Silent Hours, also called quiet hours or Do Not Disturb (DND) hours, prevent messages from being delivered during a selected period.
Availability, configuration, timezone handling, and what happens to affected messages differ by channel and campaign type.
Available in Architect Email channel as an exclusion window when Send Time Optimization (STO) is enabled on the Email element.
Configuration: Open the Email element, enable STO, and select the Silent Hours start and end times.
Time zone: Uses the customer account’s configured time zone.
Behavior: STO selects an eligible send time outside the excluded hours.
The Silent Hours control is in the Launch step of Trigger and Cart Reminder WhatsApp campaigns, and in Architect WhatsApp through STO.
Configuration: For Trigger and Cart Reminder campaigns, enable Silent Hours and select the start and end times in Launch. For Architect, configure the hours in the element’s STO settings.
Time zone: The configuration displays the customer time zone. Architect uses the customer account’s configured time zone.
Behavior: For Architect STO, the system selects an eligible time outside the excluded hours.
Available for eligible SMS senders. It is unavailable for RCS senders.
Configuration: Configure Silent Hours for the sender under SMS settings. Campaigns then follow the configured Silent Hours behavior.
Time zone: Evaluated according to each recipient’s local time zone.
Eligible US senders can enable state-level Silent Hours compliance.
Available in standalone App Push campaigns. An exclusion window is also available through STO.
Configuration: Set the Silent Hours range in the Launch step.
Time zone: Uses the user’s time zone.
Behavior: If a notification is not sent because it falls within Silent Hours, it cannot be sent again.
Available for Trigger, Cart Reminder, Back in Stock, and Price Drop campaigns. Silent Hours are available through STO.
Configuration: Set the restricted period in the Launch step.
Behavior: You can choose to delay delivery until Silent Hours end, or skip the message entirely, when configuring the campaign's Launch step.