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Ashley GrantNov 29, 2023 7:14:23 AM7 min read

IP Warmup - Why is it so Important?

There’s something that is often overlooked in email marketing. Can you guess what it is? If you said IP warmup, you’re right! You may have guessed it because of the title of this post, or because an internet search landed you on this page.

The truth is, you might not know what IP warmup even is. So that’s what we’re going to break down. We’ll answer:

-- What is IP warmup?

-- Why is it so critical?

-- What are the benefits of it?

-- And, what are the best practices for doing it the right way?

Wait, What Is IP Warmup Exactly?

Open your textbooks to page five. Totally kidding, but we do need to break this down so that it’s 100% clear since a lot of people overlook this important step in email marketing.

First, IP in this case refers to internet protocol. And, an IP address is basically just the unique numeric identifier assigned to a device that connects to a network or the internet.

An IP warmup is the process of gradually increasing the number of emails sent from a new IP address to build up its reputation and avoid getting blocked or flagged as spam.

When you start sending emails from a brand new IP address, email providers don't know anything about its reputation yet. If you suddenly send a ton of emails from this unknown IP, many will likely get blocked or filtered as spam.

IP warmup allows you to safely build up the IP's reputation over time by gradually increasing the volume of emails sent. As the IP establishes a good sending history, deliverability will improve and more emails will make it to the inbox.

What IP warmup is NOT:

- It's not instantly blasting out mass emails from a new IP. That's a surefire way to get blacklisted.

- It's not just setting a low send volume and leaving it. The volume must be progressively increased.

- It's not something that's done in a day or two. A proper warmup takes weeks or months.

- It's not applicable once an IP has been used for email already. Warmup is only for brand new, unused IPs.

So in summary, IP warmup is taking things slowly and steadily to build trust and reputation for long-term deliverability. It's an essential process for any new email IP address.

The Critical Importance of IP Warmup

Proper IP warmup is crucial because inbox providers are cautious of unknown sending IPs with no behavioral data. Sending large volumes too quickly can appear suspicious and risk temporary or permanent blocking. Warming up new IPs slowly demonstrates responsible sending patterns and garners positive engagement signals to establish sender reputation. This minimizes the likelihood of deliverability issues. Prioritizing IP warmup protects sender credibility and ensures reliable inbox delivery.

Reaping the Benefits of IP Warmup

Taking the time to go through the IP warmup process provides many advantages. When you go about things the right way, here are just a few things you will enjoy:

  1. You’ll avoid the dreaded spam folder filtering and blacklisting risks
  2. You’ll instantly start building positive sender reputation with inbox providers
  3. Gaining insights on audience engagement and response will be that much easier
  4. Your emails will have a better shot at long-term deliverability - when you don’t look like a spammer, you’re more likely to enjoy whitelisting
  5. Because you didn’t slide into the inbox without being invited, email engagement should be improved too
  6. Finally, you’ll have the opportunity to identify and fix potential issues early

Proper IP warmup pays dividends through improved deliverability, higher open and click rates, and greater subscriber trust.

IP Warmup Best Practices


So how does one go about IP warmup? Do you have to stretch first? Get plenty of hydration? Nah! But, there are some key tips you should stick in your back pocket if you hope to have  effective IP warmup.

It’s a slow burn

Begin sending at very low volumes like 1-200 emails per day. Yes, even if your email list has loads of people on it. You don’t want to just overload the systems and look scammy and salesy!

Gradually increase sending over weeks/months as engagement metrics remain healthy.

Keep an eye on complaint rates

Closely monitor complaint rates and spam folder placements. When people click “spam” on your email, well, I’m sure you can guess that is bad! Use double opt-in and confirmation messages to build valid lists. No buying your lists!

Segmentation for the win

Segment your list into smaller campaigns rather than large blasts. This helps you to send relevant content personalized for each subscriber which provides a better user experience too.

Don’t send the same thing all the time!

Switch things up to avoid the spam automation detectors. Mix email types like promotions, newsletters, onboarding flows. It’s also a good idea to pause/throttle sends if complaints or spam reports increase.

As things progress, adjust efforts based on continuous monitoring and analytics.

Following IP warmup guidelines demonstrates responsible sending and benefits long-term deliverability.

When should you warm up a new IP?

There are a few common scenarios when you should warm up a new IP address:

Getting a new dedicated IP

If you purchase a new dedicated IP address for sending email campaigns, it will have no reputation, so you need to properly warm it up.

Switching email service providers

When you switch ESPs and start sending from their IP addresses, you'll be sending from an unknown IP as far as inbox providers are concerned, necessitating a warmup period.

Adding more IPs

If your email volume has increased and you add additional IP addresses to send from, warmup the new IPs before using them at full sending capacity.

Reactivating a Dormant IP

If you haven't sent any emails from an IP for an extended period, its reputation may have declined or been forgotten. Warm it up again before full use.

Launching a New Brand/Domain

When launching a new brand, domain or campaign type, warmup the IP reputation for this new identity from scratch.

The key triggers are initiating sending from a "new" IP address that inbox providers have little or no behavioral data and engagement history for yet. Following IP warmup best practices helps establish positive metrics and sender reputation for unfamiliar IPs. This minimizes the risk of spam filters blocking your emails.

Common IP Warmup Challenges



We know you want to get your emails out to the masses, but there are a few challenges you should be aware of. For example, rushing the process can get you blocked fast! A few additional challenges include:

- Not carefully validating subscriber opt-ins

- Failing to monitor and respond to feedback signals

- Sending irrelevant or low-quality content

- Overly promotional messaging without value

- Sudden spikes in volume triggering alarms

Now for the good news. With patience, care, and diligent tracking, senders can avoid these missteps and successfully warm up IPs for optimal deliverability.

What Should You Do If You Have an Urgent Need to Email Your List?

We get it. There are times you will want to email your entire list to share a sale. Sometimes this is an urgent need if cash flow is tight and you’re trying to drum up business quickly. But, the problem is if you rush, you could get blacklisted. Then, you won’t be getting through to any of your current or prospective customers.

If you really need to email your whole list, at least avoid the urge to do it all at once. Use the best practices we mentioned of segmenting your list. For example, instead of emailing everyone, only email the people on your list that are the most likely to actually make a purchase at this time - i.e. hot leads.

Address any complaints you receive, and honor any unsubscribes immediately. Protect your list like the pile of gold it’s worth. Even with IP warmup, it’s always better to be safe than risk blacklisting!

The Power of Patience for Email Success

IP warmup may seem tedious, but dedicating the required time and care to this process pays off tremendously in long-term email deliverability, engagement, and returns from your campaigns.

Rushing the process only risks harming your sender reputation through sudden spikes in volume or promotional content from an unknown entity. Proper IP warmup demonstrates good sending practices and garners the engagement and trust needed to establish credibility with inbox providers.

Be patient, be strategic, and keep the lines of communication open through double opt-ins, relevancy and valuable content. Follow recommended IP warmup guidelines and schedules tailored to your specific needs. Monitor key metrics closely to catch any issues early. With diligence, your IPs will be primed for email success.

While in a rush to drive results, it's easy to skip over IP warmup as an unnecessary hurdle. But this deliberate process acts as the foundation for all your future email achievements by ensuring reliable inbox delivery. Respect IP warmup, build good habits early, and reap the rewards for the long-term. Your subscribers and inbox providers will thank you.

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