Self-Hosting Email vs a Managed Provider: An Honest Cost Look

Every few months someone on a founder forum asks why they're paying for email when a small VPS and an afternoon with Postfix would do the job. The honest answer is that it can do the job, and that the afternoon is the cheapest part.

This is a comparison of running your own mail server against paying a managed provider, written by a company that runs its own mail infrastructure and sells a managed product. We'll try to be fair to both sides, including the cases where self-hosting is the right call.

What "self-hosting email" actually involves#

A working mail setup for a company isn't one program. At the time of writing, a typical open-source stack looks something like this:

• An MTA such as Postfix or Exim, to send and receive over SMTP.
• An IMAP server such as Dovecot, so people can read their mail.
• Spam and virus filtering, commonly Rspamd or SpamAssassin plus ClamAV.
• DKIM signing, often handled by the spam filter or OpenDKIM.
• A webmail client if anyone wants to read mail in a browser.
• TLS certificates, renewed automatically.
• Monitoring, logs and backups for all of the above.

All-in-one projects such as Mailcow and Mail-in-a-Box bundle these pieces with a setup script and an admin panel, which removes much of the initial assembly. They don't remove the ongoing work.

The parts that cost more than the server#

Reputation#

Receiving mail is the easy half. Sending mail that lands in inboxes is where self-hosters spend most of their time. Big mailbox providers judge mail partly by the sending IP's history. A fresh VPS IP might have been used by a spammer last year, might sit in a range that blocklists treat as dynamic or residential, or might simply have no history at all, which isn't much better.

You'll need a PTR (reverse DNS) record that matches your hostname, correct SPF, DKIM and DMARC, and patience. Several large cloud providers restrict outbound port 25 on new accounts by default, so check before you build anything.

Maintenance#

Mail servers are long-lived, internet-facing services that parse untrusted input all day. That means security updates for the OS, the MTA, the IMAP server, the filter and the webmail, and occasional breaking changes when you upgrade.

Spam filtering quality#

Out of the box, an open-source filter is decent. Getting it to the level people are used to from a large hosted provider takes tuning, training and ongoing attention. Users notice both directions of failure: spam in the inbox and real mail in junk.

Being on call#

When mail stops, someone has to notice and fix it. With a managed provider that someone is their operations team. With self-hosting it's you, possibly on a weekend, possibly while traveling.

A rough way to compare costs#

Server costs are easy to compare and usually small. Time is the real variable. Instead of pretending to know your numbers, here's a worksheet:

Fill in your own hourly rate and be honest about how many hours a month you'd really spend. For a technical founder whose time would otherwise go into the product, even a few hours a month usually outweighs a subscription. For someone who already runs servers and enjoys it, the math can come out differently.