IP Warming Checklist for B2B Email Campaigns

Silvio Bonomi
Oct 6
12 min read

When you send emails from a new IP address, internet service providers (ISPs) don’t trust you right away. Without proper IP warming, your emails can land in spam folders or get blocked entirely. IP warming is the process of gradually increasing your email volume to build trust with ISPs, ensuring your messages reach inboxes.

Here’s the quick process:

Start Small: Send emails to your most engaged recipients first (50–200/day) and scale up weekly by 50–75%.
Monitor Metrics: Track open rates (aim for 20%+), bounce rates (<3%), and spam complaints (<0.1%).
Prepare Your Setup: Use a dedicated IP, authenticate your domain (SPF, DKIM, DMARC), and clean your email list.
Stay Consistent: Maintain a predictable sending schedule and avoid sudden volume spikes.
Fix Issues Fast: If bounce rates or complaints rise, reduce volume and troubleshoot immediately.

Skipping IP warming can damage your sender reputation, lead to blocklisting, and hurt your email deliverability long-term. Follow these steps to protect your campaigns and ensure your emails reach decision-makers’ inboxes.

A Comprehensive Guide to IP Warming

Setup Steps Before IP Warming

Before you dive into the gradual sending process, it’s crucial to lay down the groundwork. A solid setup ensures your email campaigns build a strong reputation with ISPs, avoiding pitfalls like blocklisting. Think of it as preparing the soil before planting - without it, your efforts might not yield the results you’re aiming for.

To get started, focus on three key areas: data hygiene, domain authentication, and technical setup. Each one plays a critical role in making sure ISPs see your email activity as legitimate from the very first message.

Clean Your Email Lists

The quality of your email list can make or break your IP warming efforts. Sending messages to invalid addresses, role-based emails, or inactive contacts leads to high bounce rates and spam complaints - exactly what you want to avoid during this critical phase.

Start by using an email verification service to weed out invalid addresses. Pay special attention to hard bounces, which occur when an email address doesn’t exist or the domain is inactive. These are red flags for ISPs and can hurt your sender reputation right out of the gate.

Next, segment your list to prioritize engaged contacts. Focus on recipients who have interacted with your emails - like opening messages, clicking links, or replying - within the past 90 days. These are your best bets for positive engagement, which is essential during the warming process.

Avoid sending to role-based addresses like sales@, support@, or admin@ during this phase. These types of addresses can lead to higher bounce rates or complaints, so save them for later once your IP is established.

For B2B campaigns, the source and age of your email contacts are especially important. Contacts you’ve met at events or those who’ve downloaded your content are far more reliable than purchased lists or scraped data. For example, when Artemis Leads manages campaigns, they prioritize prospects with some level of prior engagement, ensuring smoother deliverability during the warming process.

Set Up Domain Authentication

Domain authentication is your way of proving to ISPs that you’re authorized to send emails from your domain. Without it, even legitimate emails can be flagged as suspicious - or worse, blocked entirely.

To set this up, configure SPF, DKIM, and DMARC:

SPF (Sender Policy Framework): Defines which IP addresses are allowed to send emails on behalf of your domain.
DKIM (DomainKeys Identified Mail): Adds a digital signature to your emails, ensuring they haven’t been tampered with during transit.
DMARC (Domain-based Message Authentication, Reporting, and Conformance): Instructs receiving servers on how to handle emails that fail authentication checks.

During the IP warming phase, start with a monitoring policy () for DMARC. This allows you to gather data on how your emails are being handled without impacting delivery. Once your sending patterns are consistent, you can tighten the policy for added security.

Once authentication is in place, it’s time to fine-tune your technical setup.

Prepare Your Technical Setup

Your technical infrastructure needs to be rock-solid before you start warming your IP. This includes using a dedicated IP, setting rate limits, and enabling real-time tracking.

A dedicated IP address is critical for serious email campaigns. Unlike shared IPs, where your reputation is tied to other users’ behavior, a dedicated IP gives you full control over your sender reputation. It’s a must-have if you’re aiming for consistent, high-quality deliverability.

Set rate limits to control how many emails are sent each day. Gradual volume increases are key to IP warming, and platforms like Mailgun, SendGrid, or Amazon SES allow you to configure these limits. Make sure these settings are in place before you start sending.

