Can I skip a day during email warm up without hurting my IP reputation?
Michael Ko
Co-founder & CEO, Suped
Published 13 May 2025
Updated 17 Aug 2025
6 min read
Email warming is a critical process for establishing a positive sending reputation for new or re-activated IP addresses and domains. It involves gradually increasing your email sending volume over a period, allowing mailbox providers to recognize your sending patterns and trust your emails. This slow, steady ramp-up helps ensure your messages land in the inbox, not the spam folder.
However, sometimes unforeseen circumstances, such as needing to clean a mailing list due to excessive bounces or misspellings, can lead you to consider pausing your warm-up schedule. The question often arises: can you skip a day or two during this crucial phase without negatively impacting your IP reputation (or your domain's reputation)?
Understanding how IP and domain reputation works is key to answering this. While consistency is generally recommended, a brief pause, especially for the right reasons, might not be as detrimental as you fear. We will explore the nuances of temporary pauses during email warm-up and what it means for your sender reputation.
The foundation of IP reputation
IP and domain reputation are built over time through consistent, positive sending behavior. Mailbox providers, such as Twilio SendGrid, assess your sending patterns, complaint rates, bounce rates, and engagement metrics to assign a sender score. A new IP address starts with a neutral reputation and must gradually earn trust. This is why email warm-up is essential.
The reputation you build is not instantaneous; it's based on a rolling window of recent sending history, typically 30 days. This means that a single day's activity, or lack thereof, is unlikely to entirely undo weeks of consistent effort. Mailbox providers use sophisticated algorithms that look at trends rather than isolated incidents.
Understanding this rolling window is crucial. If you've been warming up successfully for a week or two, a one or two-day pause will likely have minimal impact on the overall reputation trajectory. The accumulated positive sending data will outweigh the short break.
Key factors for good reputation
Consistent Volume: Gradually increase your sending volume, avoiding sudden spikes. This indicates legitimate sending behavior.
Low Complaint Rates: Aim for minimal spam complaints. High complaint rates are a major red flag for mailbox providers, and can lead to being placed on an email blacklist or blocklist.
Low Bounce Rates: Keep hard bounces to a minimum by regularly cleaning your list. This is often an indicator of list quality.
High Engagement: Positive interactions like opens, clicks, and replies signal to ISPs that your emails are valued.
When a temporary pause is acceptable
Yes, you can generally skip a day or two during an email warm-up process without severe penalty to your IP reputation. This is especially true if the pause is for a strategic reason, such as improving your list quality. In fact, sending to a problematic list will likely cause more damage than taking a short break.
Mailbox providers' filtering systems are designed to identify long-term patterns, not react drastically to minor, short-term fluctuations. A brief hiatus to rectify an issue like high bounce rates caused by internal test emails or typos can actually be beneficial. It allows you to address the underlying problem before it escalates and significantly harms your sender score. We have a detailed guide on whether IP warming requires consecutive days of sending, which provides further insight into this.
However, this flexibility has limits. Prolonged inactivity (more than a few days, especially over a week) can lead to an "IP cool-down" or even a reset of your reputation. Most reputation systems only store data for about 30 days, so if you go too long without sending, your prior warm-up efforts may diminish. For long-term pauses, you might need to re-warm up your email sending after a break.
Short term pause (1-2 days)
Reputation Impact: Minimal, especially if overall sending trends are positive. Reputation is based on a rolling average.
When to Use: Ideal for urgent list cleaning, resolving technical issues, or addressing unexpected bounce spikes.
Resumption: You can typically resume at your last successful sending volume without starting over.
Long term pause (weeks/months)
Reputation Impact: Significant decline, potentially leading to a loss of established reputation. Mailbox providers might view you as a new sender again.
When to Use: Only when absolutely necessary, acknowledging that a full re-warm will be required.
Resumption: Requires starting the warm-up process from a very low volume again, similar to a new IP. Read more about re-warming a dormant domain.
