What is IP warming and how to do it in 2023

You’ve been there, right? You spend hours, maybe even days, crafting the perfect email. You hit ‘send’ and then… crickets. Your email ends up in the spam folder, never to be seen again. If this sounds familiar, you’re in the right place.

This comprehensive guide on IP Warming will teach you everything you need to know to improve your email deliverability, build a positive sender reputation, and help you drive more leads and ROI from your email campaigns.

We’ll walk you through the step-by-step process of warming up your IP address. You can combine the learnings from this guide with an IP warm up service like Inboxy to make improving your open rates 10 times easier and more seamless.

Illustration of a digital thermometer measuring the gradual increase in email volume linked to an IP address, symbolizing the IP warming process.

What is IP warming?

Imagine you are moving into a new town and you want to make friends. You don’t just go around talking to everyone all at once, right?

No, you start small. Maybe you chat with your neighbor first, and then maybe join a local organization or two. Slowly but surely, people start to recognize you. They get to know you, and you become a familiar face. That’s what IP warming is all about, but for your emails.

IP warming (or IP warm up) is a calculated strategy that involves gradually increasing the volume of emails sent through a specific IP address based on a pre-set schedule. You can’t just blast emails out to everyone. Why? Because Internet Service Providers (ISPs) like Gmail and Yahoo don’t know you yet. You’ve got to earn their trust.

When you initiate the IP warming process, you start off small by just sending a limited number of emails. This helps you gain credibility with email providers like Gmail or Outlook that you’re not a spammer but a legitimate email sender.

Over a span of several weeks or even months, you incrementally increase the volume of emails sent so that ISPs can gauge your sending behavior and assess whether your emails are likely to be welcomed by their users.

Why is IP warming important?

If your emails end up in the spam folder, you’re basically shouting into the void. No one hears you. So, warming up your IP address is like tuning your guitar before a concert. It ensures that when you strum those strings, the sound is music to the ears, not noise.

ISPs have sophisticated algorithms in place to assess the legitimacy of emails. When you’re NOT flagged as spam, your deliverability rates improve, ensuring that your emails actually reach the inbox of your recipients. This is crucial for the success of your email marketing campaigns and maximizing your ROI in the long-term.

During the IP warming process, it’s important to keep an eye on your open rates, click-through rates, and spam complaint rates. To familiarize ISPs with email sent from your new IP address, you should aim to accumulate about 30 days’ worth of sending history and statistics.

For certain senders, the warming process may take more than 30 days, while it could take less time for other senders. IP warm up depends on a number of variables, including subscriber engagement, list quality, and list size overall.

You can eliminate the guesswork and use a free inbox placement test to know exactly where your emails land in the inbox and whether they go in spam or not.

Why you need to warm up your IP address

  • Email Deliverability: If you don’t warm up your IP, ISPs are more likely to mark your emails as spam, reducing your deliverability rates. Proper IP warm up ensures that your emails reach the inbox. 
  • ISP Trust: ISPs are cautious about new or reset IP addresses. They are more likely to trust a warmed-up IP, ensuring your emails are delivered effectively.
  • Domain Reputation: A well-warmed IP not only builds trust with ISPs but also positively impacts your domain reputation, which is crucial for long-term email marketing success. Check and Improve Your Domain Reputation.

How to warm up an IP address?

Warming up an IP address involves sending a low volume of high-quality emails initially and gradually increasing the volume while monitoring key metrics like deliverability, open rates, and spam reports. This lets you build initial trust with ISPs so that they can welcome the rest of your emails. 

1) Gradual Increase in Email Volume: First, you start small. Send a few high-quality emails and see how they perform. Are people opening them? Good. Are they clicking on the links? Even better. Then, you gradually increase the volume. IP warm up is like learning to swim. You don’t dive into the deep end right away; you start in the shallow end and work your way deeper.

2) Monitoring and Adjustments: You can’t just set your IP warming strategy on autopilot and expect smooth sailing. You’ve got to monitor metrics like open rates, click-through rates, and spam reports to adjust your strategy. This is crucial for optimizing the IP warm up process. If your open rates are soaring, you’re on the right track. But if spam reports start trickling in, it’s a red flag, signaling it’s time to reassess and recalibrate your approach.

