How to Warm Up a New Domain for Cold Email, Step by Step

Warm-up on a domain with broken setup is wasted effort. Complete this list first:

1. Buy a domain separate from your main one. Don't risk your company's primary domain. The secondary domains guide explains how to choose and set them up.
2. Create real mailboxes with a business email provider, using a real sender name.
3. Publish SPF, DKIM and DMARC records for the domain, and confirm each passes. The authentication checklist walks through it.
4. Point the domain to a simple website or redirect to your main site, so a recipient who checks it sees something legitimate.
5. Add a proper signature with your name, company and mailing address, which sending rules require for commercial email.
6. Send a test to accounts at several providers and check that the message lands in the inbox and shows authentication as passing.

There's no official schedule, so treat every number below as an example, not a rule. The principle is slow, steady growth with real engagement.

Say you have three mailboxes on the new domain. One way to ramp them:

1. Week 1: each mailbox sends about 5 emails a day to real contacts who are likely to reply, and you answer every reply.
2. Week 2: raise each mailbox to about 10 a day, still mostly to people who know you or expect the message.
3. Week 3: raise each mailbox to about 15 a day, then run a placement test at the end of the week.
4. Week 4: if placement and bounces look healthy, start cold sends from each mailbox at a low daily cap, such as 10 a day, while warm-up traffic keeps running.
5. After that: raise the cold cap in small steps, one mailbox at a time, and only after a clean week.

If any week shows spam placement or rising bounces, hold at the current volume or step back before you continue. A slower ramp costs you a few days, while a damaged domain can cost you the domain.

Follow these rules while ramping:

• Send to real people who will reply. Colleagues, friendly contacts and other domains you control can start real conversations.
• Reply to those replies. Two-way threads show that the mailbox behaves like a human.
• Keep the pattern steady. Sudden jumps in volume look like a compromised account.
• Pause if things worsen. If messages start landing in spam or bounces rise, stop increasing and find the cause.
• Keep warm-up running alongside early cold sends, at low volume. Don't switch it off the day cold campaigns begin, and don't jump to full volume the same week.

Warm-up tools automate the exchange of emails between mailboxes in a network, generating opens and replies so that a mailbox builds a track record while you're not sending real campaigns. They save time, but they aren't magic. Mailbox providers evaluate many signals, and automated interaction is only a small part.

MailReach fits when you want automated warm-up and reputation monitoring in one place. InboxAlly fits a different case: when a domain's placement has already suffered and you're trying to repair it. If you're choosing between them, the InboxAlly vs MailReach vs Warmup Inbox comparison sets out the differences.

A tool doesn't replace the basics. Authentication, clean lists, relevant messages and modest volumes matter more than the warm-up service.

Check these signals weekly:

• Inbox placement tests: send from the mailbox to test addresses at major providers and see whether messages reach the inbox, promotions tab or spam.
• Bounce rate: a rising bounce rate points to list problems or reputation damage.
• Replies: real replies from real recipients are a strong sign.
• Provider dashboards: if you send to a large provider, its free sender tools can show reputation trends once you have enough volume.
• Complaints: any spam complaint is worth investigating immediately.

Ignore raw open rates. Open rates from newsletter benchmarks aren't a target for cold outreach, and image-based open tracking is unreliable, since many mail apps load images automatically.

Avoid these:

• Sending cold campaigns from day one. A new domain with no history and a large list of strangers is a setup that makes spam placement likely.
• Buying a list and hoping. Poor list quality is a quick route to bounces and complaints. Verify addresses before you send.
• Using the primary domain. If it gets flagged, your everyday company email suffers too.
• Ignoring authentication errors. A failed DKIM or a missing DMARC record undoes weeks of warm-up.
• Scaling every mailbox at the same time. Add capacity gradually, one mailbox at a time, and check results before adding the next.

Once the domain is running, keep an eye on it. How to check if your sending domain is blacklisted covers what to do if something goes wrong, and Lemlist vs Instantly vs Smartlead helps with choosing sending software.