Mitigating risks during a pause
If you decide to pause your warm-up, it's crucial to use that time effectively to resolve any issues. For instance, if you're experiencing high bounce rates due to invalid addresses, use the pause to rigorously clean your list.
This involves identifying and removing any problematic email addresses, such as those with typos (e.g., gmail.con) or known test accounts. Filtering out these addresses before your next send can prevent further damage to your reputation and improve your overall deliverability rates. Remember, a high bounce rate can trigger blocklists (or blacklists) and spam filter scrutiny, leading to emails being sent to spam.
While you're paused, consider segmenting your list by engagement if you have historical data. Starting your next sends with highly engaged subscribers can provide positive signals to mailbox providers, reinforcing your reputation. For more strategies on how to manage your sending volume, see our guide on managing inconsistent bulk email sending volume.
Example: Cleaning a list
When cleaning your email list, prioritize removing addresses that are likely to hard bounce or be spam traps. This typically includes addresses with common misspellings or temporary domains. A simple regex can often identify many of these.
The regex above targets common typos like '.con' or '.coom' and also any email address containing 'test'. Adjust this regex to fit specific patterns of invalid addresses you observe in your bounce data.
Maintaining momentum post-pause
After a short pause, the general rule is to pick up where you left off. If your last successful send was at 10,000 emails, you can typically resume sending at or near that volume. Avoid drastically cutting your volume by more than half, as this can sometimes trigger an IP cool-down or slow down your warm-up process. It’s about maintaining a consistent, albeit gradually increasing, presence.
Continue to monitor your deliverability metrics closely, especially bounce rates and spam complaints. Tools like Mailgun advise that a good warm-up period ensures both your IP and domain build reputations with mailbox providers. This increases your chances of deliverability.
If you observe any negative shifts, such as increased bounces or a spike in spam complaints, it may indicate that the pause was longer than ideal, or the underlying issues weren't fully resolved. In such cases, you might need to slightly reduce your sending volume and gradually increase it again, following a revised IP warm-up strategy.
Can significantly erode established trust. May require a full re-warm-up, as if it were a new IP.
Deliverability
Unlikely to see major drops upon resumption, especially if the pause was used to clean lists.
High risk of emails landing in spam or being blocked when sending resumes. Inbox placement will suffer.
Warm-up Schedule
Generally, you can resume at the previous volume and continue the schedule. Don't drop volume by more than half.
A complete re-evaluation and often a reset of the warm-up schedule from a very low volume will be necessary.
In summary
Maintaining consistent sending behavior is ideal for email warm-up, but flexibility is also important. If you need to skip a day or two to address critical list hygiene issues, it's generally safe to do so. The short pause for cleaning your list is often less harmful than continuing to send to bad addresses, which can lead to higher bounce rates and spam complaints. These negative signals are far more detrimental to your IP and domain reputation than a brief break.
Always aim for quality over sheer volume, especially during warm-up. By taking a strategic pause to clean your list and prepare for better sending, you're investing in the long-term health of your sender reputation and email deliverability.
Views from the trenches
Best practices
Maintain a consistent daily or near-daily sending volume to build stable reputation.
Segment your audience and prioritize sending to engaged subscribers during warm-up.
Regularly monitor your email deliverability metrics like bounce and complaint rates.
Common pitfalls
Drastically changing sending volumes or skipping many days without good reason.
Sending to unengaged or outdated lists, leading to high bounce and complaint rates.
Ignoring feedback loops or DMARC reports that indicate deliverability issues.
Expert tips
If you must pause, use the time to enhance your list quality and prepare for resumption.
When resuming, aim to pick up at your last successful sending volume.
Reputation systems track trends, so a short, justified pause won't derail your efforts.
Marketer view
Marketer from Email Geeks says that they were in the middle of warming and saw many hard bounces due to internal test emails and misspellings. They needed legal approval for list cleaning, which would take 1-2 days, and wondered if skipping sending for those days would hurt their reputation.
2024-03-04 - Email Geeks
Expert view
Expert from Email Geeks says that you can certainly skip a day or two during a warming process without penalty.
