Which should I start with?

Postal, unless you can already name the specific limitation that makes PowerMTA necessary. Postal is free, so trying it costs you a server and an afternoon. PowerMTA costs thousands a year and gives you controls that only matter at volumes most senders never reach.

Is there a free version of PowerMTA?

No. It is commercial software owned by Bird — formerly Port25, then SparkPost — with no free or open-source edition, and a licence is mandatory to run it legally. If you have been offered a cheap copy, it is not a legitimate licence.

What does PowerMTA actually do that Postal does not?

Fine-grained delivery control per receiving domain — rate, concurrency and retry behaviour tuned separately for each — plus granular IP pool management for rotation and warm-up, and detailed per-message accounting. At high volume these decide whether mail is accepted or deferred. Below that volume they are controls with nothing to control.

Can Postal handle serious volume?

It handles a great deal more than most people running it will ever send. The honest limit is not a message count but a control problem: when you need different delivery behaviour for different receiving domains and several IPs rotating on a schedule, you will feel Postal's simplicity as a constraint.

Do I need campaign software as well?

With either of them, yes, if you want subscriber lists and newsletters. Both are delivery engines with no campaign tooling. MailWizz is the usual pairing at the PowerMTA end; Mautic or listmonk work with Postal.

Can I migrate from Postal to PowerMTA later?

Yes, and that is the sensible path. Your campaign software, DNS records and IP reputation carry over — it is the delivery layer underneath that changes. Starting on Postal costs you nothing and teaches you whether you actually need the commercial one.

Do you sell PowerMTA licences?

No. We sell the server. The licence comes from Bird, and we earn nothing whichever you choose — which is why this page is comfortable telling most readers to use the free one.

Is Port 25 guaranteed on every plan, or just open?

Both, depending on the range, and the difference is worth knowing before you buy. Outbound Port 25 is open by default on all 16 plans — no ticket, no approval step. On NVMe VPS, Cloud VPS, Classic VPS and VDS it is written into the published plan specification. On it is open because of how the network is run rather than as a documented guarantee. In practice it behaves the same on all of them, but if your business stops when you cannot send, buy the range that puts it in writing.

Postal vs PowerMTA

One is free. Start there.

Postal is MIT licensed and costs nothing. PowerMTA is commercial software from Bird with no free edition and licences reported around $8,000 a year. Both deliver mail directly. The question is not which is better — it is whether you have hit a wall that only the commercial one gets you past.

Postal: MIT, free
PowerMTA: licence mandatory
Both deliver mail
PowerMTA: per-domain control

Side by Side When PowerMTA Is Worth It

Cost of trying Postal first

MIT licence · you only pay for the server

Postal: direct delivery, API, tracking
Postal handles inbound mail too
PowerMTA has no free edition
Neither includes campaign tools

The Short Answer

Start with Postal. It is free, MIT licensed, delivers mail directly from your own IP and gives you queues, tracking and an HTTP API. PowerMTA is a serious piece of software and it is commercial only — owned by Bird, no open-source edition, licence mandatory, with published third-party estimates around $8,000 a year. It earns that at the point where you need delivery tuned separately for each receiving domain and several IP addresses rotating on a warm-up schedule. That point is real, and most senders never reach it. Since trying Postal costs nothing but a server, there is no good reason to buy first and find out afterwards.

Postal: MIT, free, 2 cores / 4 GB / 25 GB minimum, MariaDB 10.6+.
PowerMTA: commercial from Bird, quote-priced, no free edition.
Both deliver mail themselves; neither manages subscribers or campaigns.
Postal also receives mail; PowerMTA is an outbound delivery engine.
The dividing line is per-domain throttling and IP pool management at volume.
Migration later is normal — the layers above and below stay put.

Side by Side

Postal's licence and minimum specification were read in the project's own repository and documentation on 17 August 2026. PowerMTA's ownership and commercial-only status are from published sources; the cost figure is a third-party estimate, not a vendor quote.

	Postal	PowerMTA
Licence	MIT — open source	Commercial, owned by Bird
Cost	Free	Quote only; third-party estimates around $8,000/yr
Free edition	The whole thing is free	None exists
Delivers mail itself	Yes	Yes
Inbound mail	Yes — handles both directions	Outbound delivery engine
Web interface	Built in	Configuration and accounting files
HTTP API	Yes	Integrations vary by deployment
Per-domain throttling	Basic controls	Granular — the main reason to pay
IP pool management	Workable at small scale	Granular rotation and warm-up
Documented minimum	2 cores, 4 GB RAM, 25 GB disk	Dedicated resources in practice
Database	MariaDB 10.6+ (not MySQL)	n/a
Campaign tools	None — pair with campaign software	None — pair with campaign software
Suggested plan	Business NVMe VPS — $12.95	Business VDS (Xeon E5) — $32.95

When PowerMTA Genuinely Earns Its Licence

Four situations where it is the right answer, and the test that tells you whether you are in one of them.

Different receiving domains need different treatment You already know which providers defer you, at what rate they accept, and how long to back off. Being able to set that per destination is what you are buying. Justified
You are managing a pool of IPs, not an IP Rotation, scheduled warm-up of new addresses, and isolating transactional from marketing traffic. With one address there is nothing here to use. Justified
Per-message accounting is a requirement, not a nicety Sometimes contractual or regulatory. If somebody audits your delivery records, detailed accounting files stop being optional. Justified
The licence is small next to the value of mail landing At genuine scale, a few thousand a year against revenue that depends on inbox placement is not a difficult decision. Justified
The test: can you name the wall you hit? If you cannot describe the specific limitation in one sentence, you have not hit it. Run Postal, send real mail, and see what breaks. That answer costs nothing to obtain and is worth more than any comparison page, including this one. Start here

Postal and PowerMTA Questions

Port 25 open, dedicated IPv4, rDNS on request — whichever you run.

From $4.95 a month, with additional IPv4 addresses available if you get to the point of managing a pool — plus a 7-day money-back guarantee.

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