What are the best practices for dedicated IP warm-up?

Key findings

• Gradual Volume Increase: A structured, incremental increase in email volume over several weeks is essential. Starting with low volumes and slowly ramping up helps ISPs build a positive profile for your IP.
• Audience Segmentation: Prioritize sending to your most engaged subscribers first. This strategy generates positive engagement signals, which are crucial for reputation building.
• Consistent Sending: Maintain consistent sending patterns throughout the warm-up period, both in terms of volume and frequency.
• Content Quality: Send high-quality, engaging content that recipients expect and value. This minimizes complaints and maximizes positive interactions like opens and clicks.
• Monitoring Metrics: Continuously monitor key email metrics such as open rates, click-through rates, bounce rates, and complaint rates to assess reputation health.

Key considerations

• Patience is Key: The warm-up process takes time, typically four to eight weeks, and rushing it can be detrimental. Sticking to the plan is crucial for long-term success.
• Expect Deferrals: It is common to experience some temporary deferrals during the initial weeks of warming. These usually resolve as the IP reputation builds.
• Automation Management: Consider whether to include automated flows in your warm-up volume, or if they should be temporarily delayed or sent via a shared pool, if available, until the dedicated IP is fully warmed. This is a common challenge for those migrating to a new ESP.
• ISP-Specific Strategies: Some ISPs, like Gmail, Hotmail (Outlook), and Verizon Media Group (AOL, Yahoo, Verizon), may require specific volume adjustments or remediation processes during warm-up. For detailed guidance on this, refer to our guide on ISP-specific IP warming strategies.
• Understanding Schedules: Familiarize yourself with typical IP warm-up schedules, such as those provided by Iterable, to set realistic expectations.

Key opinions

• Domain-Based Segmentation: Many marketers recommend segmenting sends by major domains like Gmail, Hotmail/Outlook, and Verizon Media Group (AOL, Yahoo, Verizon) to better manage volume and monitor domain-specific performance.
• Engaged Audience First: A common strategy is to start sending to the most engaged recipients, such as those active within a 30-day window, and gradually expand this audience.
• Triggered Emails as Initial Volume: Starting the warm-up with low-volume, high-engagement triggered emails (e.g., transactional emails) can help establish a positive sending pattern before introducing marketing campaigns.
• Open Rate as Reputation Indicator: Some marketers use a unique open rate (e.g., 15% or greater) as a benchmark to determine if they are successfully building reputation and can increase sending volume.

Key considerations

• Adherence to Plan: Marketers emphasize the difficulty and importance of strictly adhering to the warm-up schedule, advising patience as results improve incrementally.
• Handling Automated Sends: A key question is whether total send amounts include automated flows and if these should be turned off or rerouted to a shared IP pool until the warm-up is complete. This relates to how email sending platforms can be consolidated.
• Expect Initial Deferrals: Initial deferrals are a normal part of the process, and marketers advise not to panic as long as the volume is controlled and recipients are engaged.
• Leveraging ESP Resources: Many marketers find it beneficial to utilize their ESP's deliverability support or guides during the warm-up period for guidance and troubleshooting.

Key opinions

• Domain-Specific Warming: Experts strongly advocate for segmenting email sends based on recipient domains (e.g., Gmail, Hotmail/Outlook, Yahoo). This allows for targeted volume control and performance monitoring for each major ISP, which is critical for Gmail and Microsoft deliverability.
• Prioritizing Engaged Lists: The consensus among experts is to initiate warm-up by sending to the most active segments of your list, gradually expanding to broader audiences as reputation solidifies. This ensures positive engagement signals early on.
• Sending Duration Matters: Beyond just daily volume, the duration over which that volume is sent is crucial. Spreading sends throughout the day (e.g., 100,000 emails at 10,000 per hour) can be more effective than sending in bursts.
• Anticipate Deferrals: It's normal to encounter deferrals, particularly from major ISPs like Hotmail/Outlook, during the initial weeks. These are often temporary as ISPs assess the new IP.

Key considerations

• Remediation and Waiting Periods: Experts note that progress through a warm-up schedule might pause if remediation is needed from an ISP (e.g., Hotmail). Understanding when and how to engage with ISP postmasters or support is key.
• Comprehensive Volume Tracking: All mail sent from the dedicated IP, including transactional emails and automated flows, must be accounted for within the daily volume limits of the warm-up plan. This helps in avoiding deliverability issues from insufficient warm-up.
• Leveraging ESP Resources: Many ESPs offer specialized deliverability personnel or services to assist with IP warm-up. Utilizing these resources can be highly beneficial, especially for complex sending environments. For more information, see Mailchimp's guide on dedicated IPs.

Key findings

• Multi-Week Process: IP warm-up typically spans four to eight weeks, requiring senders to gradually increase their email volume over this period. This timeframe allows ISPs sufficient data to assess sending patterns.
• Volume Increment Guidelines: Documentation often provides specific daily or weekly volume increment percentages or absolute numbers. These schedules are designed to prevent sudden volume spikes that could trigger spam filters.
• Engaged Subscriber Focus: It is consistently recommended to send to your most engaged subscribers first. This strategy ensures high open and click rates and low complaint rates, which are critical for reputation building.
• Monitor Deliverability Metrics: Regular monitoring of deliverability metrics, including bounces, complaints, and blocklist (or blacklist) listings, is highlighted as essential. This proactive approach helps identify and address issues promptly.

Key considerations

• Strict Schedule Adherence: Documentation stresses the importance of adhering to the warm-up schedule without attempting to accelerate the process, as premature volume increases can negatively impact reputation.
• Transactional vs. Marketing Emails: Some guides suggest starting with transactional emails due to their typically higher engagement and lower complaint rates, before gradually incorporating marketing emails.
• Domain and IP Warming Synergy: While the focus is on IP warming, documentation often implicitly (or explicitly) notes that domain reputation is also established in parallel, emphasizing the need for consistent sending practices across both.
• Automated Completion: Some platforms, like Klaviyo, explain that the IP warming process automatically completes once the expected email volume is consistently sent through the dedicated IP, indicating a successful ramp-up.