What are the best practices and schedules for warming up an IP address for email sending?

Summary

IP warming is the gradual process of increasing email volume from a new IP address to establish a positive sending reputation. Experts and documentation recommend starting with a small segment of highly engaged users, sending quality content, and then incrementally increasing volume while closely monitoring deliverability metrics like bounce rates and spam complaints. Authentication (SPF, DKIM, DMARC) is crucial, as is adapting the strategy based on specific sending scenarios and feedback from mailbox providers. It's also important to view the process as a form of communication with mailbox providers.

Key findings

  • Engage First: Start with a small group of your most engaged subscribers to establish a baseline of positive interactions.
  • Gradual Growth: Increase sending volume gradually to avoid triggering spam filters and allow mailbox providers to assess your reputation.
  • Monitor Metrics: Continuously monitor bounce rates, spam complaints, and engagement metrics to identify and address potential deliverability issues.
  • Authenticate Email: Implement SPF, DKIM, and DMARC to verify your sending identity and improve deliverability.
  • Communicate with Providers: View the warming process as a form of communication with mailbox providers, demonstrating that you send wanted mail to real users.

Key considerations

  • Conservative vs. Aggressive: Determine an appropriate growth rate, considering factors like your specific sending situation and risk tolerance.
  • Scenario Specifics: Adjust your approach based on whether you're warming a cold IP or migrating an existing domain.
  • ESP Data: Consider consulting with your ESP to leverage their data on effective warming strategies for their platform.
  • Respond to Issues: Be prepared to reduce sending volume if you encounter deliverability problems during the warm-up process ('back off').
  • Define Goals: Establish clear goals for your mailings and how to measure against them

What email marketers say
9Marketer opinions

The consensus on warming up an IP address for email sending involves starting with a small, highly engaged segment of your audience and gradually increasing volume. Monitoring key metrics like bounce rates, spam complaints, and engagement (opens, clicks) is crucial to adjusting your schedule. Sending quality content, focusing on list hygiene, and potentially starting with transactional emails are also recommended to build a positive sending reputation.

Key opinions

  • Start Small: Begin with a small segment of your most engaged subscribers to ensure positive initial interactions.
  • Gradual Increase: Incrementally increase sending volume over time to avoid triggering spam filters.
  • Monitor Metrics: Closely track bounce rates, spam complaints, and engagement metrics (opens, clicks) to identify and address deliverability issues.
  • Quality Content: Send relevant, valuable content that recipients want to receive to improve engagement.
  • List Hygiene: Maintain a clean email list by removing inactive or unengaged subscribers to improve your sender reputation.

Key considerations

  • Engagement Levels: Segment your audience based on engagement levels to target your most responsive subscribers during the initial warm-up phase.
  • Schedule Adjustment: Be prepared to adjust your sending schedule based on the performance of your campaigns and any deliverability issues that arise.
  • Transactional First: Consider starting with transactional emails to establish a base reputation before sending marketing emails.
  • Reputation Monitoring: Continuously monitor your sender reputation with mailbox providers to identify and address any issues promptly.
  • Double Volume (with caution): One strategy suggests doubling volume daily, but it's critical to monitor carefully and slow down if bounces exceed 5%.
Marketer view

Email marketer from Litmus emphasizes the importance of a methodical IP warm-up, they suggest starting with a small segment of your most engaged subscribers and gradually increasing volume. Closely monitor deliverability metrics and adjust the schedule as needed to avoid issues like bounces and spam complaints.

January 2025 - Litmus
Marketer view

Email marketer from HubSpot recommends segmenting your contacts by engagement level and gradually increase the volume of emails you send to each segment, and closely monitor your sender reputation.

January 2023 - HubSpot
Marketer view

Email marketer from Reddit explains that a common strategy is to double your volume every day for the first week. Then, slow it down. Monitor your reputation, and if you see bounces increase beyond 5%, then reduce your volume until the bounces normalize.

October 2022 - Reddit
Marketer view

Email marketer from ActiveCampaign shares that a successful email warm-up is critical. Begin by sending small batches of emails to engaged contacts, gradually increasing volume based on open and click rates. Watch out for deliverability issues and modify your approach accordingly.

