Guide for IP & domain warming

IP warming

IP warming is crucial for establishing a positive reputation for a new IP address. This process involves gradually increasing the volume of emails sent over time, with the goal of building trust with Internet Service Providers (ISPs).

By ramping up email volume slowly, you allow the ISPs to monitor your sending behavior. This helps ensure that your emails are not harmful or unwanted, which in turn improves deliverability and protects your sender reputation.

Appropriately done, IP warming increases the likelihood that your emails land in recipients' inboxes.

Several factors contribute to a successful IP warming process:

• Understand your estimated maximum daily and monthly volumes – This helps identify a target value for ramping and how many dedicated IPs to allocate to this domain or subdomain.
• Prepare your target audience during the warming process – It is recommended to start the warming process by targeting your most engaged audience or most recent signups. This increases the odds of positive engagement, such as opens and click-throughs.
• Use a warming plan that segments ISPs – Even when sending low volumes, avoid using a single campaign that targets all ISPs at once. Instead, structure your sends so that each ISP receives a controlled number of emails. This prevents overloading any one provider and helps build a balanced sending reputation.

Each ISP maintains its reputation and should be treated as a separate entity. While a sender’s reputation is often similar across ISPs, this is not always true.

Additionally, not all ISPs provide public tools to measure the success of IP warming. The two significant ISPs that do offer visibility into sender reputation are:

• Google Postmaster Tools
• Microsoft SNDS

Sample IP warming plan

You can use the sample below to gradually scale your daily send volume across three weeks.

Week 1	Volume per ISP	Week 2	Volume per ISP	Week 3	Volume per ISP
Day 1	50	Day 8	900	Day 15	10,000
Day 2	75	Day 9	1,250	Day 16	15,000
Day 3	125	Day 10	1,750	Day 17	27,500
Day 4	200	Day 11	2,500	Day 18	40,000
Day 5	300	Day 12	3,500	Day 19	75,000
Day 6	450	Day 13	5,000	Day 20	125,000
Day 7	650	Day 14	7,500	Day 21	200,000

Domain warming

Domain or subdomain warming is similar to IP warming and is often performed in tandem. When a new IP and a new domain are being warmed together, the IP warming plan takes precedence, as it typically follows a more cautious and slower ramp-up.

Sometimes, a new domain may need to be warmed while being associated with an already warmed-up dedicated or shared IP. In this scenario, domain warming can proceed moderately faster than IP warming. This is because the existing IP's residual reputation helps support the new domain's neutral reputation.

Sample domain warming plan

The sample below outlines a domain warming plan used when the domain is mapped to a pre-warmed IP. While volumes can ramp more aggressively than during IP warming, they should still follow a controlled and gradual increase.

Week 1	Volume per ISP	Week 2	Volume per ISP	Week 3	Volume per ISP
Day 1	100	Day 8	2,750	Day 15	200,000
Day 2	150	Day 9	5,000	Day 16	300,000
Day 3	250	Day 10	10,000	Day 17	450,000
Day 4	400	Day 11	20,000	Day 18	650,000
Day 5	600	Day 12	40,000	Day 19	900,000
Day 6	900	Day 13	75,000	Day 20	1,250,000
Day 7	1,500	Day 14	125,000	Day 21	1,750,000

Additional notes & keys to success

General considerations

The sample figures above provide high-level guidance for safe volume ramping. Actual volumes may vary depending on the engagement level of your target audience. However, if there is any doubt about list health, ramping more cautiously is always safer. The more engaged and healthy your active audience is, the more flexibility your email program will have when increasing volume.

During any warming period, monitoring engagement metrics after each deployment is essential. Use campaign or insights reports to track changes in opens and clicks and negative metrics such as hard bounces, soft bounces, unsubscribes, and spam complaints. Historical benchmarks can help you determine your target open and click rates over time.

The table below provides general threshold guidelines for monitoring negative engagement.