Enable real-time tracking to monitor engagement and handle unsubscribe requests promptly. During IP warming, every interaction matters, so you’ll want to address any issues quickly to maintain a positive reputation.

Finally, test your email templates and content across different email clients. Broken formatting or missing images can hurt engagement rates, which is especially damaging during the warming period when every email interaction counts.

Step-by-Step IP Warming Process

Starting the IP warming process requires patience and precision. The goal is to gradually build your email sending volume while maintaining consistent engagement, mimicking natural email behavior. This careful approach helps safeguard your sender reputation. Artemis Leads follows a structured process to ensure success.

The warming phase typically lasts 2–8 weeks, depending on your target volume and the feedback you receive from ISPs. During this time, you'll slowly increase your daily email count while closely monitoring recipient and ISP reactions. These steps are designed to help you transition smoothly into the active warming phase.

Increase Email Volume Gradually

Begin with a small volume and scale up carefully. On the first day, send 50–100 emails to your most engaged contacts - those who have recently interacted with your brand or shown clear interest.

As you progress, increase your sending volume cautiously. For example:

Start with 50–200 emails per day in the first week.
Move to 300–500 daily emails in the second week.
By the third week, aim for 800–1,200 emails daily.

Continue to increase your volume incrementally, by about 50–75% each week, until you reach your target. If engagement metrics are strong - such as open rates above 25% and bounce rates under 2% - you may consider a faster ramp-up. However, if engagement drops or issues arise, slow down. Keep in mind that ISPs like Gmail and Outlook are more lenient, while Yahoo tends to be stricter.

Some senders opt for a slower micro-warming period, starting with just 25–50 emails daily for the first two weeks to establish trust before ramping up. Campaigns targeting large enterprises may require a longer warming period compared to those aimed at smaller businesses.

Maintain a Regular Sending Schedule

Consistency is key. ISPs favor predictable sending patterns, so establish a routine and stick to it. Irregular sending or sudden spikes in volume can trigger spam filters and slow your progress.

Set specific sending times and avoid sending emails on weekends or holidays, as business-related emails tend to perform better on weekdays. Spread your daily volume across 2–3 smaller batches instead of sending all emails at once. This approach creates a natural engagement pattern.

If you need to pause sending for any reason, don’t resume at full volume immediately. Instead, restart at about 70% of your previous level and gradually build back up over several days. This prevents ISPs from flagging sudden increases.

If targeting multiple regions, stagger your sends to match local business hours. This helps create a more natural flow of engagement and improves your chances of landing in recipients' primary inboxes.

Monitor Performance and Adjust

Daily performance tracking is essential during IP warming. Small issues can escalate quickly, so stay vigilant and address problems promptly.

Pay close attention to metrics like open rates, bounce rates, spam complaints, and unsubscribe rates. For B2B campaigns, aim for:

Open rates above 20%
Bounce rates below 3%
Spam complaints under 0.1%
Unsubscribe rates below 0.5%

If bounce rates exceed 5% or spam complaints hit 0.3%, reduce your sending volume by 50% and investigate the cause. These issues often point to problems with your email list, content, or targeting.

Also, consider how quickly recipients open your emails. High open rates within the first 2–4 hours suggest strong deliverability to primary inboxes. Delayed opens might indicate that your emails are landing in promotions or filtered folders.

Use tools like 250ok or Litmus to test inbox placement. These tools can help you see whether your emails are landing in the primary inbox, promotions tab, or spam folder, allowing you to adjust your strategy before issues escalate. Additionally, even a few genuine replies during the warming process can signal ISPs that your emails are valuable.

When problems arise, don’t just lower your volume - dig deeper. Check your email content for spam triggers, ensure your sending domains aren’t blacklisted, and verify that your authentication records are correctly configured. Often, a small technical tweak can resolve issues more effectively than simply reducing your sending volume. These adjustments set the stage for long-term deliverability success.

Monitor and Improve During IP Warming

Keeping a close eye on your email performance during the IP warming phase is crucial. This period is all about building your sender reputation, and real-time monitoring helps you catch and address issues before they escalate. As you gradually increase your email volume, staying vigilant ensures your deliverability remains on track.

