I’m working on a client’s new email server today and it reminded me how much conflicting advice there is around warming up a new sending IP.
Some of it is decent, some of it is wildly aggressive, and a lot of the warm-up charts floating around seem to assume every sender, list and mailbox provider is going to behave the same way.
We’ve never really treated it like that.
When we bring a brand new IP online, we start tiny. Usually around 20–30 emails a day.
That might be friends/family at the very start who we know will actually receive and interact with the mail, or if the client already has a decent list, we’ll use a very small group of their most engaged people.
Before any of that though, the setup needs to be right. SPF, DKIM, DMARC, PTR/rDNS, HELO, Return-Path, tracking domains etc.
No point trying to warm an IP when you’ve got a basic config issue working against you.
From there we use a pretty simple rule.
We never increase volume by more than 30% in a day, and we only increase it if at least 90% of the previous send successfully delivered.
If it doesn’t hit that, the volume doesn’t go up.
That’s it really.
Once everything is running properly, the ramp happens automatically based on the previous day’s delivery.
What’s interesting is how quickly it starts to snowball.
Starting at 20 emails sounds ridiculously low, but if you managed to increase by the full 30% every day, you’d be roughly at:
Day 1: 20
Day 5: 57
Day 10: 212
Day 15: 788
Day 20: 2,924
Day 25: 10,858
Day 30: 40,308
Obviously you’re not guaranteed to get that increase every day.
If Microsoft starts deferring more mail, Gmail looks unhappy, complaints creep up or delivery drops below the threshold, then you hold it.
That’s the bit I think gets missed when people follow fixed warm-up schedules.
A spreadsheet might tell you to send 10k tomorrow, but the receiving networks might be telling you something completely different.
We’d rather listen to that.
We also keep the early audience as clean as possible. Recent subscribers, customers, people who click, reply, purchase or actually use the product/site.
The last thing I’d want to do with a fresh IP is chuck a load of old inactive contacts at it just to hit a target number.
Another thing worth remembering is that the IP isn’t working in isolation either.
Domain reputation matters, sending patterns matter, complaints matter, content matters and the quality of the list matters.
If you change the IP, domain and traffic pattern all at once, and something goes wrong, it becomes much harder to work out what caused it.
So for us it’s basically:
Start at 20–30 → use the strongest recipients first → never increase more than 30% → only increase if 90%+ delivered → let it ramp automatically when the numbers are healthy.
The first few days feel painfully slow, but that’s kind of the point.
You don’t need to force the volume early on. Once the compounding kicks in, it grows pretty quickly anyway.
There’s no benefit in getting to full volume a few days earlier if you damage the reputation on the way there.
Source: r/emaildeliverability · by /u/EmailFoundry