Hard bounce rate	Soft bounce rate	Unsubscribe rate	Spam report rate
<2%	<2%	1% or less	0.1% or less

ISP-specific considerations

Each ISP considers different key metrics regarding warming or ramping up volume.

From a Gmail perspective, domain reputation carries more weight than IP reputation. This is mainly because Google understands the widespread use of shared IPs, auto-warming processes, and load-balanced IP pools. It's vital to monitor Google Postmaster Tools (GPT) to ensure complaint rates remain within acceptable thresholds (generally <0.3%). GPT’s updated interface also includes checkmarks to indicate compliance with Gmail’s sender requirements.

Microsoft, on the other hand, places greater emphasis on IP reputation. This is evident from the Microsoft SNDS tool, where IP reputation is the primary metric. Shared or dedicated IPs are used by reputable senders, as damage to the IP reputation can negatively affect all associated senders. In addition, SNDS includes proprietary data such as spam trap hits, which are Microsoft-specific and can significantly impact sender reputation.

Yahoo no longer provides a public-facing tool for reputation metrics. However, its filtering behavior aligns closely with Gmail and Microsoft. Yahoo tends to weigh IP and domain reputation more evenly, but emphasizes positive engagement, especially clicks. Their filters evaluate engagement over specific time windows, so strong performance during initial deployments can improve future deliverability. Conversely, spikes in negative signals, such as unsubscribes or complaints, can quickly degrade reputation and affect upcoming sends.

Blueshift IP/domain warming setup guide

We recommend creating dedicated campaigns and segments targeting specific audiences and volumes to begin IP or domain warming. This guide outlines the recommended steps for setting up the warming campaigns and segments.

While other approaches may also work, the method described here is our preferred best practice.

Before you begin:

1. You should have a campaign template ready (ideally already created in your account) that can be reused over multiple days. The more engaging and updated the content, the fewer individual warming campaigns you’ll need to create.
2. Ensure your target audience has already been imported into your account. This allows the segments you create to reflect accurate audience counts.

Warming segment setup – part 1

• Navigate to Orchestration → Segments from the left navigation panel.
• Click the +Segment button in the top right corner of the screen.
• Select Basic Segment (you can also use Advanced Segment) and enter a name for the new segment.

• Set user attribute filters for the email domain. Use match any if multiple domains should be included.
• Click Save and Continue to complete setting up the segment. The matching users count will be displayed on the right side panel.

Warming campaign setup – part 1

• Navigate to Orchestration → Journeys → Campaigns from the left navigation panel.
• Click the +Campaign button in the top right corner of the screen.
• Select Recurring campaign and enter a name for the new campaign.

• Select the segment created earlier as the target audience for this campaign.
• Choose email as a trigger and select an email template.

• Navigate to the Properties tab at the top left corner of the screen.
• Set an Execution Schedule, i.e., date and time. Campaign duration will depend on your content and audience size. You can leave the end date blank to run the campaign indefinitely, but pause it manually once the warming period is complete.

• Click Messaging Preferences and enter a value for the 'Limit number of message(s) for this campaign to' textbox. If you're following the sample warming plan above, enter 50.

• Click Save in the top right corner of the screen to complete the campaign creation.

Warming segment setup – part 2

• Navigate to Orchestration → Segments from the left navigation panel.
• Search and open the segment created earlier.
• Click Messaging and add the campaign created earlier to filter the segment further by excluding the users who have already received the email.
  • Select the grouping as NONE. 
  • Select Email as the channel and Sent as the action.
  • Choose the campaign name.

• Click Save and Continue to complete editing the segment.

Warming campaign setup – part 2

• Navigate back to the campaign.
• Click Save, then Validate the campaign using the buttons in the top right corner.
• Click the Launch button and confirm the prompt regarding the schedule and limits to complete the campaign launch.

Your warming campaign is now live! You can repeat these steps for other ISPs you plan to warm.