The warming phase is also a chance to fine-tune your strategy. Internet Service Providers (ISPs) pay close attention to your sending habits, rewarding consistent and engaging behavior. This is your opportunity to show ISPs that you’re a reliable sender.

Metrics to Track

Regularly checking key metrics will help you spot trends and address concerns early. Here are the most important ones to monitor:

Deliverability: A sudden drop could signal issues with volume increases or other underlying problems.
Open rates and speed: If these decline, it may indicate inbox placement issues or that your content isn’t resonating with your audience.
Bounce rates: High hard bounce rates can damage your reputation and point to poor list quality.
Spam complaints: Even a slight uptick can trigger ISP warnings, so keep an eye on this.
Unsubscribe rates: A rise here suggests your content or targeting might need adjustment.
Reply rates: Positive responses not only provide valuable audience insights but also signal engagement to ISPs.

Use these insights to tweak and improve your email content and strategy, ensuring better engagement as you move forward.

Improve Content and Engagement

Engagement is key during this phase, so focus on creating emails that resonate. Start with personalized subject lines that grab attention and content that offers real value. Instead of generic sales pitches, share educational tips, industry updates, or tailored recommendations that build trust with your audience.

When testing your emails, keep it simple. A/B test one element at a time - like the tone of your subject line or the time of day you send. Once you find what works, apply those learnings to larger segments. Also, aim for concise emails with a clear call-to-action. Shorter, focused messages often perform better during this stage.

Don’t forget to experiment with send times. Finding when your audience is most likely to engage can make a big difference. Tools that score your content can also help you identify potential spam triggers, allowing you to address them before they harm your sender reputation.

Use ISP Feedback

ISPs provide valuable feedback that can help you safeguard your sender reputation. Use tools like Gmail’s Postmaster Tools, Microsoft’s Smart Network Data Services, and Yahoo’s feedback systems to stay informed. If you spot issues - like authentication warnings or rising complaints - act quickly to resolve them.

Make sure your domain and IP reputation stay healthy by regularly checking your authentication protocols (SPF, DKIM, and DMARC). These protocols are essential for building trust with ISPs. Set up automated alerts for critical metrics so you can respond to problems immediately. Additionally, routine blacklist monitoring helps ensure your IP and domain remain in good standing.

Best Practices After IP Warming

Completing IP warming is just the first step. Protecting the reputation you've built is essential for maintaining strong email deliverability. Without ongoing care, even a well-warmed IP can quickly lose its standing, impacting your campaigns and sending emails straight to spam.

After warming, the focus shifts from earning trust to keeping it. By sticking to consistent, reliable practices, you can safeguard your sender reputation and continue scaling your outreach without setbacks. Here’s how to keep your email campaigns on track.

Keep Lists Clean

Maintaining a clean email list is crucial after warming. Regularly cleaning your lists - ideally once a month - helps ensure you're only reaching engaged recipients. Remove contacts who haven’t interacted in the past six months, as this can significantly improve deliverability and reduce bounce rates by up to 80% in some cases.

Start by eliminating hard bounces immediately after each campaign. Invalid email addresses hurt your reputation, so use verification tools to catch mistakes like typos or invalid domains before they cause issues. Automating processes to flag contacts with declining engagement can save time and keep your lists fresh.

Segmenting your audience by engagement levels is another key habit. Separate your contacts into groups such as highly engaged (those who frequently open or click), moderately engaged (occasional openers), and inactive (no recent activity). You can even assign engagement scores - like +10 points for opens, +15 for clicks, and +25 for replies - to make data-driven decisions about where to focus your efforts. These steps will help maintain your deliverability long after warming.

Maintain Good Sender Reputation

Your warmed IP is an asset, but keeping it in good standing requires consistent effort. Stick to a regular sending schedule and avoid sudden spikes in volume, as these can raise red flags with ISPs. For instance, if you were sending 5,000 emails daily during warming, don’t jump to 20,000 emails overnight.

Monitor your email performance closely. Pay attention to metrics like open rates, click-through rates, bounce rates, spam complaints, and unsubscribes. Set up alerts for sudden changes - a drop in open rates might signal inbox placement issues, while a rise in spam complaints could point to problems with your content or list quality.