March 2022 - ActiveCampaign
Marketer view

Email marketer from EmailOnAcid shares that starting with a small segment of your most engaged subscribers is crucial and monitor engagement closely. The warm-up process should be tailored to your specific sending situation, so adapt the schedule if you see issues like bounces or spam complaints. Aim for gradual, steady increases.

November 2023 - EmailOnAcid
Marketer view

Email marketer from Mailchimp recommends segmenting your audience and starting with highly engaged subscribers. Gradually increase the volume and frequency of emails while closely monitoring your bounce rates, unsubscribe rates, and spam complaints. Adjust your strategy as you gain more data about your sending reputation.

February 2025 - Mailchimp
Marketer view

Email marketer from SendPulse shares that IP warm-up is important. Start small and increase daily volume with your most engaged users first and monitor engagement for issues.

November 2021 - SendPulse
Marketer view

Email marketer from Quora suggests starting with sending transactional emails first, then gradually introducing marketing emails. Focus on building a good reputation by sending quality content and maintaining a clean list.

January 2025 - Quora
Marketer view

Email marketer from Neil Patel explains that a proper IP warm-up is essential for email deliverability. He suggests starting with your best contacts and gradually increasing volume based on positive engagement. Monitor key metrics and adjust your sending schedule if you see any warning signs.

May 2021 - Neil Patel

What the experts say
13Expert opinions

Experts emphasize the importance of a gradual IP warming process. This involves starting with a low sending volume to highly engaged users and carefully increasing it over time, with a focus on positive recipient engagement. Strategies should be tailored to specific sending scenarios (e.g., cold IP vs. domain migration). Close monitoring of deliverability metrics like bounce and complaint rates is essential. Authentication (SPF, DKIM, DMARC) setup is critical and consulting ESP data is recommended. Some advocate a conservative approach, and it's crucial to view warming as communicating with mailbox providers to demonstrate sender trustworthiness.

Key opinions

  • Start with Engagement: Focus on sending to recipients who actively want your email and are likely to engage positively.
  • Gradual Increase: Incrementally raise sending volume over a defined period, allowing mailbox providers to assess your reputation.
  • Monitor Deliverability: Closely track metrics like bounce rates and complaint rates to identify and address potential issues promptly.
  • Authentication: Implement email authentication protocols (SPF, DKIM, DMARC) to verify your identity and improve deliverability.
  • Warming = Communication: Think of warming as establishing communication with mailbox providers about the content.

Key considerations

  • Conservative vs. Aggressive: Determine an appropriate growth rate (e.g., 30-50% daily, doubling weekly) based on your specific sending situation and risk tolerance, with some experts advocating a more conservative approach.
  • Specific Scenarios: Adjust your warm-up strategy depending on whether you are warming a completely cold IP address or migrating an existing domain.
  • Data from ESPs: Consider consulting with your ESP to leverage their data on effective warm-up strategies for their platform.
  • Back Off If Needed: Be prepared to reduce sending volume ('back off') if you encounter deliverability issues during the warm-up process.
  • Defined Goals: Before starting to warm-up your IP, define the goals of your mailing and how you will measure against them.
Expert view

Expert from Email Geeks recommends Jennifer Lantz's guide to IP warming: <https://www.spamresource.com/2022/01/the-definitive-guide-to-ip-warming.html>.

April 2023 - Email Geeks
Expert view

Expert from Email Geeks shares a SendGrid help document they've used before for IP warming schedules: <https://sendgrid.com/en-us/resource/email-guide-ip-warm-up#chapter-5-sample-transactional-email-schedule>

January 2025 - Email Geeks
Expert view

Expert from Email Geeks shares their general information and reasoning behind IP warming, providing links to their articles: <https://wordtothewise.com/2014/04/warmup-ip-addresses/> and <https://wordtothewise.com/2017/09/warmup-advice-gmail/> and <https://wordtothewise.com/2024/06/warmup-is-communication/>.

November 2022 - Email Geeks
Expert view

Expert from Email Geeks states they are more conservative with IPs and also defers to ESPs due to their greater data on current successful strategies.

October 2023 - Email Geeks
Expert view

Expert from Word to the Wise explains that warming is a form of communication with mailbox providers. The goal is to show providers that you send wanted mail to real, engaged users.

