and tracking domains.
• Organisations and mail servers structured around your brands, products or environments.
• Sending domains verified with SPF, DKIM and a return-path domain, plus DMARC.
• IP pools and reverse DNS for each sending address.
• Credentials for SMTP and API access, scoped per application.
• Webhooks for deliveries, bounces and link clicks posted to your systems.
• Message retention periods, size limits and tracking settings suited to your needs.
• Backups, updates and a documented upgrade procedure.

How we deliver it

1. Map your sending: which applications, which domains, which mail types, and at what volume.
2. Provision a server with open port 25 and PTR control, then install Postal.
3. Create the organisation and mail-server structure, then verify each domain.
4. Configure IP pools, placing transactional mail on its own pool where appropriate.
5. Connect one application first, verify webhooks and message logs, then connect the rest.
6. Warm up new IPs and monitor acceptance and deferrals.
7. Document the layout, credentials handling and upgrade steps.

Standards, monitoring and compliance

Postal handles DKIM signing and return-path domains, but DMARC, PTR records and TLS still need correct DNS and server configuration around it. We register your IPs with Microsoft SNDS and your domains with Google Postmaster Tools so you can watch reputation, and we feed bounces into suppression so they aren’t retried endlessly.

Running Postal day to day

Once Postal is live, most day-to-day work happens in its web interface. Support staff can search for a recipient and see whether a message was delivered, deferred or bounced, along with the receiving server’s response. Developers can review webhook deliveries and retry failures. Administrators can see per-server statistics and spot when one application’s traffic changes.

Behind the interface, the server still needs care: operating system updates, Postal upgrades, database backups, disk space for retained messages and certificate renewal. We document each of these routines so they can be handled by your team or by our monitoring and maintenance service.

What affects timeline and cost

• Number of organisations, mail servers and domains.
• How many IPs and pools, and how much warm-up they need.
• Integration work for applications and webhook consumers.
• Retention requirements, which drive storage size.
• Whether inbound routing is needed.

Common Postal mistakes

Underestimating storage when message retention is left long. Putting every application on one mail server so statistics and credentials are mixed. Skipping the return-path domain so SPF doesn’t align. Upgrading without reading the release notes. We plan for each of these at the start.

See all email infrastructure services, read our email infrastructure guide, or get in touch.

Frequently asked questions