To keep engagement high, refresh your email content regularly. Experiment with different subject lines, send times, and formats. Positive signals like replies and forwards show ISPs that your emails are valuable to recipients, further boosting your reputation.

Scale Outreach Smartly

Once your IP is warmed and stable, you can begin scaling your outreach - but do it carefully. Gradually increase your sending volume while keeping a close eye on engagement and deliverability metrics. If performance starts to dip, pause the increase and investigate the cause before moving forward.

Consider combining email campaigns with LinkedIn outreach to cover your entire Ideal Customer Profile. This multi-channel strategy ensures you connect with decision-makers across their preferred platforms. For example, Artemis Leads aligns email and LinkedIn outreach to effectively target prospects. While email works well for those who prefer formal communication, LinkedIn is ideal for engaging users active on social platforms. Together, these channels create a stronger lead generation system.

Finally, avoid overwhelming your IP by sending more than 2 million emails daily from a single address. Track your results across all channels, refining your multi-channel sequences to improve overall campaign performance. This balanced approach will help you scale while preserving the reputation you worked hard to build.

Conclusion

After laying a solid foundation and following a structured warming process, there are a few key steps to ensure your email deliverability remains strong. IP warming plays a crucial role in the success of B2B email campaigns, requiring a steady, disciplined approach to improve deliverability and achieve better results.

Increase your email volume gradually over a period of 4–8 weeks. Start by targeting your most engaged subscribers, then scale up by 50–100% each week to build trust with Internet Service Providers (ISPs). Keep a close eye on important metrics like bounce rates, open rates, click-through rates, and spam complaints. These indicators will help you catch and resolve any issues early, protecting your sender reputation. Remember, mailbox providers rely heavily on your reputation when deciding whether your emails land in inboxes or spam folders.

Focus on maintaining clean email lists and a strong sender reputation while scaling your outreach efforts thoughtfully. To amplify your impact, combine email outreach with LinkedIn messaging, as demonstrated by Artemis Leads. This multi-channel approach ensures you connect with every segment of your ideal customer profile.

Ultimately, success with IP warming boils down to sticking to the basics: prepare thoroughly, scale your efforts gradually, monitor metrics consistently, and maintain your reputation diligently. Treat your IP reputation as a critical business asset, and by following these steps, your B2B email campaigns will reliably reach decision-makers and deliver meaningful results.

FAQs

What is IP warming, and why is it important for B2B email campaigns?

IP warming involves gradually increasing the number of emails sent from a new IP address. The goal? To build trust with Internet Service Providers (ISPs). This process is essential for B2B email campaigns because it helps ensure your emails land in recipients' inboxes instead of being flagged as spam.

By taking the time to warm up your IP, you reduce the chances of poor deliverability - like emails being blocked or sent to junk folders. Slowly ramping up your email volume shows ISPs that your sending activity is legitimate, which protects your sender reputation and boosts the overall success of your campaigns.

How can I maintain a strong sender reputation after completing the IP warming process?

To keep your sender reputation in good standing after IP warming, it's crucial to maintain a steady flow of well-crafted emails aimed at recipients who are genuinely interested. Avoid abrupt increases in the number of emails you send, and make it a habit to validate your email list frequently to weed out invalid or inactive addresses.

Keep an eye on essential metrics like bounce rates, open rates, and overall engagement to gauge how well your campaigns are doing. Also, make list hygiene a priority - update your database regularly and focus on reaching the right audience. Staying consistent and vigilant will help you protect and sustain a strong sender reputation over the long haul.

What’s the best way to monitor and resolve email deliverability issues during IP warming?

To ensure your emails reach their destination during the IP warming process, keep a close eye on key metrics like deliverability rate, bounce rate, and engagement levels. Regularly reviewing these numbers allows you to spot and address issues early, such as a sudden drop in engagement or an unusual increase in bounces.

By gradually increasing your sending volume and sticking to a consistent schedule, you build trust with inbox providers over time. If you encounter any hiccups, consider adjusting your sending volume or fine-tuning your email content to boost performance. Staying vigilant and responsive during this phase lays the groundwork for long-term email success.