Cold Email Domain Setup: What to Buy and How to Wire It

Cold email domain setup is the one part of outbound where the decisions are cheap to make correctly and expensive to fix later. A burned domain does not recover on a useful timescale. You retire it and start over. So this is the build order, with the arithmetic that sizes it.

This is for teams standing up outbound for the first time, or rebuilding after a domain went bad.

Size the Build From Your Target Volume

Work backwards from meetings. Say you need 12 meetings a month. At a 2% cold-email meeting rate that is 600 contacts a month reached, and at a three-step sequence that is roughly 1,800 sends a month, or about 90 a working day.

A healthy mailbox carries 30 to 50 cold sends a day. So 90 a day is two to three mailboxes, not one working hard. Keep two to three mailboxes per domain, and you need one or two sending domains plus a spare.

Run that math before you buy anything. Teams routinely buy one domain, create one mailbox, push 200 sends a day through it, and conclude that cold email does not work.

Never Send From Your Primary Domain

Reputation attaches to the domain. If your main domain sends both invoices and cold outreach, one bad list takes down billing, support and recruiting mail with it.

Buy lookalikes. For grobotlabs.com that is the kind of thing that reads as obviously the same company: a .co variant, a hyphenated variant, a get- or try- prefix. Avoid anything that looks like a typosquat of a different brand, and avoid the cheap new TLDs, some receivers treat certain TLDs as a negative signal on their own.

Every sending domain needs a real website. Not a parked page, a page that loads, carries your brand, and redirects or links to the main site. A domain that sends mail and serves nothing is a pattern filters recognize.

Let a new domain age before you send from it. Two to four weeks between registration and first send is the cheapest reputation you will ever buy, and you can spend that time on warmup anyway.

The DNS Records, Concretely

Four things go in DNS for each sending domain, and Google now enforces the first three for bulk senders rather than merely recommending them.

• SPF, one TXT record, one only. Two SPF records is a hard failure. Keep it under the 10-lookup limit; nested includes from several vendors is the usual way teams exceed it without noticing.
• DKIM, published by whoever hosts the mailbox. Google Workspace and Microsoft 365 both generate the key and hand you the record; the common mistake is enabling signing in the admin console but never publishing the DNS entry.
• DMARC, a TXT record at _dmarc.yourdomain. Start at p=none with a reporting address so you can see what is failing, then move to quarantine once alignment is clean. Google requires the record to exist; p=none satisfies that.
• PTR, reverse DNS on the sending IP. If you are on a shared provider this is theirs and already set. If you are sending from your own infrastructure, it is yours and it is frequently missing.

Also add MX even on domains that only send. A domain that cannot receive mail cannot receive replies or bounce notifications, and the absence of MX is itself a signal.

Mailboxes That Look Like People

Use real names. sarah@ beats sales@, info@ and hello@ by a wide margin, because role addresses are exactly what bulk senders use.

Set a display name, a photo, and a short plain-text signature: name, title, company, one link at most. No image signature, no logo, no social icon row. A cold email from a person does not have a marketing footer.

Two to three mailboxes per domain is the ceiling worth using. Six mailboxes on one domain concentrates risk on a single reputation.

Warmup Is Three to Four Weeks and Cannot Be Compressed

A new mailbox starts at a handful of sends a day and ramps gradually, with real conversational replies mixed in. Week one is single digits. By week four it can carry campaign volume.

The temptation is to skip it because the pipeline is empty now. Skipping warmup is the most reliable way to burn a domain in its first month, and then the pipeline is empty and you have no infrastructure.

Keep some warmup traffic running permanently at low volume. It is cheap and it cushions the reputation hit when a campaign underperforms.

This is the part Blitz handles inside grobot Command Center (domain and mailbox provisioning, warmup, rotation across mailboxes and throttling) so the sending shape stays inside these limits without anyone tracking it by hand. Sends are included in the license and never metered.

Before Your First Campaign

• Verify SPF, DKIM and DMARC actually pass by sending yourself a message and reading the headers. Publishing a record is not the same as it working.
• Connect Postmaster Tools for every sending domain. It is free and it is the only authoritative view of your Gmail reputation.
• Seed-test into Gmail, Outlook and a corporate Microsoft 365 tenant. Microsoft filters differently enough that Gmail-only testing will mislead you.
• Verify the list immediately before send, not at import.

Once it is running, the ongoing discipline (complaint rates, bounce thresholds, what to do when reputation slips) is the deliverability guide.