Send Time Optimization (STO) determines the optimal times during a specified time period to send a campaign. This article outlines Bluecore’s recommended best practices of when and how to use STO with your email marketing strategy.

The below guidelines and recommendations ensure STO is successful with:

  • Deliverability and performance: These recommendations will successfully ensure that the right audience sizes and criteria are being met to best optimize campaigns using STO.

  • Control and test groups: Overlapping send times and audiences can cause STO to send fewer emails than expected, which ultimately impacts the control and test groups. Follow the below recommendations to ensure optimization of the STO model.

  • Optimizing for clicks: STO optimizes for increased campaign click performance. This drives shoppers deeper into the purchase pipeline and increases shopper engagement.


  • Campaigns that are not time-sensitive: Campaigns that express urgency and are time-based shouldn’t use STO. These campaigns are reactionary, and using STO delivers emails based on when they’d be engaged with, so it’s recommended to not use STO on continuous or hourly triggered-based campaigns.

  • Campaigns with overlapping audiences: Bluecore does not recommend setting up STO campaigns that have a large overlapping audience with other STO or non-STO campaigns that will send in the same time frame.

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