Configure Smart Sending on an email broadcast

Email broadcasts now expose Smart Sending through the API. smart_sending turns it on or off, and smart_sending_time (0.5 to 100) with smart_sending_unit (hour or day) size the window a send is spread across. All three are settable on create and while the broadcast is still a draft, and all three come back on read.

The gotcha worth knowing up front: smart_sending defaults to true, so a broadcast you create without mentioning it is delivered gradually rather than all at once. Send smart_sending: false explicitly if you want the whole audience to go in one shot. Above 5,000 recipients Smart Sending is mandatory: false is accepted and may be stored as true, and the send batches at that size regardless of the stored value.

Sizing the window is optional and usually unnecessary. The two window fields read back as null until you set them, which means the window is being sized from the size of your audience instead, the same way the dashboard sizes it. They are one setting in two fields, so send them together or not at all.

Agent examples: create a newsletter broadcast that goes out to everyone at once instead of trickling · spread a large announcement over two hours with smart_sending_time: 2 and smart_sending_unit: "hour".

Resources: Emails::Broadcast
Building with an AI agent? Point it at the Emails skill.