Warm Up Your Sending Domain Reputation

Your sending domain needs to have a good sending reputation or messages will never make it to your contact's inboxes. A warm up strategy can be used to help improve the sending reputation of a private sending domain.

Gmail tracks your sending domain's contact engagement record and uses this to assign a reputation. While other providers have traditionally used IP-based tracking, they're also starting to associate sending reputation with domains. When you send to contacts who are engaged and opted-in, your domain reputation should be good with these providers. But if a service provider receives a lot of complaints, particularly over a short period of time, your reputation will be damaged. A high number of bounces and a low open or click rate can also damage your reputation.

When you start sending from a new domain, you have no reputation and will need a warm up plan to establish a good one. When you have no reputation, sending volume is also heavily considered. If a provider suddenly sees a high-volume of activity from a new domain, it's likely to mark your messages as spam. This will damage your reputation and possibly get your domain marked as a spammer. While it's tempting to send to as many of your most engaged contacts as possible right away, a warm up should be gradual.

Whether you have no reputation or a bad one, implementing a plan where you send to opted-in contacts who engage with your messages can help establish a good reputation. You can only warm up one service at a time, so if you need to warm up your domain reputation with multiple providers you will need to run multiple warm up plans. For example, you would need separate Gmail and Hotmail plans.

Determine Your Total Sending Volume

The success of a warm up plan is contingent upon gradually sending messages to all of your opted-in contacts who use the email service that you have issue with. First, you need to figure out how many contacts you have to work with. When you know the total number of contacts that can be sent to, you can use engagement metrics to divide these contacts into groups.

  1. Determine what email service you want to warm up. For example, Gmail.

    If you want to warm up more than one, you will need to engage in a separate warm up plan for each.

  2. Calculate the total number of opted-in contacts you have emailed on this service in the past 2 years.
  3. Find the number in this table that is closest to your total number of opted-in contacts, rounding down if necessary.

    Identify the number of groups you'll use in your plan by looking in the second column of this table.

    Table 1.
    Number of Contacts Total Number of Sends To Complete Warm Up
    20 1
    40 2
    80 3
    160 4
    320 5
    640 6
    1,280 7
    2,560 8
    5,120 9
    10,240 10
    20,480 11
    40,960 12
    81,920 13
  4. Continue to the next section to learn how to group contacts.

Identify And Group Engaged Contacts

Now that you know how many groups of contacts you will use, we need to make sure your smallest groups have your most engaged contacts. Sending to your most engaged contacts first will boost a domain's warm up rate. To do this, you will use historical click and open metrics from your previous ESP to determine contact engagement.

  1. First, download all of the contacts you will include in the warm up plan.

    When you download these contacts, make sure you have click and open data available. We recommend using click through rate and/or click rate to sort contacts. If you don't have click metrics, you can use open rate.

  2. Identify contacts with:
    • a click through rate of 2.5% or higher
    • a click rate of 10% or higher
    and move them to the top of the list.
  3. Sort this group of contacts from highest engagement to lowest engagement based on percentages.
  4. Sort the rest of your contacts from highest open rate to lowest open rate.
  5. Add a new column to the file called service_group_name.

    Replace service with the email service you're sending your warm up plan emails to. For example, gmail_group_name.

  6. Use the service_group_name column to assign your contacts to groups.

    Start with the first contact and assign from the top to the bottom of the list based on the numbers in this table. For example, the 20-most-engaged contacts should be assigned A in the gmail_group_name column. The 40-second-most-engaged contacts should be assigned B in the gmail_group_name column. And so on.

    Table 2.
    Contact Numbers Group Name
    1–20 A
    21–40 B
    41 –80 C
    81 –160 D
    161 –320 E
    321 –640 F
    641 –1,280 G
    1,281 –2,560 H
    2,561 –5,120 I
    5,121 –10,240 J
    10,241 –20,480 K
    20,481–40,960 L
    40,961 –81,920 M
  7. Create a Bronto contact field to store the engagement information.

    The Bronto field name must be an exact match to the service_group_name column heading in your contact import file or the data will not be imported properly. Once imported, you will use this field to create segments you can use to send strategically.

    The correct Type for this field is Text.

  8. Upload your contact file into Bronto using the Add or Update Contacts option.

Send Strategically

After your contacts are in Bronto you can create segments and use them to implement your warm up plan. For most people, sending a new warm up message once per day works best. However, this frequency can be increased when your warm up plan is going well. When you run into engagement issues, stop sending and try to troubleshoot what caused the issue before you resume sending in order to avoid further damaging your reputation.

