Warming up a new sending domain means ramping volume slowly, to your most engaged contacts first, so mailbox providers learn to trust the domain. Done well, a fresh domain reaches usable trust in three to four weeks. Done badly, it gets filtered before you start.
Before you start
Publish SPF, DKIM and DMARC for the new domain and verify the records resolve. Confirm DMARC is at p=none with reporting on so you can see what receivers think. Decide whether the domain is dedicated to sending (recommended) and pick a sensible subdomain such as mail.yourbrand.com.
Pull a clean warm-up audience. The most engaged 1 to 5% of your file: people who opened or clicked something in the last 30 days. Suppress everything else for the first two weeks.
A sample 4-week ramp schedule
This is a conservative schedule for a fresh dedicated domain sending one campaign a day. Adjust upward only if engagement is strong and bounces and complaints stay clean.
- Days 1 to 3: 1,000 to 2,000 highly engaged contacts per day, one send daily.
- Days 4 to 7: ramp to 5,000 to 10,000 per day, still top-decile engagement only.
- Week 2: 25,000 then 50,000 per day; introduce the next engagement tier.
- Week 3: 100,000 to 250,000 per day; broaden the audience further.
- Week 4: full-volume campaigns; continue to suppress repeat non-openers.
Engagement, not just volume
Mailbox providers do not just count messages; they watch what happens to them. Warm-up content should be genuinely valuable to the people you send to: a useful update, a high-converting offer, an editorial piece they expect. Avoid pure prospecting blasts and anything that tends to produce complaints.
What to do if reputation slips
If bounce rate exceeds 2% or complaint rate exceeds 0.1% on any send, pause for 24 to 48 hours, drop back two ramp steps, and resume only with your most engaged audience. Investigate the spike: a single import of dirty addresses can undo a week of warming.
After warm-up
A warmed domain is not warm forever. Sustained volume keeps reputation high; long silences let it drift. Plan for ongoing cadence, and if you stop sending for a few weeks, ramp back up gently rather than firing at full volume.
Frequently asked questions
How long does it take to warm up a new email domain?
Three to four weeks is the safe range for most senders. Aggressive ramps can shave a week off but rarely save time once you account for reputation damage from going too fast.
Can I send the same email to multiple domains during warm-up?
Yes. Many large senders warm several domains in parallel by rotating sends. Each domain still needs its own engaged audience and its own gradual ramp.
Should I warm up a domain even if my IP is shared?
Yes. Domain reputation is now more important than IP reputation for most senders, and a new domain on a warm shared IP still needs to earn trust.