Preview a broadcast
Renders the email exactly as customer_id would receive it (subject, preview line and the full HTML in the account’s layout) without sending anything. Nothing is recorded: no delivery, no stats, no enrollment. The unsubscribe link in it is a placeholder that unsubscribes nobody. A draft or scheduled broadcast renders from its current content; one that is sending or sent renders from the snapshot that went out. Broadcasts use only live variables, so data_source is customer (or none).
Authorizations
API key in the format: Bearer {api_token}
Headers
Makes this write safe to retry: a repeat with the same key replays the first response instead of creating a second resource. Scoped to the account, remembered for 24 hours; reusing a key with a different payload is an error.
255Path Parameters
The broadcast's prefixed id (e.g. bcst_abc123).
Body
Render as this customer (cus_...). Omit to use every variable's default.
Response
The rendered email
An email rendered for one customer exactly as they would receive it, without sending it.
email_preview The subject with its variables filled in.
The inbox preview line with its variables filled in, or empty.
The whole email, layout included. Its unsubscribe link is a placeholder that unsubscribes nobody.
Whose data filled the variables: none (no customer_id, so every variable uses its default), customer (their details as they are now), enrollment (a sequence step for someone enrolled: what they joined with), latest_order (not enrolled, so product and order variables come from their latest order) or no_order (not enrolled and no order, so those variables are blank).
none, customer, enrollment, latest_order, no_order 