  1. Ensure that any automated emails are turned off.
  2. Use the service_group_name contact field to create a unique segment for each group.

    When you create each segment, make sure to use Text for the contact field type, Is for the operators, and Group Name (for example A) for the value as your segment criteria. Make sure each segment matches the total number of contacts that should be in the segment. For example, if group A isn't a group of 20 contacts, something went wrong either when you updated or imported your contact file.

  3. Send to segment A, which will target your 20 most engaged contacts.
  4. Wait 1 day and check the contact engagement.

    You can use Bronto's delivery report to look at engagement. If your click and open rates were high and your bounce and unsubscribe rates were low, engagement is good and you can move forward with the warm up plan.

    If engagement isn't good, don't resend to any contacts who haven't engaged. Also, consider waiting to send the next message to allow more time for contact engagement.

  5. When you're comfortable with engagement from your first send, send a message to segment B.

    This should be your next 40 most engaged contacts.

    • If you typically send messages daily, send a new message to contacts on segment A who engaged with your last message and the same message to segment B.
    • If you're typically a weekly sender, send the same message to segment B.
  6. Wait 1 day and check contact engagement for segment B on your delivery report.

    If engagement is good then continue to send. If engagement is poor, make sure you don't resend to problematic contacts.

  7. When you're comfortable with engagement from your last send, send a message to segment C.
    • If you're a daily sender, send a new message to the previously engaged contacts from segments A and B and the same message to segment C.
    • If you're a weekly sender, send the same message to segment C.
  8. Continue to check contact engagement and to double your sending volume with each send until you've sent to every segment.

    Daily senders should send to all previously-engaged warm up contacts every day. Weekly senders can send to all previously-engaged warm up contacts after 1 week of warm up sending.

    Closely monitor your contact engagement and sending reputation with each send and stop sending and regroup as soon as you see a negative trend. If you see your open rate plummet –particularly to less than 1%, it's possible that your reputation has crashed, but this may be temporary. Continue sending for 2 more days to 2 additional segments and see if the open rate rebounds. If not, go back to the last most successful segment send and try again. If you catch and fix the issue quickly, it will be much easier to recover your reputation.

    Things to consider:
    • As sends start to include less engaged contacts, your open rate will naturally decline. To reestablish a healthy open rate, begin sending to only engaged contacts. You can then follow a 90:10 (engaged:unengaged) mix rule to start introducing unengaged contacts in each send. If you see a significant drop-off, send to a smaller portion of your unengaged list. Over time, you may want to stop sending to some of these unengaged contacts or pursue a re-opt-in or last chance campaign.
    • Are you sending to the same non-engaged contacts again and again? Filter out contacts who don't engage with your warm up messages as you start resending to contacts.
    • Are you sending too many messages too frequently so the email provider marks your messages as spam? If a provider doesn't trust you and you send "too frequently" your contacts will never have a chance to engage because your messages will go straight to spam. If you see a high bounce rate, try sending to smaller groups of engaged contacts and gradually increase your sending volume and frequency as your reputation improves.
    • Are contacts not engaging with your messages because of an ineffective subject line? If you aren't seeing a lot of bounces or complaints, but your open rate is still low, consider adjusting your subject line.
    • Does your message contain unique content and a strong call to action? Your goal is to drive as many opens and clicks during the warm up period in order to build your reputation.

    If engagement continues to be good and your domain's reputation shows improvement, consider accelerating your sending strategy to more than once per day.

  9. Continue to check your domain's reputation as you warm it up. When your domain reputation is high again, you can continue normal (responsible) sending practices.
Note: If you don't have engagement metrics to go by, you can still follow this plan by just sending to contacts who use the service provider you need to warm up.
  • Typical sending cadence is once per day. This cadence can be accelerated if things are going well, or slowed down if you run into issues. You can send messages every 4 hours, up to 6 times per day. Keep in mind that you want to get as many opens and clicks at this time and deviating from your normal sending cadence can result in lower engagement stats.
  • Make sure that your earliest sends are to your most recently engaged contacts. When you don't have contact engagement information, send to any contacts but make sure to closely monitor the results of each send.
  • Daily senders can resend to previously-engaged warm up contacts every day, as long as these contacts are sent a new message.
  • Weekly senders can resend to previously-engaged warm up contacts after 1 week.
  • When you resend to contacts during the warm up plan, those contacts should not be counted in the total number for the day.
  • Turn on automated emails after you complete your domain warm up. The warm up is complete when you have sent to all engaged contacts consistently.