3) Timeframe for IP Warming: Typically, the IP warm up process takes between 15 to 60 days. This timeframe can vary depending on your email volume and how ISPs and recipients respond to your emails.

Graphic of a glowing IP address with ascending arrows, representing the progressive process of IP address warming.

Factors affecting IP reputation

  • Spam Reports: Every time someone marks your email as spam, it’s like a strike against you in the eyes of ISPs. So, what’s the game plan? Deliver content that actually matters to the recipient. If your emails offer real value, the likelihood of them being tagged as spam drops significantly.
  • Bounce Rate: A high bounce rate is a red flag for ISPs. They see a high bounce rate and think, “Hmm, this list doesn’t look clean.”. And just like that, It indicates that your email list may not be clean or up-to-date which can negatively affect your IP reputation.
  • Engagement Rate: ISPs love high user engagement when determining your IP reputation. High engagement rates, such as email opens and clicks, are huge positive signals to ISPs.
  • Email Content Quality: ISPs aren’t just gatekeepers; they’re also critics. They’re evaluating the quality and relevance of your emails. Crafting high-quality, relevant emails are less likely to be marked as spam and more likely to improve your IP reputation.

IP warming best practices

Preparing for IP warming

Before you dive headlong into the world of IP warming, there are some boxes you’ve got to check off. Think of it as laying the groundwork for a house; you wouldn’t start building without a solid foundation, would you?

  • Dedicated vs Shared IP: Picture a dedicated IP address as your own personal lane on the email highway. You control the speed, the rules, and most importantly, your reputation. On the other hand, a shared IP is like carpooling with strangers. You’re all in it together, which means if one person messes up, everyone feels the impact. For businesses with large email volumes, a dedicated IP is often the better choice but there are often several considerations. 
  • Setting Up Email Authentication: Implementing email authentication protocols like SPF, DKIM, and DMARC can significantly improve your email deliverability. These protocols verify that the emails are genuinely from you, reducing the likelihood of them being marked as spam.
  • Cleaning Email Lists: Before you start the IP warming process, it’s crucial to clean your email lists. Remove inactive users, incorrect email addresses, and anyone who has opted out to improve your engagement rates and overall deliverability.
Digital gauge with rising indicators and an IP address at its core, showcasing the methodical progression of IP warming.

IP warmup schedule

The IP warmup schedule is a critical component of the overall process. It’s a timeline that outlines how many emails you should send out each day to gradually build your reputation.

  • Initial Days: Start with a low volume, perhaps 50 to 100 emails per day. Monitor the metrics closely to see how these emails perform in terms of deliverability and engagement.
  • Mid-Phase: After the initial period, you can begin to increase the email volume to hundreds or even thousands per day, based on your needs. Continue to keep a close eye on metrics and make any necessary adjustments.
  • Final Phase: At this point, you should be ready to send emails at full volume. However, ongoing monitoring of metrics is still crucial to ensure that your email reputation remains strong.
  • Example IP Warming Schedule:
    • Day 1: 50 emails
    • Day 2: 100 emails
    • Day 3: 200 emails
    • Day 15: Full volume

Types of emails to send

Your sender reputation may be impacted by the kind of emails you send during the IP warm-up phase.

  • Transactional Emails: These are emails that a user initiates, such as a password reset or account creation. They are an excellent option for the first stage and often have high open rates.
  • Marketing Emails: Marketing emails should only be sent to users who have opted in, and they should be introduced gradually. Ensure that the information is interesting and relevant.
  • High-Engagement Emails: Emails with a high open and click-through rate are referred to as high-engagement emails. Sending these kinds of emails may immediately improve your reputation.

Monitoring and adjustments

Monitoring isn’t just a one-off task; it’s a continuous requirement for a successful IP warming process. It’s akin to a health check-up for your email campaign, helping you identify what’s working and what needs improvement.

