IP Warm-Up is Key to Building Sender Reputation in Email Marketing – Here’s How it’s Done

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As an email marketer, you work in a highly competitive sector. With so many brands vying for the attention of your target consumers, you need to give yourself every chance of success eliminating any possible chance of deliverability issues.

To ensure that you maintain high deliverability, you will need a solid sender reputation, and that’s something that your new IP address doesn’t have. Fortunately, it is possible to build your sender reputation and improve your deliverability through IP warm-up.

But what is IP warm-up, and how does it benefit your sender reputation?

What is the IP warm-up process?

The IP warm-up process is an email-sending practice that helps mail providers and ISPs (Internet Service Providers) become accustomed to your sending habits. It involves gradually increasing one’s sending volumes over a set period and typically takes between 4 and 8 weeks. It is an important aspect of the preparation stage which precedes the commencement of an email marketing campaign.

Although IP warm-up is highly important, it is not relevant to all senders. The process is a priority for senders using dedicated IP addresses specifically. Dedicated IPs are ones intended to be used exclusively by one sender, and exist in opposition to shared IP addresses, which allow multiple users to send emails from the same IP.

Dedicated IP addresses are created new for every sender, and this brings certain implications with it. Chiefly, since a new dedicated IP has no previous sending history, it is impossible ISPs and mail providers to accurately gauge the reputation of the sender. 

Typically, IP addresses are assigned a reputation score – a number from 0 to 100 that indicates trustworthiness – by ISPs, and this is used to determine whether or not mail is delivered to its recipient’s inbox. However, new IPs have no such score.

As such, marketers who wish to use dedicated IPs must build up their sender reputations before attempting to enact campaigns at any notable scale.

Why is IP warm-up so important for sender reputation?

IP warm-up is essential to building up one’s sender reputation and ultimately getting mail delivered consistently.

Since new dedicated IP addresses have no sender score associated with them, they are subject to sending limits. That means that after reaching a certain threshold with a specific mailbox provider, any emails sent to that provider will either be routed to the spam folders of recipients or blocked completely.

Having one’s messages blocked or classified as spam can have a devastating impact on the outcome of an email campaign. Moreover, it can result in a considerable loss for the brand. Naturally, this is something every marketing wants to avoid, and IP warm-up is the way to do this.

By helping them to build up their score among ISPs and mailbox providers, IP warm-up enables a sender to achieve a good sender reputation. This corresponds to high deliverability, and a better return on investment when campaigns are eventually rolled out.

How to warm up an IP address

IP warm-up is a delicate process, and it should be handled with care.

To begin warming up a new IP address, you should begin by deciding on a target email volume that will be representative of your send-outs going forward. Then, on the first day, you should begin by sending the maximum possible volume you can without breaching limits.

In the early weeks of IP warm-up, senders typically double their volumes each day. However, as the process progresses the increases should decrease in order to maintain a gradual ramp-up. Throughout the IP warm-up process, it is advisable to spread your sends out across each day to avoid issues. This means that IP warm-up must be closely managed when done manually.

Alternatively, if manual IP warm-up is too labor-intensive, it’s possible to automate the process. With an email marketing platform offered by an ESP (Email Service Provider), you can set your target volume and allow the software to do the rest. These platforms will throttle emails to avoid breaching sending caps and will spread out sends to ensure optimal results.

Regardless of how you choose to perform IP warm-up, it is crucial that you remain consistent after the process is finished in order to avoid future deliverability problems. This means that your send-outs should follow a strict pattern after warm-up, both in terms of volume and frequency.


Sender reputation is a highly important aspect of email marketing because it plays a major role in your ability to land in your subscribers’ inboxes. For that reason, it is essential that you take every measure to ensure your reputation is in a good place. When using a new dedicated IP, that means performing IP warm-up.

Achieving success through email marketing can be challenging, but by taking an organized approach to IP warm-up, you can ensure that your campaign gets off on the right foot.


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