What does Einstein Send Time Optimization do?

STO uses AI to send each individual contact at their personal best-engagement time, instead of using a single fixed send time.

When is STO most useful?

STO helps most with non-time-sensitive content where personalized timing produces better open rates than a fixed time would.

What does STO need to make accurate predictions?

Like other ML features, STO works best with sufficient historical data per contact to learn engagement patterns.

Einstein Send Time Optimization

AI🟢 Beginner

Definition

A Marketing Cloud feature that uses AI to determine the optimal time to send emails to each individual contact based on their historical engagement patterns, maximizing open rates.

Real-World Example

an AI specialist at Nexus Innovations recently implemented Einstein Send Time Optimization to bring intelligent automation to a process that previously required significant manual effort. Einstein Send Time Optimization analyzes patterns in the data and surfaces insights that would take a human analyst hours to uncover, enabling the team to act proactively rather than reactively.

Why Einstein Send Time Optimization Matters

Einstein Send Time Optimization (STO) is a Marketing Cloud feature that uses AI to determine the optimal send time for each individual contact based on their historical engagement patterns. Instead of sending an entire campaign at a single fixed time, STO staggers the sends so each contact receives the email at their personal best-engagement time. The model looks at when each contact has historically opened and clicked emails and predicts when they're most likely to engage with the next one.

STO is one of the simpler ML applications in Marketing Cloud but can produce meaningful lift in engagement metrics. The benefit is largest for non-time-sensitive content where the exact send time doesn't matter to the merchant. For time-sensitive content (flash sales, breaking news), a uniform send time may still be appropriate. STO works best with substantial historical engagement data per contact, so newer contacts default to a baseline send time until enough data accumulates.

How Organizations Use Einstein Send Time Optimization

•Apex Analytics — Enabled STO for their weekly newsletter sends and saw open rates improve 12% over their previous fixed-time sends.
•MarketPulse — Uses STO for content campaigns but keeps a fixed send time for time-sensitive flash sales where reaching everyone simultaneously matters.
•SilverLine Corp — Combined STO with Engagement Scoring so highly-engaged contacts receive optimized send times while contacts with insufficient history get a default.