Is this page just an advert for your hosting?

Partly, and it says so. The checklist is written to be useful whoever you buy from — the requirements are the software vendor's, not ours. Three lines in the table answer No for us, including backups and managed setup, because a checklist that scored us full marks would be worthless to you.

What single thing disqualifies a host fastest?

Blocked outbound Port 25 with no route to having it opened. Most large cloud providers block it by default: AWS requires a written request that can be refused, and Google Cloud blocks connections to external port 25 with no unblock path at all. If you intend to deliver mail yourself, that ends the conversation.

Do you hold a backup of my subscriber list?

No, on any plan, at any price. We hold no copy of your data at all. A subscriber database is exactly the thing you cannot afford to lose, so set up your own off-site backup before your first import.

Will you install and configure it for me?

No. Every plan is unmanaged. Support answers platform and network questions and sets your reverse DNS, but does not install your stack, tune your database or debug your sending. If you want that, you want a managed provider, and we would rather say so than take the order.

How do I know a provider will not change its mind about Port 25?

You do not, entirely — read the acceptable use policy rather than the sales page, since that is the document that governs. Ours allows opt-in marketing and transactional mail and says plainly that repeated blacklisting or high complaint rates can get sending disabled on the affected server.

Which plan should I actually pick?

Start from the software's published requirements rather than from a price. The suggested plan on this page is derived from them, and the product page for this software explains the reasoning in more detail.

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 · Choosing a Host

Postal publishes a real minimum. Most cheap plans miss it.

Unusually for this category, Postal states its requirements plainly: 2 CPU cores, 4 GB RAM, 25 GB of disk, Docker, and MariaDB 10.6 or newer — with MySQL explicitly not accepted in its place. That turns host selection into arithmetic, which is a pleasant change.

Vendor requirements
Port 25 open
Dedicated IPv4
Custom rDNS

The Checklist Questions to Ask

Documented minimum RAM

4 GB

2 cores · 25 GB disk · MariaDB 10.6+

Port 25 open both directions
Docker runs fine on every plan
Entry plans are below the minimum
MySQL will not substitute for MariaDB

The Short Version

Postal is the only free, open-source package here that delivers mail itself, and it is also the only one with a hard published minimum. Two CPU cores, 4 GB of RAM and 25 GB of disk, running as a Docker Compose stack, with MariaDB 10.6 or higher — the project states that MySQL is not supported in its place. Add the network requirements every self-delivering sender has, and the shortlist of suitable hosts gets short quickly: entry-level plans at any provider will not do.

Documented minimum: 2 CPU cores, 4 GB RAM, 25 GB disk.
Database: MariaDB 10.6+. MySQL is explicitly not a substitute.
Runtime: Docker and Docker Compose, plus git, curl and jq.
Network: outbound and inbound Port 25 — Postal handles both directions.
Licence: MIT. Free, which is why it is the sane alternative to a commercial MTA.
Not campaign software — no lists, no newsletters, no automation.

What to Demand From Any Host

The requirements come from the software vendor; the verdicts are ours and are answered straight. Where the answer is no, it is no.

Requirement	Why it matters	Us
At least 2 CPU cores and 4 GB RAM	This is Postal’s published minimum, not a recommendation. Below it you are fighting the software rather than using it.	Yes From the Business tier upward — the cheapest plans do not qualify
At least 25 GB of disk	The queue, the message store and MariaDB all live here, and message retention grows it steadily.	Yes Met from the Business tier up
Docker and Docker Compose	This is the supported install path. A host that restricts containers or runs a kernel that fights Docker is not suitable.	Yes KVM with your own kernel — Docker runs normally
MariaDB 10.6 or newer	The project states MySQL is not supported in its place. If you are migrating from a MySQL estate, plan for this.	Yes Root access — install whichever you need
Outbound Port 25	Postal delivers mail directly. Without Port 25 the entire reason to run it disappears.	Yes Open by default, no ticket
Inbound Port 25 unfiltered	Postal handles incoming mail too. Providers that filter inbound SMTP break half of what it does.	Yes Nothing filtered at our end
A dedicated IPv4 and custom rDNS	You are now the mail server, so the PTR record and the IP reputation are yours to get right.	Yes Both included; rDNS set free on request
IPv6	Not required, but some setups expect it. Worth confirming for your chosen location.	Depends Varies by datacenter
Someone to watch deliverability	Running an MTA means owning bounces, complaint loops and blocklist entries. Nobody will tell you your reputation is sliding.	No Unmanaged — monitoring is yours

Sources, checked 17 August 2026

Read at each vendor's own documentation rather than taken from a summary. Follow the links and check for yourself — figures like these move.

MIT licence, and “a complete and fully featured mail server” github.com/postalserver/postal

The 2 core / 4 GB / 25 GB minimum, and MariaDB 10.6+ with MySQL not supported in its place docs.postalserver.io

Four Questions Worth Asking Before You Pay

Ask any provider, including us. The answers are more revealing than a feature list, and a vague reply is itself an answer.

“Does this plan actually meet 2 cores and 4 GB?” Compare against the plan page rather than the marketing copy. Below the minimum, Postal will disappoint you. Ask
“Is inbound SMTP filtered?” Plenty of providers open outbound Port 25 and quietly filter inbound, which breaks Postal’s receiving side. Ask
“Can I run Docker without restrictions?” Container-hostile virtualisation makes the supported install path painful. Ask
“How quickly can I get a PTR record set?” You are the mail server now. A slow rDNS process delays your first send. Ask

We would rather answer these before you order than refund you afterwards. Ask us directly →

Which Plan Fits

Derived from the requirements above rather than from a price target. If your list or sending volume is unusual, ask us rather than guessing from this.

Business NVMe VPS

Matches the documented minimum almost exactly — 2 cores and 4 GB — with NVMe for MariaDB and the queue.

NVMe VPS

2 Cores · 2 GB RAM
30 GB NVMe · 10 Gbps Port

$12.95/mo

Compare NVMe VPS

This is a starting point, not a rule — list size and sending frequency matter more than the software itself. See all plans · compare all six packages · ask before you order.

Choosing a Postal Host

Port 25 open, dedicated IPv4, rDNS on request.

From $4.95 a month with root access from the first second, and a 7-day money-back guarantee if the fit turns out to be wrong.

See All 16 Plans Ask Before You Order