Checking in on one of our newest products that makes email easy.

Early in 2019, SparkPost released an Automated IP Warmup feature designed to make adding a new dedicated IP a breeze. We wanted to circle back around and share some of the great results we’ve seen with this product so far. First things first, if you’ve used the Automated IP Warmup feature or are thinking about using it in the future, I’d love to have a quick chat. Feel free to book me for a quick fifteen minutes to learn more or share your story.

Since releasing this feature, we’ve been able to warm hundreds of dedicated IP addresses with great results. As I’m writing this message, some 1,200 IPs are in the warmup process! Some of our customers have used the feature to warm up to just a couple thousand messages a day while others have gone all the way to stage 22 – that’s 1.75 million messages a day through their IP!

The really exciting part is that the deliverability and health metrics of these young IPs are just as good as the IPs that already exist in the pool! That means that we’ve been able to hone in on a good warm up pattern for most dedicated IPs. Whether you’re just getting started with email, growing your volume, adding a new stream, swapping out IPs, or transferring your traffic to SparkPost – we think you’re going to have a great experience!

We’ve gone through and taken a closer look at a couple accounts to see how their IPs are performing. Here are some great examples of a recent set of IPs that have been added and went through the Automated Warmup Process:

Sender A maintains a dedicated IP to alert customers of critical notifications. To add redundancy to their system, this sender added a second dedicated IP to their critical notifications IP Pool. At the time of writing this blog, the newly added IP is in stage 9 of warmup – capable of sending 50,000 emails per day before falling back solely to the warm IP. Here are the results of how the existing IP and the newly added IP are performing within the same pool for the last 25,000 messages:

Accepted % Hard Bounce % Soft Bounce % Block Bounce % Undetermined Bounce % Open %
Existing IP 98.28% 0.91% 0.40% 0.23% 0.19% 82.21%
Newly Added IP 98.33% 0.96% 0.36% 0.20% 0.15% 83.46%


Sender B added two dedicated IPs to an existing pool that previously only had one dedicated IP. Both of these newly added IPs have progressed to stage 8; capable of sending up to a combined 80,000 emails before solely relying on the warm IP. Here’s their performance recently:

Accepted % Hard Bounce % Soft Bounce % Block Bounce % Undetermined Bounce % Open %
Existing IP 99.98% 0.02% 0.01% 0.00% 0.00% 3.76%
1st Newly Added IP 99.97% 0.02% 0.02% 0.00% 0.00% 3.63%
2nd Newly Added IP 99.98% 0.02% 0.00% 0.00% 0.00% 3.97%


As you can see, in both situations the newly added IPs are performing just as well as the other IPs in the pool. This is great news and we’re thrilled to share these results.

Even though we’re excited about the results we’re seeing, we’re not done yet. Our goal is to continue to make email easy for our customers. Keep an eye out in the coming months for more posts and continued updates for our Automated IP Warmup product.

Happy Sending,
Harold and Balu