Set up your sending domain (or use ours) in an afternoon

The fastest way to start outbound is to not touch DNS at all: on a paid plan or the trial, send on a shared platform domain that is already authenticated, and you can have your first email out within minutes. If you want mail to come from your own domain (which most teams eventually do) the work is six DNS records SEMAOS shows you (an ownership TXT, three DKIM CNAMEs, plus SPF and MX on a mail. subdomain for the custom MAIL FROM), and a DMARC record you publish yourself. Add them, wait for DNS to propagate, and you can send the same afternoon, at the warmup cap of 100 a day to begin with. This post walks both paths so you can pick the one that fits your first week.

Should you use your own domain or a shared one?

It depends on how soon you need replies to come from your real address. A shared platform domain is the zero-setup option: nothing to configure, good enough to learn the product and send your first sequence. Your own domain takes an afternoon of DNS work but means recipients see your brand and can reply straight to you. Most teams start on the shared domain while DNS propagates, then switch.

What is a sending domain?

A sending domain is the domain in the From address that receiving servers (Gmail, Outlook, Yahoo) use to decide whether to trust your mail. They do not judge it by how it looks. They check DNS records published under that domain to confirm the message really came from a server you authorized, and they track that domain's complaint history over time. A brand-new domain with no records and no history looks exactly like a spammer to them.

A common choice is to send from a subdomain (say mail.yourcompany.com or go.yourcompany.com) rather than your root domain. That keeps outbound reputation separate from the domain your team uses for normal one-to-one email, so a rough patch on a campaign does not drag down your everyday mail.

Which DNS records do you actually need?

Three, plus one envelope setting. Each answers a different question the receiver asks.

The opening post in the deliverability series covers what each record does in detail. In short: SPF is a TXT record listing who can send for you, and DKIM signs every message so a receiver can verify it was not tampered with in transit. DMARC ties the two together and tells receivers what to do with mail that fails: start at p=none and read the aggregate reports for a couple of weeks, move to p=quarantine so failures go to spam rather than the inbox, then tighten to p=reject after about 30 days of clean reports. The custom MAIL FROM points the bounce-handling envelope at your own domain so everything aligns.

Do the new Gmail and Yahoo rules apply to you?

If you send roughly 5,000 messages or more per day to personal Gmail or Yahoo accounts, you are a "bulk sender" under rules both providers began enforcing in 2024 and have been ramping up through late 2025. Bulk senders must authenticate with SPF and DKIM, publish a DMARC record (at minimum p=none, though aligned DMARC is recommended and likely to become required), offer one-click unsubscribe on marketing mail, and keep their spam complaint rate below 0.3%. Google advises staying under 0.1% for reliable placement. Smaller senders are not formally bound by the 5,000-per-day threshold, but the same authentication is what keeps any mail out of spam, so set it up regardless. Transactional mail like password resets and order confirmations is exempt from the unsubscribe rule; promotional and outbound sales mail is not.

How long does propagation take?

DNS changes are not instant. Most records show up within fifteen minutes to a couple of hours, and occasionally a resolver takes the full 24. To see which resolvers have caught up, check the propagation from several of them. Practically, you can usually verify SPF, DKIM, and DMARC within the hour using a validator, then send a test message to a Gmail and an Outlook address and check the headers show pass on all three. The free deliverability scan checks your root domain's SPF and DMARC records and the DKIM keys your mailbox provider publishes, along with your MX records, sending setup and domain age. It doesn't look at the DKIM CNAMEs or the mail. subdomain records above. SEMAOS's own verify step checks the DKIM ones. Do not start real volume until that test passes.

What about warming up a brand-new domain?

A domain with no sending history has no reputation, and dumping thousands of messages on day one is the fastest way to get filtered. Warmup means ramping volume gradually: start well below what you eventually plan to send, to the contacts most likely to engage, and raise it week by week for about a month. How to warm a new sending domain in 30 days has the schedule. We come back to reading your bounce rate at the end of this series, and the bounce-rate deep dive in the deliverability series covers digging out of a throttle; for now, just know that a new domain needs a runway, which is another reason the shared domain is a sensible place to start.

How does SEMAOS handle this?

You can send on the SEMAOS shared platform domain (send.semaos.io) with no DNS setup at all: SPF, DKIM, DMARC, and MAIL FROM are already in place. When you are ready to bring your own domain, SEMAOS shows you the ownership, DKIM, SPF and MX records, checks the ownership and DKIM records, and the domain is not usable for sending until both verify; DMARC is yours to publish, and the verify step doesn't check it. New custom domains are automatically capped on a 21-day warmup ramp (100 / 500 / 2,000 sends per day) or by volume sent so far, whichever is stricter, before your plan limits apply, so a fresh domain builds reputation instead of burning it. Both paths are platform sending, which starts on the Solo plan or the 30-day trial; the Free plan sends from your own Gmail or Outlook mailbox instead. Pick the shared domain to start outbound today; switch to your own once DNS has propagated.

Next in this series: importing and cleaning your first contact list.