Do you know how to go about warming up a new IP address or mailing list? When you acquire a new IP address it’s very important that you warm up that IP address properly, and follow an IP address warm-up schedule. What this means is starting out using that IP address slowly, sending out only an increasing fraction of your total volume of email over time, rather than launching full throttle on day one. This is because grabbing a new IP address and immediately blasting thousands and thousands of pieces of email from it is what spammers do – and you don’t want the volume of email you send to make you look like a spammer. It’s true that the content of your email is also very important in terms of how spammy your email may seem, but in the beginning stages of using a new IP address, when that IP address or mailing list has no reputation with the inbox providers and so what will flow from it is unknown to them, the volume of email that you send is just as important. This is definitely a case where moderation is the key, and discretion is the better part of deliverability.

We’re going to get to that warm-up schedule in a moment, but first here are some general guidelines to follow in terms of the email that you should send through your new IP address or IP addresses during the warm-up period. While of course doing everything 100% will help ensure the most successful warm up, and greatest deliverability, and the best reputation for your new IP address or mailing list, do as much as is practical for your particular situation.

• Make sure that all of your email authentication is set up, and set up properly.
• Remove any and all subscribers who have not opened your email in the past 30 days, or across the last three sends (put them on a separate re-engagement list, which you will send from your old IP address, if any).
• If possible send only to your most engaged subscribers for the first two weeks of your warm-up period. These are the people who routinely open your email and, ideally, click on links contained therein.
• If you have already been sending to your mailing list through other IP addresses, continue to do so while gradually migrating your list over to the new IP address, moving the most engaged of your subscribers over to the new IP address before less engaged ones.
• Make the email you send during the initial warm-up period as plain as possible: limit images, limit links, limit code. The goal is to make as much of your email as possible get to the inbox so that the inbox providers see that it’s going there and deserves to be there while you build up your reputation. That said, if you can do so without being disingenuous, do occasionally include a link with a CTA (call to action) when sending to your most highly engaged subscribers, as when subscribers click on your links in your email it helps boost your email reputation.
• Be sure to send consistently from your new IP address every single day for the entire 30 day period.

NOTE: We recommend that if you ultimately want to send more than 15,000 pieces of email a day, you should have at least 2 dedicated IP addresses, and anything over 1,000,000 pieces of email a day should have at least 3 dedicated IP addresses. This is just a general guideline, your email service provider (ESP) may have other guidelines.

IP Address Warm Up Schedule

The basic mechanics of warming up a new IP address or new IP addresses is that you spread out your sending across days and weeks. Ideally this means that you will send to a fractional segment of your email list on day 1, and to a larger (possibly different if you need to do that in order to get email to everyone on your list within a certain time period) segment on day 2, and so on. Of course to some extent, and by necessity, your IP address warm up schedule will be influenced by how large your mailing list is. After all, if you have a mailing list of millions (or several mailing lists totaling millions) it may not be practical to spread sending to the full list across weeks, or to put off being able to send to all of them at once for several weeks.

Generally speaking, you should warm up your IP address by sending according to the following schedule for the first 15 days, and if you have not exhausted your mailing list by then (i.e. still have email addresses to which you have not sent email) then from day 15 forward double the number of email addresses to which you send each day, until you have sent to all of your email addresses. If sending volume permits, you can add back in email addresses to which you have already sent something during the warm-up period.

Remember that the below volume numbers are total number of emails sent to all inbox providers combined. So for example on day 6 you should aim to send no more than (but also not much less than) 10,000 pieces of email total.

At the same time it is very important that during the first week you not send more than 1,000 pieces of email in an hour to any one single inbox provider. So, using day 6 as an example again, you will aim to send 10,000 pieces of email total, but no more than 1,000 in an hour to, for example, Gmail. During week 2 you can double that to 2,000 pieces in an hour to a single inbox provider, and then continue doubling that amount each week.

Here’s the warm-up schedule:

Recommended IP Address Warm-up Schedule