How to warm up an email list after only sending a welcome series?

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
12Marketer 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.

June 2022 - 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.

October 2022 - Customer.io
Marketer view

Email marketer from Mailjet explains warming up an email list involves sending emails in small batches, gradually increasing the volume over time. This demonstrates to ISPs that you're a legitimate sender and helps improve your sender reputation.

April 2021 - Mailjet
Marketer view

Email marketer from EmailToolTester shares it's better to start with smaller numbers of emails (500-1,000) and increase your volumes slowly. Also set a daily sending limit and use authentication protocols.

July 2024 - EmailToolTester
Marketer view

Email marketer from Email Geeks shares that you should start with the most engaged customers on a subset to see how it goes. Send the announcement over a few days. Include a message explaining the lack of emails since sign-up.

January 2022 - Email Geeks
Marketer view

Email marketer from ActiveCampaign shares the key element is to send emails gradually and consistently. Send to your most engaged audience first.

March 2024 - ActiveCampaign
Marketer view

Email marketer from Warrior Forum explains to focus on delivering value to subscribers and avoid sending generic or irrelevant content. Personalize your messages and tailor them to the individual interests of each subscriber.

February 2024 - Warrior Forum
Marketer view

Email marketer from Zoho recommends that email warm-up refers to the process of gradually increasing the volume of emails sent from a new IP address. The process ensures that ISPs don't identify you as a spammer.

October 2021 - Zoho
Marketer view

Email marketer from Reddit answers warming up an email list after a long period of inactivity requires you to clean your list by removing inactive subscribers, start by sending to highly engaged users, and use personalized content to drive engagement.

July 2024 - Reddit
Marketer view

Email marketer from HubSpot answers IP warming is the process of gradually increasing the volume of email sent from a new IP address or domain to build a positive reputation with ISPs. It involves starting with a small number of emails and gradually increasing the volume over time.

August 2023 - HubSpot
Marketer view

Email marketer from Sender.net shares it's important to segment your list and begin by sending to your most engaged subscribers first. This helps ensure that your initial sends have high open and click rates, which signals to ISPs that your emails are wanted.

January 2024 - Sender.net
Marketer view

Email marketer from Email Geeks suggests to start with those engaged on the welcome email (opened or clicked), then actives on the game, then the others.

December 2024 - Email Geeks

What the experts say
4Expert 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.

February 2024 - 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.

October 2022 - Word to the Wise
Expert view

Expert from Email Geeks shares to start with the most recently engaged and work backwards. Tie it to people who are playing the game.

November 2021 - Email Geeks
Expert view

Expert from Email Geeks explains that machine learning filters don’t like change and have seen spammers trickle mail out over weeks or months and then send a giant send. She also questions what the normal daily / weekly send volumes are and the type of infrastructure used.

August 2022 - Email Geeks

What the documentation says
4Technical 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.

March 2021 - 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.

June 2021 - Twilio SendGrid
Technical article

Documentation from Google explains to start with a small volume of emails and gradually increase it over time. Monitor your sending reputation in Postmaster Tools and adjust your sending schedule accordingly.

February 2025 - Google
Technical article

Documentation from MailerQ answers to start with engaged users to prove trustworthiness to ISPs, and use a ramp up model to not exceed daily limits. Focus on a steady increase in volume with good email content and engagement.

July 2024 - MailerQ