January 2023 - Word to the Wise
Expert view

Expert from Email Geeks responds to question about issues during IP warming, suggesting to 'back off; slow down'.

April 2021 - Email Geeks
Expert view

Expert from Email Geeks explains that they generally target a 30% daily growth but will push to 50% if performance is good and will sometimes suggest 0% growth or a pull back on growth.

October 2021 - Email Geeks
Expert view

Expert from Email Geeks explains the distinction between warming a cold IP with a new domain versus just moving domains around, highlighting different communication goals.

September 2021 - Email Geeks
Expert view

Expert from Word to the Wise explains that IP warming involves carefully sending email to real people who want it so they will engage with it. You should start with low volume and increase slowly, focusing on engagement. Don't worry too much about specific daily or weekly numbers; focus on getting positive signals from your recipients.

August 2022 - Word to the Wise
Expert view

Expert from Email Geeks recommends the Salesforce article he helped develop: <https://help.salesforce.com/s/articleView?id=sf.mc_es_ip_address_warming.htm&amp;type=5>.

November 2022 - Email Geeks
Expert view

Expert from Spam Resource provides a definitive guide to IP warming which discusses defining your goals, understanding reputation metrics, setting up authentication (SPF, DKIM, DMARC), segmenting sending volume and gradually increasing volume and monitoring key metrics like bounce rates and complaint rates.

August 2022 - Spam Resource
Expert view

Expert from Email Geeks suggests limiting growth to no more than double daily volume week over week.

December 2023 - Email Geeks
Expert view

Expert from Word to the Wise shares warmup advice specific to Gmail. It focuses on sending wanted mail to real subscribers who are likely to engage. It focuses on good list hygiene, engagement and authentication

August 2023 - Word to the Wise

What the documentation says
5Technical articles

Email sending documentation consistently describes IP warming as a process of gradually increasing email volume from a new IP to build a positive sending reputation with ISPs. The core strategy involves starting with low volumes targeted at highly engaged users, then incrementally scaling sends while closely monitoring deliverability metrics (bounces, complaints, blocklist status) and adjusting sending schedules accordingly. Authentication and adherence to sender guidelines are also crucial.

Key findings

  • Gradual Volume Increase: A gradual increase in email volume is the foundation of IP warming.
  • Engaged Subscribers First: Start by sending to your most engaged subscribers.
  • Monitor Deliverability: Closely monitor bounce rates, spam complaints, and blocklist status.
  • Build Sending Reputation: The goal is to build a positive sending reputation.

Key considerations

  • Authentication: Ensure proper email authentication (SPF, DKIM, DMARC).
  • Throttling: Review and adhere to best practices for throttling email sending rates.
  • Sender Guidelines: Adhere to the specific sender guidelines of each ISP (e.g., Google).
  • Consistent Volume: Strive for a consistent sending volume.
Technical article

Documentation from Google Postmaster Tools mentions gradually increasing sending volume is important. They emphasize the need to authenticate your emails and adhere to their sender guidelines to establish a positive reputation. Monitor your reputation using their tools and adapt based on the data.

December 2021 - Google
Technical article

Documentation from SparkPost outlines that IP warm-up is a strategy to establish a good sending reputation. The best practice involves beginning with small, targeted sends to engaged users and increasing volume gradually as your reputation improves. They advise close monitoring of bounce rates, spam complaints, and blocklist status.

May 2024 - SparkPost
Technical article

Documentation from SendGrid explains that IP warming is the process of gradually increasing the volume of email sent from a new IP address to establish a positive sending reputation with ISPs. They recommend starting with low volume and gradually increasing it daily or weekly, monitoring deliverability and engagement metrics to adjust the schedule as needed.

August 2023 - SendGrid
Technical article

Documentation from Amazon SES outlines IP warm-up as a key step. They suggest beginning with your highest-quality email and steadily increasing volume. Monitoring bounce rates and complaints is vital for adjusting your sending schedule and maintaining a positive reputation. Review best practices on throttling your email sending rates.

January 2022 - Amazon SES
Technical article

Documentation from Mailjet explains that warming up an IP address involves steadily increasing your sending volume over a period of time. They suggest starting by sending to your most engaged subscribers and scaling gradually. Aim for consistent volume and monitor your sender reputation closely.

December 2021 - Mailjet