Summary
Warming up an email list after a welcome series requires a gradual increase in sending volume to establish a positive sender reputation with ISPs, avoiding being flagged as spam. This involves targeting engaged subscribers first, segmenting your list, and sending valuable, personalized content. A typical warm-up schedule lasts 4-8 weeks, but monitoring your sending reputation and deliverability metrics is crucial. Technical aspects such as proper authentication (SPF, DKIM, DMARC) and adhering to daily sending limits are essential. Also, acknowledge the period of inactivity since the welcome series and explain it to your subscribers.
Key findings
- Gradual Volume Increase: Ramp up sending volume slowly to avoid triggering spam filters.
- Engaged Audience First: Prioritize sending to subscribers who actively engage with your emails (opens, clicks, game activity).
- Segmentation is Key: Segmenting your list allows you to target engaged users, which improves deliverability.
- Personalization Matters: Deliver valuable, personalized content relevant to subscriber interests to encourage engagement.
- Monitoring is Essential: Constantly monitor sending reputation and deliverability metrics (bounces, complaints) to adjust strategy.
Key considerations
- Infrastructure Awareness: Understand your sending infrastructure (ESP, shared IP, etc.).
- Machine Learning Filters: Be aware that machine learning filters dislike drastic changes in sending patterns.
- Acknowledge the Absence: Consider explaining the lack of recent emails to subscribers to avoid confusion.
- List Hygiene: Clean your list by removing inactive subscribers to improve engagement rates.
- Authentication: Implement and maintain SPF, DKIM, and DMARC authentication protocols to prove legitimacy.
- Sending Limits: Set and adhere to daily sending limits to avoid being flagged as a spammer.
What email marketers say
12 marketer opinions
Warming up an email list after only sending a welcome series involves gradually increasing the sending volume to maintain a good sender reputation with ISPs. This is achieved by sending to smaller segments of the most engaged users first and gradually increasing the volume, usually over 4-8 weeks. Personalized and valuable content is key to driving engagement. Cleaning the list and proper authentication protocols are also important.
Key opinions
- Gradual Volume Increase: Slowly increase sending volume to establish a positive sending reputation.
- Engaged Subscribers First: Start with highly engaged subscribers (opened/clicked in the last 30-90 days).
- Segmentation Importance: Segment your list to focus on the most active users first.
- Personalized Content: Provide valuable, personalized content tailored to subscribers' interests.
- Warm-up Timeline: A typical warm-up schedule lasts 4-8 weeks.
Key considerations
- List Cleaning: Clean your list by removing inactive or unengaged subscribers.
- Content Relevance: Avoid generic content, focusing on value and relevance.
- Daily Sending Limits: Establish and monitor daily sending limits to avoid being flagged as spam.
- Authentication: Implement email authentication protocols (SPF, DKIM, DMARC) from the start.
- Explanation of Absence: Consider explaining the period of inactivity since the welcome series to subscribers.
Marketer view
Email marketer from Klaviyo shares you should segment your most engaged subscribers, those that have opened or clicked an email in the past 30-90 days and send to them first.
30 Mar 2023 - Klaviyo
Marketer view
Email marketer from Customer.io explains that a warm-up schedule typically lasts 4-8 weeks, gradually scaling from a few hundred emails per day to your standard sending volume.
28 Jun 2025 - Customer.io
What the experts say
4 expert opinions
When warming up an email list after a welcome series, a slow and steady approach is crucial. This involves gradually increasing the sending volume while monitoring IP reputation to avoid blacklisting. Prioritize sending transactional and subscription-prompted mail, starting with the most recently engaged users and working backwards. Ensure proper authentication with SPF, DKIM, and DMARC from the beginning. Be mindful of machine learning filters that flag sudden changes in sending volume and patterns.
Key opinions
- Machine Learning: Machine learning filters are sensitive to sudden changes in sending volume.
- Slow & Steady Ramp-Up: Gradually increase sending volume over time.
- Engaged Users First: Start with the most recently engaged subscribers.
- Transactional/Subscription Mail: Prioritize transactional and subscription-prompted emails during warm-up.
Key considerations
- IP Reputation: Monitor your IP address's reputation and avoid blacklists.
- Infrastructure: Understand your sending infrastructure (ESP, shared IP, etc.).
- Authentication: Implement and maintain SPF, DKIM, and DMARC authentication.
- Volume Awareness: Be aware of your normal daily/weekly send volumes and how the warm-up impacts them.
Expert view
Expert from Spam Resource answers that you should begin warming your new IP address with transactional and subscription/prompted mail. Also make sure to authenticate from the start with SPF, DKIM, and DMARC.
27 Oct 2023 - Spam Resource
Expert view
Expert from Word to the Wise explains the importance of a slow and steady approach to IP warm up. This means starting with a small volume of emails and gradually increasing it over time. It is also important to monitor the reputation of your IP address to ensure that it is not being blacklisted.
4 Jun 2022 - Word to the Wise
What the documentation says
4 technical articles
Warming up an email list, particularly after a prolonged period of inactivity, requires a gradual increase in sending volume to establish a positive sender reputation with ISPs. Start by sending to small segments of your most engaged users to demonstrate trustworthiness. Monitor deliverability metrics closely, including bounces and complaints, and adjust sending schedules accordingly. Maintaining good email content and engagement is crucial.
Key findings
- Gradual Ramp-Up: Gradually increase sending volume over time to build a positive reputation.
- Engaged Users First: Begin by sending to your most engaged users to demonstrate trustworthiness.
- Reputation Building: IP warm-up helps establish a positive sending reputation with ISPs.
Key considerations
- Deliverability Metrics: Monitor bounces, complaints, and other deliverability metrics.
- Sending Schedule: Adjust your sending schedule based on deliverability data.
- Content and Engagement: Focus on good email content and engagement to signal trustworthiness to ISPs.
- Daily Limits: Avoid exceeding daily sending limits to maintain a good reputation.
- Pause on Issues: Pause sending if you observe spikes in bounces or complaints.
Technical article
Documentation from MessageBird (formerly SparkPost) answers starting slow and ramping up gradually is the best way to build a sending reputation. Begin with your most engaged users. Keep a close eye on your deliverability metrics, and pause your sends immediately if you see a spike in bounces or complaints.
9 Jun 2022 - MessageBird
Technical article
Documentation from Twilio SendGrid answers IP warm up involves gradually increasing your sending volume over a period of time to establish a positive sending reputation with ISPs. Start by sending to small segments of your most engaged users, and gradually increase the number of recipients and frequency of sends.
18 May 2023 - Twilio SendGrid
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