How to warm up a new email sending domain

Why warm-up exists

Spammers register new domains and blast mail the same day. Providers know this, so a brand-new domain that suddenly sends thousands of messages looks the same. Your reputation starts neutral and grows as providers see steady volumes, low bounces, low complaints and people opening or replying.

Before you send anything

1. Set up SPF, DKIM and DMARC for the domain, and check them.
2. Use a subdomain for each kind of mail (for example mail.example.com for receipts and news.example.com for newsletters), so a problem in one does not affect the other.
3. Make sure the From address can receive replies. A mailbox that never answers looks like a bot.

A cautious ramp

There is no official schedule, and providers publish none. This is a careful one that works for most small senders; slow down if anything below goes wrong.

• Week 1: a few dozen messages a day, to people who know you and will open or reply: your team, recent customers, friends. Ask some to reply.
• Week 2: a few hundred a day, to your most engaged contacts.
• Weeks 3 and 4: double every few days, adding less engaged contacts last.
• After a month: your full list, but never a sudden jump of ten times your usual volume.

What to watch

• Bounces. Keep hard bounces well under 2% and remove bad addresses straight away.
• Complaints. Keep them under 0.1%. If they rise, stop and look at who you are mailing.
• Where it lands. Send tests to seed addresses at Gmail, Outlook and Yahoo throughout, and look in spam folders.
• Google Postmaster Tools. Once you send enough to Gmail, your domain reputation appears there.

Mistakes that undo a warm-up

• Mailing a purchased or very old list on day one.
• Sending a large first campaign because it is “just a test”.
• Ignoring bounces and keeping them on the list.
• Pausing for weeks, then restarting at full volume.
• Fake opens and replies from your own accounts: providers can spot it, and it teaches you nothing about real recipients.