Don’t just make assumptions about when your customers are most likely to open their email; use send time optimization (STO) to learn your customer’s behavior and deliver email at the best time, when they are most likely to open it.
How it works
Campaign collects and stores information to determine the time that each contact most commonly opens their email. For example, if Jane Doe opens most emails at 3 p.m. but her most recent open occurred at 10 p.m., her optimized send time remains 3 p.m. STO continually calculates the most likely time of open, so if Jane’s interaction with your emails change over time, her send time will change, as well.
The optimal time for sending a user email is stored as a send hour value. The send hour ranges from 0 to 168, representing each hour from Sunday 12:00 midnight GMT through Saturday 11:00 PM GMT. A send hour of 0 means that mail will be sent immediately. When you add a new contact or enable a new database, the send hour field is automatically set to 0. The hour value will change as information about the user is collected. For a complete list of the values, refer to Send hour values.
STO can be enable at send time for single email sends or for program steps that send email. For details specific to program emails that use STO, refer to Use STO for program emails.
Enable STO on a database
Any single or double opt-in database can be enabled for send time optimization. To enable a database:
- Add a send hour type field to your database.
- Go to the database summary page.
- Click Settings.
- Click the checkbox to enable the send time optimization setting.
- Save the database settings.
Once a database is enabled, you will see Send Time Optimization: Enabled on the summary page. Campaign will then collect the open data for the previous 30 days of email and currents sends to identify the optimal delivery time for each contact. The time required to collect the data varies according to the size of the database.
Users cannot delete the Send Hour field in their Acoustic Campaign database. This safety mechanism is designed to prevent unintentional overwriting of values in Send Hour fields.
24-hour and 7-day send types
The send hour can be calculated over a span of 24 hours or over 7 days. The 7-day option is not available for email steps that are part of a program. An STO send that spans 24 hours begins sending at the first whole hour that occurs after processing completes. It continues to send every hour on the hour for the next 24 hours. Because send hour values represent each hour within a week, conversion is required for a 24-hour send. An STO send that spans 7 days does not require conversion.
For a 7-day STO send, a contact with a send hour that equates to Monday at 7 p.m. is sent to on Mondays at 7 p.m. For a 24-hour STO send, that same contact has email delivered at 7 p.m., regardless of the day of the week the send is scheduled for or triggered in.
- On Tuesday at 2 p.m., you schedule a send for Thursday at 3:30 p.m. with 24-hour send time optimization selected.
- Sending begins on Thursday at 3:30 p.m. for all contacts with a send hour of 0.
- The next send begins at 4 p.m. for contacts with a send hour that is the equivalent of 4 p.m., regardless of the day of the week.
- The next send begins at 5 p.m. and continues around the clock until the last send takes place at 3 p.m. the following day.
- On Thursday, May 21 at 1 p.m., you schedule a send for Thursday, May 21 at 2 p.m. with 7-day STO option selected.
- All contacts with a send hour of 0 AND all contacts of a send hour that matches Thursday at 2 p.m. begin sending on Thursday, May 21 at 2 p.m.
- The next send begins on Thursday, May 21 at 5 p.m., for contacts with a send hour that matches Thursday at 5 p.m. This continues throughout the week, with the last send taking place on Thursday, May 28 at 3 p.m. for the last group of contacts.
The majority of marketers have databases comprised of contacts across a number of time zones. Because messages sent with send time optimization are delivered based on the contact's past email activity, you can send a message once and regardless of time zone, your message is delivered at the most optimal time. International emails have never been easier!
Considerations when using STO
STO processing during IP warming
When Acoustic Campaign sends an email, the contact source is first evaluated to determine whether sending to all of the addresses breach the daily IP warming limit for any of the warming domains.
You should not use STO during the IP warming process.
Changing STO values after an email is sent
When an email is sent with Send Time Optimization enabled, the email processes all of the contacts in the list and pulls in the STO time that is associated with that contact. Updating values for a contact after the email is sent does not change the STO for that contact on the email.
STO and throttling
Send time optimization and throttling are not compatible. If you have both enabled, STO will override throttling to send email at the optimized time regardless of how many emails have been sent.
STO email remains in sending status
This status is normal behavior for STO email. STO email remain as sending until the email is sent to all recipients based on the value in their send hour field. Upon completion, the email status will be changed to sent.