Getting Started with Smart Send Time

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Smart Send Time allows you to further understand your customers by using your business' data to see the optimal time for you to email your customers, maximizing open and click rates.

Please note that this feature will only be available on campaigns with recipient counts of 12,000 people or greater.

How Klaviyo's Send Time Optimization Model Is Different

While there are a lot of companies who have send time optimization capabilities, Klaviyo's model is different. Instead of determining your business' send time through hidden formulas, Klaviyo uses a robust testing framework to gather data about your customers to figure out when they are most likely to open your emails. Then, for transparency, your results will always be available to you.

When You Should Use Smart Send Time

While knowing when is best to send is important, it's crucial that you use this feature at the right time. Because we send in recipient local time with Smart Send Time, it’s important to avoid sending time-sensitive content such as a flash sale or an announcement about an impending deadline. Accordingly, you shouldn't do Smart Send Time testing around major holidays or dates that are important to your brand.

How to Utilize Smart Send Time

Exploratory Send

During this phase, Klaviyo will send out an email over a 24-hour period. Customers will be randomly assigned to a time during that period. All emails will be sent in the recipient local time. For instance, if someone is assigned to receive a 10 a.m. email, they will receive it at 10 in their local time.

The email that you send out should be a wide-reaching, not time-sensitive email (e.g., a weekly newsletter). Additionally, you'll want to consider turning off smart sending while using Smart Send Time to ensure that the same people on your list all have an opportunity to open your emails. If you're sending out other campaigns in a similar window, consider sending the non-Smart Send Time email campaign with smart sending or on a different day.

To utilize this feature, create a campaign as you normally would. When you've selected Schedule or Send, in the dropdown under schedule, select the Exploratory (Spread over 24 hours) option in the Smart Send Time category and select Schedule.


In order to narrow down the window of time that works best, the model will need a good amount of data. Depending on how large your usual recipient count is, you may have to do this portion of Smart Send Time multiple times.

Number of Recipients 

Number of Exploratory
Sends Required

<12,000 Not eligible
12,000 - 17,999 4-5
18,000 - 23,999 3-4
24,000 - 47,999 2-3
48,000 - 71,999 1-2
>72,000 1

If you run an exploratory send but the results are skewed (perhaps due to a holiday or, on the other hand, bad timing), you can request that your history Smart Send Time data be deleted. Note that you need to contact Klaviyo Support, and this action will delete all of your Smart Send Time, resetting to before the first exploratory send. 

Focused Send

After the exploratory send phase, Klaviyo will find an optimal send time that has the highest engagement. During the second phase, Klaviyo will continue to validate the time determined from the results of the exploratory send and refine customer behavior changes. During a focused send, one email will send at the optimal send time and two emails will send at in a two-hour window from the optimal send time -- all emails will also send in the recipient's local time. For instance, if the model thinks that 7 a.m. is your optimal send time, your recipients will be split into thirds, and there will be a send that also goes out at 5 a.m. and 9 a.m. in the recipient's local time.

Note that once a focused send time is established, you cannot perform another exploratory send.

In order to send out a focused send email, build your campaign as you normally would. When you've selected Schedule or Send, in the dropdown under schedule, select the Focused send option in the Smart Send Time category and select Schedule.


Smart Send Time Reporting

To see the results of your exploratory or focused sends, click on the campaign where you want to view your metric.


You can see metrics of how each email campaign performed, depending on the time that it was sent, as well as the associated click and conversion rates.

Smart Send Time FAQs

I've been sending to 12,000 recipients and have done the exploratory send 5 times, but still do not see the option for the focused send. Why is that?

For each campaign sent, Klaviyo automatically tracks conversions or a recipient opening an email and then taking another action (such as placing an order) within the conversion period. The send time model waits until after your conversion period before recording the results that will impact your ideal send time. By default, the conversion period is 5 days, but you can change this window in your account settings. For more information, check out our article on Conversion Tracking.

Do I have to use the same list every time I do an exploratory send?

No, you can use different lists. If you're trying to find an optimal send time for a particular group (i.e. just your US customers), you wouldn't want to add in other groups of people, as they would skew the results. However, if you're trying to understand the optimal send time for your entire customer base, you can include all of your lists and segments.

Can I send more than one email using Smart Send Time out at a time?

Yes, you can send out as many as you want. You should still send in accordance with your normal sending cadence. For example, if you normally send emails once a week, you won't want to increase your sending cadence just to have the model work faster. This will skew your results.

Can I A/B test emails while using Smart Send Time?

You should only test one variable at a time. Accordingly, you cannot A/B test Smart Send Time emails.

How many focused sends do I have to send out before I know my true optimal send time?

After the model has enough data to allow you to send out focused emails, it is certain that the time suggested is your optimal send time. The focused send is used to continue to validate and refine the time should your customer behavior change.

How is Smart Send Time different than Smart Sending?

Smart Send Time is a series of tests that allow you to know the optimal time to send to your customers. Smart Send keeps you from bombarding your customers with too many emails over a short period of time. More information about Smart Sending can be found in our Smart Sending for Campaigns article.

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