What is Warming Up Email Queues?

This is the process of letting internet service providers (ISPs) and recipients get used to your email sending volumes and to build a positive sender reputation. If a recipient has never seen any email from your sending IP address and domains there will be no previous reputation so it is important to gradually build up the volume of emails you send over the first few weeks.

How to Warm Up your Email Queues

ISPs & recipients score the reputation of a sender based on the level of engagement with the emails they send. A sender with a good reputation is more likely to get their mail delivered to the recipient inbox rather than being marked as spam. Any sudden spikes or larges changes in behaviour can affect deliverability so it is best practice to build up your email volume over the first weeks and continue to gain positive reputation via positive recipient engagement.

Here are some steps to help you:

1. Before you start live mailings, ensure your SPF records set up correctly for your FROM sending domains
2. Estimate how many emails you plan to eventually send in a week and gradually ramp up to this number over a period of several weeks
3. Initially target mailings to your cleanest lists and most engaged recipients instead of sending to everyone straight away
4. In the first week we suggest sending no more than 5,000 emails, spread evenly across the week. 
5. Regularly check your overall bounce rate is not more than 10%, and particularly your hard bounce rate is lower than 5%
6. Ramp up to your target monthly send volume by no more than doubling your send volumes each week. Ideally try to smooth your send volume rather than sending 20,000 emails one day and then no emails for the rest of the week. A gradual and steady increase is advised
7. If you only send out a couple of mailings per month we recommend you don't send over 10,000 emails in one day

What are the advantages of Positive Reputation?

1. Emails are more likely to reach the inbox and be delivered more quickly
2. Less spam filtering scrutiny
3. Ability to send greater volumes
4. Images downloaded automatically for some email clients

A Positive Reputation is gained by sending emails to recipients who engage positively. Positive Engagement includes:

• Emails being opened, the more emails are opened the better for Positive Reputation
• Links in emails being clicked
• Emails being moved out of the spam folder into the inbox or other folder
• Recipients adding the sender's FROM address to their address book/safe senders list

What are the limitations of Negative Reputation?

1. Delivery not being prioritised therefore emails taking longer to be accepted at time of send
2. Recipients receiving emails later then expected
3. Emails going into the spam folder for recipients
4. Rate limiting on the number of emails that can be sent
5. Emails being totally rejected

Negative reputation is gained in multiple ways, the most prominent is by sending emails to recipients who engage negatively with emails from the sender. Negative engagement includes:

• Emails not being opened for a long period of time
• Emails being manually sent to the spam folder
• Blocking the sender's FROM address(es) or domain(s)
• Mailing continuously to non-existing addresses
• Clicking on the mark as spam button