Send to Open Time

Send to Open Time

Dec 13, 2021

Ian Morton

Back to all posts

Over the last few Nerd Voice articles, we have discussed the importance of accurate data for decision-making. This week we wanted to delve into one of the tools we use to analyze patterns in email data, send to open time. This has become an increasingly important measurement over the last few months since Apple’s MPP rollout. Below is a graph of a sample of opens from Apple Mail clients with iCloud private relay opens removed. Opens are highest a few minutes after the message is sent. 

If a sender can identify when a recipient is in their mailbox, they can maximize the chance that their message will be interacted with. “Above the Fold” is as old as marketing itself. Google has an entire section of AdWords dedicated to positioning your message at the very top of the inbox. This is also the foundation of send time optimization, identifying when a recipient is most likely to be in their inbox to maximize engagement. Because of Apple’s Mobile Privacy Protection (MPP) and other auto-opener technologies, this assertion becomes much muddier. 

After iOS 15 launched Apple mail opens spiked significantly. Based on the S2O timings, our team was able to identify patterns from those open events to track IP ranges that are being used by ICloud Private Relay and others.

Auto openers are not new. They have become increasingly common amongst larger mailbox providers, not just Apple. Send to Open time analysis has allowed AudiencePoint to ensure we are able to provide accurate information to our customers about when a subscriber is in their inbox while allowing us to filter out bad opens.