IP Warming

IP warming is a way to establish a new IP address’s reputation by gradually scaling up its email sending volume. Email service providers, like Gmail, Outlook, Yahoo, etc., want to prevent their clients from being bombarded with spam. For that reason, new IP addresses that start sending emails en masse undergo careful moderation.

Check out the video below to find out why it's essential to warm up a new email address.

Why should you do IP warming?

IP warming is necessary for a good delivery of email campaigns sent from a new IP address. Without warming up your IP, your emails are more likely to bounce or land in the spam folder. ESPs need to see a record of your IP consistently sending quality emails. ESPs analyze your behavior as a sender and your subscribers’ engagement. Before your IP meets their criteria, they will be suspicious of emails from a new IP address.

The essential goal of IP warming is to improve your sender reputation. With a bad reputation, your emails may land in the spam folder or, even worse, your IP may get blacklisted. With a good reputation, your messages have more chances to be delivered to recipients’ inboxes.

How long does IP warming take?

IP warming may take up to 4-8 weeks before you earn a good reputation from ESPs. It depends on the volume of emails you plan to send and your subscriber engagement level.

Things may get worse if you try to send emails en masse right away. This approach can damage your sender reputation and result in severe deliverability issues, like hard bounces. Additionally, recovering from one of these issues can take months.

It’s best to send emails to users that are most likely to engage with your emails. On the contrary, it’s a bad practice to send emails infrequently, less than once a week because it will take more time to build a positive sender reputation.

To speed things up, start your IP warming process by sending your emails to subscribers that have opted-in recently or engaged with a few of your recent messages. Let’s find out what you should do to warm-up your IP address.

How to Do IP Warming

Let’s take a look at a two-week IP warming schedule for a large email list of five million email addresses as an example. You need to increase your email sending volume daily, like the following:

• Day 1 — 200 emails;
• Day 2 — 500 emails;
• Day 3 — 1,000 emails;
• Day 4 — 2,000 emails;
• Day 5 — 5,000 emails;
• Day 6 — 10,000 emails;
• Day 7 — 20,000 emails;
• Day 8 — 40,000 emails;
• Day 9 — 100,000 emails;
• Day 10 — 250,000 emails;
• Day 11 — 500,000 emails;
• Day 12 — 1,000,000 emails;
• Day 13 — 2,000,000 emails;
• Day 14 — 5,000,000 emails.

Use this pattern even if your email list is smaller than the example. You also need to carefully choose the recipients for each stage of warming up your IP:

• During weeks 1-2 send to your most active subscribers who have opened or clicked your emails in the past month;
• During weeks 3-4 involve subscribers who have opened or clicked your messages in the past two months;
• Avoid sending emails to subscribers who have been idle during the past three months. Only send emails to these subscribers after six weeks pass.

Now that you’ve learned how to warm-up your IP, let’s finish this guide with some best practices.

We’ve collected five actionable tips that will help you warm-up your IP address as quickly as possible. Here they are:

1. Authenticate your emails. You need to set up DKIM and SPF records so that email service providers give your emails more credit. Here are guides to set up DKIM and SPF authentication records with SendPulse.
2. Verify your email list. Use an email verifier to run your list through various validation checks and eliminate all inactive email addresses. Remember, sending emails to invalid email addresses results in more bounces that damage your sender reputation.
3. Maintain a healthy email list. During your IP warming, some users will unsubscribe or mark your email as spam, which is normal. However, it’s best to immediately remove unsubscribers from your mailing list to avoid sending any more emails by accident. Luckily, SendPulse automatically adds these users to a suppression list, so you won’t be able to send more messages anyway.
4. Send the most engaging types of emails. Educational and entertaining content shows better engagement in email marketing compared to promotional emails. For instance, you can send curated newsletters with the latest news and high-quality content related to your industry. You can also send marketing emails with valuable offers and discounts. Anyway, your emails should be personalized, eye-catching, and give subscribers a positive experience.
5. Closely monitor your email metrics as you go. It’s necessary to analyze your open rates, CTR, bounce rate, unsubscribe rate, and spam complaints. A sudden drop in open rates, for instance, may tell you that your subject line is not eye-catching. A more severe issue, like a lot of unsubscribes, indicates there is something wrong with your email content. It helps if you pause your IP warming, find out the reason for the drop in the metrics, fix the issue, and only then continue to increase your sending volume.

Congratulations, now you know the basics of IP warming, so you will avoid mistakes that cost you time, money, and reputation.

Last Updated: 22.03.2023