SuperMailOS
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Deliverability

Your reputation is our job. Not your weekend.

We run the mail server and the sending IPs, so the technical work that decides whether your mail reaches the inbox is ours to carry. You get the result without operating any of it.

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Included on every plan. See all features

Re: Signed — kickoff Thursday?Sent · just now
  1. Your messageyou@acme.co → maya@northwind.com
  2. SPFSent from a server acme.co allows
  3. DKIMSigned on the way out · d=acme.co
  4. DMARCAligned with acme.co
  5. InboxDelivered to Maya's inbox

SPF, DKIM and DMARC all pass because we publish and sign them for you — and we block sending from any domain until its records verify.

01 What you get

What we operate for you.

Because we run the mail server, the parts other tools leave as DIY are simply handled.

DKIM on every message

Each outgoing message is cryptographically signed with a key whose public half we publish in your DNS. No per-message setup, no forgetting to sign.

SPF & DMARC from the real zone

Your SPF and DMARC records are generated from the mail server's own zone — not a copied template — and verified live before sending is ever allowed.

DMARC reports, parsed

Aggregate DMARC reports are collected and turned into a dashboard, so you can see every source sending as your domain instead of reading raw XML. On every plan.

New-domain warm-up

A brand-new sending identity has no reputation, so volume ramps automatically as your domain builds a track record — rather than spiking on day one and looking like a spammer.

IP reputation & reverse DNS

The outbound sending IPs are watched for blocklist status and correct PTR records, day and night, so a reputation problem is caught before your mail feels it.

Enforced TLS (MTA-STS)

Inbound mail is required to use TLS via MTA-STS, with TLS-RPT failure reporting, closing off the downgrade attacks that quietly strip encryption in transit.

02 Your side

The honest part: your side of the deal.

Deliverability is a shared responsibility. We carry the infrastructure; a few habits keep the reputation we manage healthy.

01

Send mail people asked for.

SuperMailOS is person-to-person business email, not a bulk blaster. Unsolicited bulk sending is the fastest way to wreck placement for everyone, so it isn't the product for that.

02

Keep your lists clean.

Repeated bounces and spam complaints are the loudest negative signals a receiver sees. Remove addresses that bounce and honour unsubscribes immediately.

03

Be consistent.

A stable from-address that people recognise and reply to builds the engagement history receivers reward.

03 Questions

Deliverability questions, answered.

Something else? Write to us — a real person answers, usually the same day.

Talk to us
Do I have to configure SPF, DKIM and DMARC myself?+
No. SuperMailOS generates them from the mail server's own zone, publishes them (one click on supported DNS hosts, copy-paste elsewhere), verifies them live before you can send, and signs DKIM on every message. Aggregate DMARC reports are parsed into a dashboard for you.
What is new-domain warm-up and do I need to run it?+
A new sending domain has no reputation, so a sudden burst of mail looks suspicious to receivers. Warm-up ramps volume gradually as your domain establishes a track record. On SuperMailOS it runs automatically from your first message — there is nothing for you to schedule.
Why must my domain be verified before I can send?+
Sending from a half-configured domain fails authentication and teaches receivers to distrust you. SuperMailOS blocks sending until your records verify, which protects both your reputation and the shared sending infrastructure everyone relies on.
Can you guarantee my mail lands in the inbox?+
No honest provider can guarantee placement — receivers make the final call using signals like engagement and complaint rates. What we do is remove the technical causes of spam foldering and monitor the reputation signals continuously, so you start from the strongest possible position.

Bring your domain. We'll carry the reputation.

Add a domain, verify the records we generate, and send from a foundation that's monitored around the clock. The first 14 days are free.

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