IP Warmup: Why and How You Should Do It

Warming up your IP is crucial to ensuring healthy deliverability. It should be the first part of your greater email marketing strategy, as it lays the foundation for making sure your emails actually get opened. No matter how well-designed your emails will be or how well-segmented your lists are, having a bad sending reputation will mean those beautiful, targeted emails won’t be seen by your customers. Why? They’ll land in spam.

A quick refresh on the definition before we dive in:

IP warming is the process of slowly ramping up your sending volume over time on a new IP address. The goal is to establish a positive sending reputation with internet service providers (ISPs) like Gmail, Outlook, and Yahoo so your emails get delivered to the inbox.

IP warming is the process of slowly ramping up your sending volume over time, in order to establish a positive sending reputation.

Why warm up your IP?

Well, let’s paint a picture of what happens when you don’t warm up:

  • ISPs see a new brand - you - start to send emails on a new IP and begin assessing whether you’re trustworthy.
  • Maybe you’re in a rush to get an announcement out or you’re just amped to email subscribers, but you blast your whole list a few times instead of taking the time to send targeted emails to your segments. As a result, your subscribers start engaging less with your emails.
  • You continue to blast your list, including contacts who are becoming inactive.
  • ISPs start to doubt whether you’re a good sender, so they start sending your emails to spam or marking you as an untrustworthy sender.
  • You keep blasting your list.
  • ISPs start blocking you from sending email. It’s now more difficult for you to build a positive sending reputation.

Not ideal eh?

Many brands who switch to a new email service provider (ESP) don’t think about re-establishing their sending reputation - we get it, there’s a lot to think about! To avoid ending up in the position we just laid out, let’s dive into how you can build a positive sending reputation and maintain a healthy relationship with ISPs.

How to warm up the right way

1. Set up a subdomain

This is especially important if you’re sending a high volume of email, as each subdomain gives you a separate sending reputation. You can learn more about subdomains in our Why You Should Be Using a Subdomain post.

2. Strategize a sending plan

We’ve mentioned how important it is to send your first few emails out in chunks instead of blasting your whole list at once. But what does that actually look like? A good rule of thumb is to send to your highest-engaged contacts first, and slowly expanding from there to less engaged. Another way to think about it is to send to your contacts who are least likely to complain and bounce. Here’s what that might look like:

  • Week 1-2: Slowly ramp contacts who’ve engaged with an email in the past 30 days
  • Week 3-4: Send to contacts who’ve engaged in the last 60 days
  • Week 5-6: Expand to contacts who’ve been active in the last 90 days

Sparkpost has an in-depth sending plan that lays out the number of contacts you should send to over time - you can reference it when building your own but remember, each list is different!

Tip: Best practise recommends sending only to highly-engaged subscribers for the first 30 to 45 days until you have built up your reputation.

3. Monitor the deliverability of your campaigns & actively remove unengaged subscribers

It’s important to keep an eye on your deliverability as it shows how ISPs are responding to you as a sender. Maintaining consistency in terms of your ramp up volume and frequency of sending email will help you establish a positive reputation faster. The key here is to send daily or weekly. Anything less will mean it’ll take longer to warm up. You should also aim to frequently remove inactive subscribers from your sending list - we’ve already discussed what happens when you send to inactives 😉

Sending strategies based on industry

Your sending plan doesn’t have to be based on engagement alone - there are smart ways you can send to segments based on your industry. Here are some examples:

Try sending to your highest spend and most engaged customers first. You can create segments of customers who fall into purchase value is above X and active in the last X days, and create your sending plan from there.

Events & Music
You can send to attendees who have purchased the most tickets and have been actively engaging first. Try creating segments based on attendees who’ve purchased more than X tickets and have engaged in the last X days. If you don’t have access to this data, you can send based on distance from your venue.

Media & Publishing
This is the most similar to a generic sending plan, since the industry is based on email opens. You are safe to stick to a ‘most engaged in the past 30 days, 60, 90’ sending plan.

Wrap Up

Approaching your first few emails with a warm up strategy is key to long-term email marketing success. From creating a subdomain, to building out a consistent sending plan, you’re one step closer to establishing a healthy sending reputation.