Email Warm-Up

IP warming is the process of limiting the amount of sent mails at first from a mail server on a new IP address and then gradually growing your sending volume over the first few weeks. By this process, you build a good reputation and don't surprise the ISPs to block you eventually. ISPs are suspicious of mail handed to them by servers with little or no sending history; lots of spam comes to them that way. IP warming helps you avoid problems by allowing the sender to introduce themselves to the ISP in a measured way.

What is warm-up and why is it important?

Why should we follow the warm-up practice?

Internet Service Providers or Mailbox Providers take precautions when they detect an unfamiliar IP or sending domain. ISPs/MBPs put the IP and sending domain under high scrutiny to determine if the emails being sent from this IP and domain are spam or not.  This is a standard procedure associated with any new sending IPs, regardless of sender type. ISPs will carefully examine the volume of emails sent, the frequency at which they are sent, complaints, and bounce rates generated from these mailings. This process of examining these data points takes time and cannot be achieved in a day or two. Positive reputation metrics, built over time, will help you go a long way in a successful IP warming process. That’s why Insider recommends sending small volumes and starting to send to your highly engaged customers first.

What happens if we don’t follow the Warm-Up process?

In the “Email Marketing World'', it’s been seen that Spammers are sending from new IPs all the time they will burn through a pool of IPs until they get shut down and repeat the process on another pool of IPs.

As a result, ISPs treat traffic being sent from new IPs very carefully. They will block IPs from sending a large amount of email, Blacklisting organization gets active and they put your Ip and Domain in the Blacklisted category. In this way, your whole email marketing program may be derailed soon. So, it’s needless to say that how important it is to follow the warm-up process.

What will we achieve by following the Warm-Up process?

The primary goal is to let the ISPs know of what you're sending. *This ensures: 

• Building trust between the sending IPs and ISPs.
• Increases your brand’s reputation.
• Prevents you from being ‘Blocked’ or ‘Blacklisted’
• Increased chances of  email-delivery
• Builds a strong bridge between sender and receiver   

** Factors such as your overall list size, list quality, and subscriber engagement can influence the amount of time it takes for your IP address to be fully ramped up.

When will the warm-up process finish?

What to expect?

Let’s look at some of the pointers with respect to IP warming: 

• The warming-up process will probably take around 30- 50 days. It might take longer (or shorter) depending on:
  - The volume of emails you send out
  - The quality of your subscriber list
  - The frequency of sending out emails
• The process speeds up if you send out emails daily rather than weekly.
• If you rush your warm-up or do not plan it carefully, you might face problems in getting your email delivered to the inbox.
• Segment your subscriber base on the basis of the domain and then start targeting accordingly. This will help you analyze the campaign performance ISP-wise.
• Complaints: Spam traps, abuse, should be less than 0.1% during the first 30 days.
• Hard Bounce: It shouldn’t exceed a 0.1% rate during the first 30 days
• Unsubscribe: Shouldn’t exceed 0.10% during the first 30 days
• Subscriber Engagement: ISPs look for consistent volume and good data quality, where subscriber engagement is desirable. Focus on the open and click rate.
• Identify your engaged subscribers, which are those who open, click, and buy, in the following buckets, the warm-up from buckets 1, and 2, and so on...
  - Less than 30 days
  - 30-60 days
  - 60-90 days
  - 90-180 days
  - Over 180 days  
• Clean up your list by removing malformed domains, unknown users, and unengaged subscribers

How to segment users according to the warm-up plan

Conclusion

Avoid rushing the process of IP warming by sending more volume than recommended. We should avoid spending time identifying the most engaged subscribers and failing to mail these subscribers to build a positive reputation. Please resist this urge! It will not help in the long term. It is important to start mailing your highly engaged subscribers for the initial stages of IP warming. It helps to build a reputation and also shows ISPs that you are following the rules and best practices.

A recommended approach to warm up your Email Program

IS_wise warm-up program: Why is it recommended in the email world

IP warming and ramping up, along with following the best practices will help optimize your inbox delivery. But certain mailbox providers may require a more customized approach due to how they handle new traffic according to the set email acceptance threshold by them. Mailbox providers do not declare it publicly. The Insider team is your partner in this process, and will help you during this IP warming phase to position you for success.