What strategies should I consider when warming up a new IP address for batch email sending?
Matthew Whittaker
Co-founder & CTO, Suped
Published 23 Jul 2025
Updated 18 Aug 2025
7 min read
When approaching a new IP address for batch email sending, the process of IP warming is fundamental to establishing a strong sender reputation and ensuring your emails reach the inbox. It's essentially about building trust with internet service providers (ISPs) like Google and Yahoo. Starting with a new or cold IP address requires a strategic approach to gradually increase sending volume without triggering spam filters or landing on an email blocklist (or blacklist).
My experience has shown that a failed warming attempt can set you back significantly. Factors like poor content selection, using image-heavy emails, or targeting unengaged audiences can quickly damage your domain and IP reputation. This guide will help you understand the core strategies for successfully warming up a new IP, particularly for recurring batch sends, and avoid common pitfalls to ensure your emails consistently reach your subscribers' inboxes.
Understanding IP reputation and warm-up basics
When you start sending from a new IP address, ISPs have no prior sending history for it. They are inherently cautious to prevent spammers from immediately sending large volumes of unsolicited mail. Your IP address, and by extension your domain, needs to earn its trustworthiness by demonstrating consistent, good sending behavior over time. This is why IP warming is a critical first step. It involves gradually increasing your email volume, starting with highly engaged recipients, and closely monitoring your deliverability.
A new IP address begins with a neutral reputation. Sending too many emails too quickly will signal suspicious activity to ISPs, leading to your emails being filtered into spam folders or outright rejected. This can also result in your IP being placed on a blocklist or blacklist, severely impacting your future email campaigns. The goal is to build a positive reputation by showcasing high engagement rates, low bounce rates, and minimal spam complaints during the initial warm-up phase.
This reputational foundation is based on various factors, including the consistency of your sending volume, the quality of your recipient list, and your authentication practices. It's not just about getting emails delivered, but about consistently reaching the inbox and being perceived as a legitimate sender by major mailbox providers. Proper setup of authentication protocols like SPF, DKIM, and DMARC is crucial from the outset to establish this legitimacy.
Crafting your batch sending warm-up schedule
For batch email sending on specific days like Mondays, Wednesdays, and Fridays, your warm-up schedule needs to account for these gaps. While daily sending is often recommended for faster warming, a consistent schedule, even with gaps, can still be effective if managed carefully. The key is to start with your most engaged subscribers, as their positive interactions (opens, clicks, replies) will send strong positive signals to ISPs. Gradually expand to broader segments of your engaged audience as your IP's reputation strengthens.
A common strategy for IP warming is to increase volume incrementally, typically by no more than 10-40% per send. If you're only sending three days a week, this means each send needs to be impactful and carefully monitored. Consider staggering your audience segments so that you can maintain a somewhat consistent daily volume, even if individual users only receive emails a few times a week. This allows the IP to receive continuous positive signals.
The duration of the warm-up can vary, but generally ranges from a few weeks to a couple of months, depending on your target volume and the initial reputation of your IP. Patience is crucial. Rushing the process will likely lead to deliverability issues. For detailed insights on building your reputation, refer to Rejoiner's guide on warming up an IP address.
Here's a sample daily/weekly warming schedule adapted for batch sending:
Day/Week
Target Volume
Audience Focus
Key Actions
Week 1
500-2,000 emails/day on send days
Highly engaged, active customers
Send on M/W/F. Monitor deliverability closely.
Week 2
2,000-5,000 emails/day on send days
Recently engaged customers
Maintain consistency. Expand audience carefully.
Week 3-4
5,000-15,000+ emails/day on send days
All active customers, beginning to mix in leads
Increase volume by 10-20%. Monitor engagement.
Post warm-up
Target batch volume
Full list, including riskier segments
Maintain consistent volume & good sender practices.
Content, audience, and technical readiness
Beyond just volume, the content and audience you choose are paramount during the warm-up phase. You want to send emails that recipients are likely to open, click, and engage with, not mark as spam. This builds a positive reputation for your dedicated IP and domain. High engagement signals legitimacy, while low engagement, bounces, or spam complaints indicate potential issues.
Audience selection
Start with: Your most active and engaged customers, especially those who consistently open and click your emails. These are your best advocates for a good sending reputation.
Segment gradually: Slowly introduce less active segments, leads, or re-engagement lists only after your initial sends are performing well.
Content quality: text vs. image-heavy
During warm-up, focus on emails with a higher proportion of live text compared to images. Image-heavy emails can sometimes be flagged by spam filters, especially if they lack sufficient text content. Ensure your messages are clear, concise, and provide immediate value to the recipient. Always include a clear and functional unsubscribe link.
