How to Warm Up a New Domain for Cold Email (The Schedule We Actually Use)

A practical, day-by-day plan for warming up a new sending domain: DNS setup, a slow ramp, what Google actually requires, and the bounce mistakes that undo all the work.

I'm the founder of Selamly. Every account we open gets new sending domains and mailboxes, so warming them up is something we do every week, not once. This is the exact process we use, including the numbers in our own ramp. Google's rules quoted below are from Google's own help pages, checked in October 2026.

Why a new domain needs warming up

Mailbox providers decide where your email lands mostly on reputation, and a brand-new domain has none. If it suddenly sends hundreds of emails to strangers, that looks exactly like a spammer who just bought a domain. Warming up means building a short, clean history first: small volume, real conversations, almost no bounces or spam reports, then growing slowly.

Google says it plainly in its sender guidelines: start with a low volume, increase it slowly over time, and avoid sudden spikes if you don't have a history of sending large volumes. Gmail also treats domains without a sending history as new, and its enforcement for new domains moves faster. In other words, the first weeks matter most.

Step 0: never warm up your main domain

Cold email always carries some risk. If it goes wrong on your main domain, your invoices, password resets and replies to customers start landing in spam too. So we never send cold email from a customer's main domain.

• Register a separate domain that is clearly yours, like get[yourbrand].com or try[yourbrand].com, and redirect it to your real website so anyone who checks it lands somewhere real.
• Open 2 to 3 mailboxes on it in the name of a real person (first name, first.last, and an initial-based address work well).
• Use a proper mailbox provider such as Google Workspace or Microsoft 365, not a bulk-mail server.
• If you stop doing outreach, retire the domain. Your main domain was never involved.

Step 1: DNS before the first email

Set these up on day 0. Google requires SPF or DKIM for everyone, and SPF, DKIM and DMARC together for bulk senders (more than 5,000 messages a day to Gmail). Cold email rarely reaches that volume, but there is no reason not to do all three.

Google also asks every sender to use TLS and to keep the spam rate shown in Postmaster Tools below 0.3%, ideally below 0.1%. Add your new domain to Google Postmaster Tools on day 0 so you can see it once there's enough volume.

Step 2: the ramp (our actual schedule)

Each mailbox runs two things in parallel: warm-up emails (exchanged with other real mailboxes, opened and replied to) and, after a few days, a handful of real outreach emails. Here is the per-mailbox schedule we use. Warm-up keeps running the whole time.

With 3 mailboxes that's a few emails a day in the first week and full volume in about four weeks. It feels slow. It's meant to: a domain that burns in week one can't be repaired by sending more.

Step 3: protect the ramp from bounces

Bounces are the fastest way to undo a warm-up. A new domain with a high bounce rate looks like it's mailing a bought list, which is usually what it is. What we learned the hard way:

• Only email addresses the company publishes itself, on its own website. Bought and guessed addresses bounce far more.
• Verify every address before the first email, and stop the sequence the moment one bounces.
• Verification is not perfect. Some Google Workspace domains accept the address during the check and bounce the email later, and some Microsoft 365 servers refuse checks entirely, so a checker can say "valid" or "unknown" for an address that will bounce. Keep a little margin in your volume for this.
• Read the bounce messages. "Address not found" means a bad list; "access denied" or "relay denied" often means the receiving server blocks outside senders, which no checker sees.

Step 4: write emails that get replies, not just opens

Warm-up builds a reputation; your real emails either keep it or spend it. Replies are the strongest positive signal, and "report spam" is the strongest negative one. In practice that means short, plain-text emails written for one specific company, no attachments, no link shorteners, a real name and signature, and an easy way to opt out. Every opt-out is honored immediately.

Signs your warm-up is going wrong

• Bounces above a couple of percent: pause and fix your list before sending more.
• Replies drop to zero after a good start: check whether you've moved to spam (send a test to a personal Gmail and Outlook address).
• Postmaster Tools shows your spam rate climbing towards 0.3%: cut volume and look at what changed.
• Mailbox provider warnings or temporary blocks (Gmail's 4.7.x "rate limited" errors): slow down; don't push through.

Doing it yourself vs having it done

You can do all of this yourself with a domain registrar, Google Workspace and a warm-up tool. Budget about an hour for setup and a few minutes a day for monitoring. Selamly does it for you: we register the domain, open the mailboxes, set the DNS, run the warm-up and the ramp above, and only start real outreach when the mailboxes are ready.