  • Open Rates: If you’re seeing low open rates, it’s time to take a closer look. This could be a sign that your emails are landing in the spam folder. The culprit could be your subject lines. Are they engaging? Are they relevant? If not, it’s time for a revamp.
  • Click-Through Rates: Low CTRs are another area of concern. They could indicate that your email content isn’t hitting the mark. This is where A/B testing can come in handy. Try different versions of your email to see which elements resonate most with your audience.
  • Unsubscribes and Complaints: A spike in unsubscribes or complaints is a red flag that you can’t afford to ignore. It’s a clear signal to review your content and targeting strategy. Are you sending relevant content? Is your targeting off? These are questions you’ll need to answer.
  • Tools for Monitoring: To keep track of all these metrics, you’ll need the right tools. IP warm up tools like Inboxy track your domain’s reputation metrics and compare against our database of domains to ensure you always acheive better email deliverability. Don’t also overlook the analytics provided by your own email service provider. These tools can give you a comprehensive view of your performance.

Common mistakes and how to avoid them

Even with the best intentions, mistakes can happen. Here are some common missteps in the IP warming process and how to avoid them:

  • Overloading the IP: It’s tempting to send out a large volume of emails quickly, especially if you’re eager to reach your audience. However, doing so can set off spam filters. The remedy? Stick to your IP warmup plan and schedule. It’s there for a reason.
  • Poor Email Content: Low-quality or irrelevant content can lead to low engagement rates and spam reports. Always aim for high-quality, relevant content. It’s better to send fewer, more impactful emails than to flood inboxes with content that doesn’t resonate.
  • Ignoring Feedback Loops: ISPs offer feedback loops that alert you when someone marks your email as spam. Ignoring this valuable information is a mistake. Use these insights to fine-tune your strategy and enhance your content.

The role of email authentication in warming your IP

Email authentication is not just a smart practice when it comes to IP warming; it is also required. ISPs use it as the basis for determining the reliability of your emails.

  • SPF, DKIM, and DMARC:
    • Using the SPF (Sender Policy Framework) protocol, you may determine which IP addresses are allowed to send emails on your domain’s behalf. It makes it easier for ISPs to recognize and filter out phishing emails rapidly.
    • ISPs can use the encrypted signature that DKIM (DomainKeys Identified Mail) applies to your emails to confirm that you sent them and that they weren’t changed in transit.
    • Combining the benefits of SPF and DKIM, DMARC (Domain-based Message Authentication, Reporting, and Conformance) adds an additional layer of security by laying out the procedures that ISPs must follow when emails fail any of the earlier tests.

Adopting these standards greatly lowers the possibility that your emails will be classified as spam. In the email IP warming phase, when building a solid sender reputation is the main objective, this is vital.

Flowchart diagram displaying sequential stages of the IP warming process, from initial email volume to increased trust with ISPs.

IP warming for high-volume senders

For organizations that send out large volumes of emails, the stakes are high, and the IP warming process becomes even more critical. So, what should you be especially mindful of?

Special Considerations:

  1. Segmenting Email Lists: One size doesn’t fit all, especially when you’re sending emails in large volumes. Segment your email lists based on engagement levels. Focus first on your most engaged subscribers—those who open, read, and click through your emails. This not only boosts your sender reputation but also ensures that your emails are hitting the mark with the people who matter most.
  2. Multiple Dedicated IPs: Think of your email types as different asset classes in an investment portfolio. Just as you wouldn’t put all your money in one stock, consider using multiple dedicated IPs for different types of emails. For example, transactional emails could go through one IP, while marketing emails use another. This diversification can protect your sender reputation; if one IP gets flagged, it won’t bring down your entire operation.
  3. Throttling: Sending a large volume of emails at once can be akin to opening the floodgates—it’s overwhelming and can trigger spam filters. Implement throttling to control the rate at which emails are sent. This is like pacing yourself in a marathon; you don’t want to sprint right out of the gate only to collapse before the finish line.

Best IP warm up service and tools

The market offers a plethora of tools and services designed to assist in the IP warming process. But how do you sift through the noise to find the top IP warm up service that’s genuinely useful?

  • Features to Look For:
    • Real-Time Analytics: In a world where everything is fast-paced, real-time analytics are everything. They allow you to monitor your campaign’s performance as it happens, not after the fact. This is crucial for making on-the-fly adjustments.
    • Feedback Loop Integration: Feedback loops are like your campaign’s smoke detectors, alerting you when something’s amiss. A tool that integrates these loops can be invaluable for nipping issues in the bud before they escalate.
    • Customizable warming schedules: Every email campaign is unique, so a one-size-fits-all approach won’t cut it. Look for tools that allow you to customize your IP warming schedule to fit your specific needs.

