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Warmup your domain and get in the good books of ISPs

Everyone always wants to know what they need to do to land in a supporter's inbox without realizing there are actually a series of things to do or to be aware of before even pressing the send button. We are here to tell you what those things are!

December 20, 2022
3 min read

What is a domain warmup?

So you’ve just migrated from your previous email program to NationBuilder and you’re keen to start sending emails to your entire emailable database, ASAP? Let’s hit the brakes for a second and first talk about warming up your domain. This is the initial crucial step when setting your email programme up for success. 

Put simply, a warmup means you are in the early stages of a relationship with Internet Service Providers (ISPs) - the Gmail, Hotmail and Yahoo, etc of the world. By warming up your domain, you are showing them that you are a legitimate sender and not sending harmful material - in other words, that you are not sending spammy content.

Establish a sending reputation

However, this means you need to work your way up and build trust so that ISPs know you are the real deal - and that takes time. You may have heard the famous quote by Kevin Plank: “trust is built in drops and lost in buckets”. Once broken, trust cannot always be restored overnight. This logic also checks out for your domain’s relationship with ISPs. 

Say you suddenly go from sending zero emails to 1,000,000 from one day to the next, then most providers will assume that you have not organically grown your list - which is one key prerequisite of an authentic sender - since they have no historical data to help them understand if you are targeting users whose consent you’ve acquired. Regularly sending to a gradually growing volume of supporters who you know are engaged with your content is the backbone of a warmup. 

This is true even when you’ve had an email program prior to migrating your data into NationBuilder. Since your sending reputation is based on the combined reputation of your domain and IP address(es), your reputation resets to a degree as soon as you switch email platforms.  


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Pro-tip: only target engaged recipients

The key is to garner as much engagement as possible and avoid recipients flagging your content as spam.

While we’re sure you’re eager to get going as quickly as possible to target the segments you were hitting before, the time it takes to warm yourself up will depend on the engagement of your recipients throughout the process and the receptiveness of ISPs. With that in mind, a typical warmup programme can last a few weeks depending on the size of your database. You’ll want to make sure you target your most engaged recipients in those early stages in order to get stellar engagement rates. After which you will want to pepper in less engaged folks with your most active recipients.

You’ll want to make sure to use content you know your users are going to be eager to engage with, including simple calls to action like signing a petition or answering a survey. While donation asks aren’t totally out of the question in the right context (and crucially to the right folks!), it might be worth considering postponing your fundraising campaign at this stage of the warmup.  

Say you’ve got an emailable database size of 10,000 - you will want to start with less than 10% of that as a source for your most engaged recipients. So your first send will target 500 folks (users who most recently joined your mailing list, who clicked an email in the last 90 days, opened an email in the last 30 days, etc). After which, you will want to double in sends from one day to the next. 

Keep an eye out on your stats 

If your emails aren’t getting opened, being marked as spam or are bouncing, then stop the warm-up programme, talk to your Enterprise Account Manager (if you have one!) and reconsider your email practices. Have you targeted a new segment of folks? What was your ask? Did it differ from previous asks? Did the content of your emails change? Essentially, consider what has been done differently to spark a sudden change in engagement rates.  

With that said, these are the stats you should be aiming for throughout your warmup period (and even after!): 

  • Open rates above 20%
  • Click rates above 2%
  • Bounce rates below 3%
  • Bad rates below 1% 
  • Spam rates below 0.01%

The goal of your warmup is to show ISPs you are in for the long haul and that your recipients have opted-in and want to hear from you, which means putting the necessary time and effort into making sure your emails land in your recipients’ inboxes. Rushing into the process will only trigger alarm bells for ISPs. 

But do not fret, you’ve now got everything you need to start your warmup programme. This may seem like a tedious process, but it will pay off in the long term as you’ll be better able to reach and engage with those capable of helping you achieve your mission and goals!

Madeleine Cazes

Madeleine Cazes

Senior Enterprise Account Manager based in London, UK. Madeleine in French. Maddy in English.

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