IP Warm Up

The Internet Protocol (IP) warm-up process ensures that digital communications end up in the inbox instead of the spam folder.  

Unsolicited messages, more commonly known as spam, have been around ever since the internet became available for commercial use. Due to their pervasiveness over the years, IP warming has become a necessary process that ensures great email deliverability in the future. 

What Is an IP Warm Up?

An IP warm up refers to the process of establishing a positive email sender reputation with internet service providers. It entails sending a low volume of emails from the new IP address, which senders can gradually ramp up over time until they reach their targeted volume. 

For example, an IP warming schedule for an email list with millions of subscribers might start with 200 emails on day one. The following day, the limit can be increased to 500 emails. The day after that, emails can be ramped up to 1,000.

It might take 4 to 8 weeks before senders can earn a positive reputation and perhaps 8 to 12 weeks before they can achieve full deliverability. Ultimately, it depends on the sender’s target volume and engagement rates.

IP warming is a time-consuming process, but it’s a necessary one that can prevent potential deliverability issues.

Who Needs to Warm Up their IP?

IP warming isn’t for everybody. The warm-up process is only necessary for those who are using dedicated IP addresses to send emails in bulk. If a business decides to hire an email marketing service, then the process won’t be necessary. In this case, the deliverability of their email campaigns will depend largely on the reputation of the shared IP address, as well as the prior campaigns. 

Internet Service Providers (ISPs) won’t be concerned if a business isn’t sending large volumes of emails monthly. Thus, if a business isn’t sending tens of thousands of emails per month, then IP warming won’t be necessary. 

Types of IP Warm Ups

An IP warm up strategy varies greatly from user to user. That’s because each one has different goals and needs that might affect their strategy. In general, there are two ways to approach IP warming: manual and automation.


Senders can manually warm up their IP addresses. They have to come up with a strategy and a schedule based on their goals. For example, they can set hourly or daily sending limits. Since the process isn’t automated, they’ll have to do it manually as they gradually increase the volume of emails. 


There are email warm-up tools that can automate the IP warming process. They can improve the email sending reputation without requiring as much work as the manual process. 

Why Is IP Warming Necessary?

New IP addresses are more prone to having their emails blocked or blacklisted because of the lack of sender history. The warm-up process enables senders to improve their reputation, making service providers less suspicious of emails coming from their IP addresses. However, if senders fail to warm up an IP, they could face a range of consequences.

Here are a few of those issues:

  • Slow delivery speed

Failing to warm up an IP can lead to slow email delivery speeds. For instance, a marketer intends to send 10,000 emails to its subscribers without warming up their IP. Only 2,000 of those emails could be sent within the first hour.  

ISPs will even monitor how recipients engage with the emails. They will pay attention to spam reports, open rates, click rates, and more. They will use the metrics to determine what to do with the remaining emails.

If the emails have poor engagement rates and have high spam reports, the rest of the emails could be sent as spam. Until the sender builds up a good reputation with ISPs, emails could be delayed or sent to spam.

  • Getting blacklisted

Once an IP address ends up on a blacklist, all emails will no longer be delivered. Senders seldom receive notifications of getting blacklisted. They’ll have to manually look up their IP addresses on published blacklists to check the status of their IPs.

Recovering a blacklisted IP address is nearly impossible. It would be easier to establish a positive reputation using a new IP address. 

About the Author
Koba Molenaar brings nearly a decade of rich experience in content writing, specializing in digital marketing, branding, SaaS, and eCommerce. Her passion for helping brands, from solopreneurs to established companies, connect with their audiences shines through her work. As a member of the Golden Key International Honor Society, Koba’s commitment to excellence is evident in her work, showcasing her as a relatable and knowledgeable voice in the industry.