At Inboxy, we offer all of this with our IP warm up service that uses AI and headless browsers to improve your open rates and email responses in 14 days or less.

Legal Aspects and Compliance

Navigating the legal landscape is crucial when you’re warming up an IP.

  • CAN-SPAM Act: In the United States, the CAN-SPAM Act sets the rules for commercial email, establishes requirements for commercial messages, and gives recipients the right to stop emails. Violating these rules can result in hefty fines.
  • GDPR: In Europe, the General Data Protection Regulation (GDPR) requires explicit consent from users before you can send them emails. Non-compliance can result in severe penalties.


IP Warming is an essential practice for anyone looking to optimize their email marketing campaigns. It involves a gradual increase in email volume sent from a new or reset IP address to build a good sender reputation. This guide has covered everything from the basics to advanced topics, providing a comprehensive look at IP warming.

Key Takeaways

The success of your IP warming strategy hinges on a thorough warm-up plan, continuous monitoring, and timely adjustments. 

  • IP Warming is vital for successful email marketing, helping to improve deliverability rates.
  • The process involves a gradual increase in email volume sent from a new or reset IP address.
  • Monitoring metrics like open rates, click-through rates, and spam reports is essential for optimizing the process.
  • Special considerations for high-volume senders include segmenting email lists and possibly using multiple dedicated IPs.
  • Tools like Inboxy can assist in monitoring IP reputation and email metrics.

Frequently Asked Questions

In this final section, we’ll address some of the most frequently asked questions about IP Warming and building a positive sender reputation over time. These questions often arise during the planning and execution phases of an IP warming strategy.

1. What is IP Warming?

IP Warming is the process of gradually increasing the volume of emails sent from a new or reset IP address. This is done to establish a good sender reputation with Internet Service Providers (ISPs).

2. What is an example of IP warming?

An example of IP warming would be starting with sending 50 emails on the first day from a new IP address, then doubling that number each subsequent day while monitoring deliverability metrics.

3. How long does IP Warming take?

The duration of the IP warming process can vary depending on several factors, including your email volume and the quality of your email list. Generally, it takes between 15 to 60 days to effectively warm up an IP address.

4. Can I speed up the IP Warming process?

Speeding up the IP warming process is not recommended, as it can lead to your emails being marked as spam. However, if you have a highly engaged email list and are closely monitoring metrics, you may be able to expedite the process cautiously.

5. What happens if I don’t warm up my IP?

Failure to warm up your IP can result in poor email deliverability. ISPs may mark your emails as spam, which will negatively impact your sender reputation and reduce the effectiveness of your email marketing campaigns.

6. How do I know if my IP Warming is successful?

Success in IP warming is generally indicated by high deliverability rates, low bounce rates, and low spam complaint rates. Monitoring these metrics closely will give you a good indication of whether your IP warming process is successful.

7. What is IP warming for email marketing?

In email marketing, IP warming helps in building a good sender reputation, ensuring that your emails land in the recipient’s inbox rather than the spam folder.

8. Is IP warming the same as domain warming?

No, IP warming focuses on the IP address, while domain warming focuses on building the reputation of the domain from which emails are sent.

9. Process for warming up IP address for email?

Start by sending a small number of emails and gradually increase the volume while monitoring key metrics. Make adjustments as needed based on these metrics.

10. How long does it take to warm up an email address instantly?

Instant warming is not recommended. The process should be gradual, usually taking between 15 to 60 days for best results.

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Anirudh Kaushal

Anirudh Kaushal is the Founder and CEO of Alchemy Automations and the Chief Technology Officer at Leadbird. Additionally, he serves as the CTO of Vendisys and is a Co-founder and Partner at Scrubby and Golden Leads. An expert in automation and cyber security, Anirudh's extensive knowledge covers data validation, email strategies, email security, software development, and IT management. His leadership and innovative approaches significantly advance the technological and security standards within these companies, driving industry progression.