Before you even start sending, ensure your technical setup is flawless. This includes setting up SPF, DKIM, and DMARC. These authentication protocols verify that your emails are legitimate and prevent spoofing, which is crucial for building trust with ISPs. Also, confirm that you have valid reverse DNS (PTR records) for your sending IP addresses that correctly point to your domain, as recommended by Google's email sender guidelines. If these are not correctly configured, your emails are much more likely to be sent to spam or rejected outright, hindering your warm-up efforts.
Warming up an IP isn't a set-it-and-forget-it process. Continuous monitoring of your email deliverability metrics is essential. Pay close attention to bounce rates, complaint rates, and open/click rates. Tools like blocklist monitoring and DMARC reports provide valuable insights into how ISPs are treating your mail. If you see an increase in bounces or complaints, it's a clear signal to slow down your sending volume and reassess your strategy before proceeding.
Reviewing your sending logs for deferred or bounced messages can offer early warnings about potential issues. Sometimes, emails might struggle to get delivered, but eventually go through. This is an indicator that your IP (or domain) might be experiencing some resistance, and it's not the right time to increase your volume. Being proactive in identifying and addressing these signals will prevent major deliverability setbacks.
Common pitfalls to avoid
Sending to unengaged lists: This is one of the quickest ways to damage your reputation and land on a blacklist or blocklist. Always prioritize engaged audiences first.
Abrupt volume spikes: Avoid sudden, large increases in sending volume, even after the initial warm-up. Gradual scaling is always best.
Ignoring metrics: Failure to monitor bounce rates, spam complaints, and overall engagement can lead to a prolonged or failed warm-up.
Inconsistent sending: While batch sending implies gaps, maintaining a predictable schedule, and possibly staggering audiences to fill non-batch days, helps build trust.
Remember, the success of your IP warm-up hinges on the quality of your list and the relevance of your content. Ensure your list is clean and consists of recipients who genuinely expect and want your emails. This will lead to higher engagement and a faster path to inbox placement, even with a specific batch sending cadence.
Views from the trenches
Best practices
Actively monitor your sending logs, bounce messages, and attempt statistics for early indicators of delivery issues.
Prioritize sending to highly engaged subscribers from the start to establish a positive sender reputation quickly.
Ensure consistency in your email content, aiming for a good balance of live text over purely image-based designs.
Implement and verify SPF, DKIM, and DMARC records before initiating any warm-up sends to ensure proper authentication.
Be prepared to adjust your sending volume downwards if you observe any signs of deliverability issues, like increased complaints.
Common pitfalls
Ignoring early warning signs in your logs, such as high bounce rates or deferred emails, can lead to larger problems.
Attempting to rush the warm-up process by increasing volume too quickly, which can trigger spam filters.
Sending to a generalized pool of recent openers instead of the most active customers, leading to lower engagement.
Neglecting proper email authentication (SPF, DKIM, DMARC) before starting the warm-up can severely hinder trust.
Failing to clean your email list and sending to inactive or invalid addresses, which contributes to poor sender scores.
Expert tips
If your IP and domain are relatively new or have had a previous unsuccessful warm-up, plan for a more conservative ramp-up.
For batch sending on specific days, consider if staggering audiences daily is feasible to provide continuous positive signals to ISPs.
Focus on the quality and relevance of your email content, ensuring it's what your audience expects and values.
A transactional or highly anticipated message type can be an excellent choice for initial warm-up sends due to expected high engagement.
Always ensure users can easily opt out of marketing messages, as this helps manage complaint rates and maintain list hygiene.
Marketer view
Marketer from Email Geeks says: You should carefully review your routing logs, bounce messages, and the number of attempts before considering any volume increases. If emails are struggling to get through, even if they eventually deliver, it indicates that it might not be the right time to increase your sending volume.
2024-01-16 - Email Geeks
Expert view
Expert from Email Geeks says: If both the IP and domain are relatively new, and there was a previous unsuccessful warm-up attempt, it's essential to understand the root cause of that failure and address it for this new attempt.
2024-01-16 - Email Geeks
Summary of key strategies
Successfully warming up a new IP address for batch email sending requires a methodical, data-driven approach. It’s a marathon, not a sprint. By focusing on a highly engaged audience, maintaining consistent, gradual volume increases, ensuring technical readiness, and diligently monitoring your performance, you can build the strong sender reputation necessary for optimal deliverability.
Even with a three-day-a-week sending cadence, consistency and careful audience management will pave the way for successful inbox placement. Remember that every email sent is an opportunity to reinforce your reputation, so make each one count by delivering valuable content to an engaged audience.
Google and 
Yahoo. Starting with a new or cold IP address requires a strategic approach to gradually increase sending volume without triggering spam filters or landing on an email blocklist (or blacklist).
