Cold email setup with secondary domains and warmup: the stack we teach

Sunny Ray · Oct 15, 2026 · 7 min read

The cold email setup we teach is simple to describe: never send from your main domain, buy five or six alternate domains, build about 100 mailboxes on them, warm those mailboxes for two weeks, then run a three-touch sequence with no links in it. That's the stack we walked through at our Relationship Engine session on October 9, with about 115 people invited.

If you're asking whether you should cold email from your main domain: no. If you're asking how long to warm up: about two weeks before real volume. If you're asking about links: leave them out. The rest of this post explains each piece, and what happened when Emiliano tested a tool that skipped all of it.

Why this matters more than the copy

I opened that session with the reason people do cold email at all. Most of us start with referrals. They close well and they feel safe. But in my words that morning:

But the problem with just relying on referrals is that you end up in a local maximum. You have a hard time finding your global maximum.

Cold outreach is how you get out of your own network. But it only works if your emails land in the inbox. Great copy in a spam folder is no copy at all. So before anyone writes a word, the plumbing has to be right.

Never send from your main domain

Your main domain is the one your company email runs on. Your invoices, your investor updates, your customer support. If cold outreach damages its reputation, every one of those emails starts landing in spam too.

So the rule has no exceptions: the main domain is never used for outreach. You send from alternate domains that look related to your brand but are separate. If one of them gets burned, you lose a sending domain, not your company's ability to email its customers.

Domains and mailboxes

The setup we teach is five to six alternate domains with about 100 mailboxes built on them. Spreading volume across many mailboxes keeps each one sending a modest, human-looking number of emails a day, which is what inbox providers expect from a real person.

On a different call that same week we described the per-mailbox side of this: up to 20 mailboxes per domain, and a handful of emails per mailbox per day, somewhere between 4 and 10. The pattern is the same. Lots of mailboxes, each one sending gently.

The tools in the stack, as we listed them on the session: Apollo for leads, Million Verifier for cleaning the list, SendGrid and Namecheap for sending and domains. Verifying the list matters as much as the domains. Bounces are one of the fastest ways to hurt a fresh mailbox.

Warmup before volume

A new mailbox has no history. If it starts sending hundreds of cold emails on day one, it looks exactly like a spammer, because that's what spammers do. Warmup builds a history first: the mailbox sends and receives normal-looking email at gradually increasing volume.

We warm mailboxes for about two weeks before they send campaigns. Once they're warm, the setup scales to about 1,000 emails a day within one to two weeks. Two weeks of patience buys you a sending system that lasts.

Three touches, no links

The sequence is three touches, A/B tested. Not seven. Three is enough to catch people who missed the first email without becoming the person who won't stop emailing.

And no URLs in the emails. Links are one of the things spam filters weigh most heavily in cold email, especially from newer domains. You don't need them. If someone wants to know more, they'll reply, and a reply is what you wanted anyway.

Campaigns are written per audience: one for investors, one for partners, one for customers. Same infrastructure, different words.

One inbox for replies

With 100 mailboxes, replies land in 100 places. Nobody can check that by hand. So every positive reply gets consolidated into one unified inbox, and bookings go through a scheduling page with a few qualifying questions.

At peak, I was averaging 20 to 25 leads a day from my own campaigns. The target for a client is more like 4 to 5 a day. Either number is impossible to manage without one place to read and answer them.

What happens when you skip it

During the session, an attendee brought up an auto-drafting cold email tool he'd tried. Emiliano had tested the same one. His report was blunt.

It was easy to launch. About 30 minutes, from his phone. And it spammed his contacts, with a reply rate of about 0.05%.

That's what the shortcut costs. No warm mailboxes, no separate domains, no offer worth replying to. Just volume pointed at people's inboxes. Fast to start and close to useless, and you can do real damage to whatever domain it sends from.

The difference between that and what we run isn't the AI. Everybody has AI now. It's the boring parts: the domains, the warmup, the list cleaning, and an invite people want to say yes to.

The offer still matters

Infrastructure gets you into the inbox. It doesn't make anyone reply. The reason our setup works is the email carries an invitation to come on a show, not a sales pitch. That framing is why a warm invite inside a cold email tests so much better than a standard cold pitch. You're giving before you ask.

Put a hard pitch on perfect infrastructure and you'll get delivered and ignored. Put a good invite on bad infrastructure and nobody sees it. You need both.

The mistakes we see most

When a founder tells me cold email doesn't work, it's usually one of these. They sent from the main domain and now their own invoices land in spam. They skipped warmup because they were in a hurry. They uploaded a list nobody verified, and the bounces flagged their new mailboxes in the first week. Or they wrote a seven-step sequence with a link in every email.

Every one of those is a setup problem, not a message problem. And every one is avoidable before you send a single email.

The fix is boring and it works: separate domains, verified lists, patience during warmup, short sequences, no links. Get those right once and you stop thinking about them. Get them wrong and you'll spend months wondering why a good offer gets no replies.

Doing it yourself vs. having it done

You can build all of this yourself. Buy the domains, set up DNS, create the mailboxes, run warmup, clean lists, write sequences, wire up a unified inbox. It's a few weeks of work and some ongoing care. Plenty of founders do it.

Or you can skip the setup. gtm showrunner sends from separate warmed domains so your main domain stays clean, and the Growth plan includes our warmed mailboxes, so there's no two-week wait on your side. Every invite and reply is drafted and waits for your approval. If you'd rather hand the whole thing over, our team at GTM Ventures runs it for you.

Either way, the six layers are the same: domains, mailboxes, warmup, list, sequence, inbox. You can see how they fit together on how we work.

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