Render the Slack Block Kit preview
Read-only — the exact render the send pipeline would post. Either `aggregate=1` (the union across every targeted audience, annotated with per-block visibility) or `audience_id` (one audience's exact render) is required; `audience_id` must be an audience actually targeted by this broadcast.
/api/broadcasts/{id}/previewA Stet API key (prefix bk_), created under Settings → API keys. The whole API requires the Growth plan or higher; keys are scoped read or write — composing and sending require write.
In: header
Path Parameters
Query Parameters
Pass 1 for the aggregate multi-audience render.
"1"Required unless aggregate=1.
Response Body
curl -X GET "https://app.stethq.com/api/broadcasts/string/preview?aggregate=1&audience_id=string"{
"blocks": [
{}
]
}{
"type": "http://example.com",
"title": "string",
"status": 0,
"detail": "string",
"instance": "string"
}{
"type": "http://example.com",
"title": "string",
"status": 0,
"detail": "string",
"instance": "string"
}{
"type": "http://example.com",
"title": "string",
"status": 0,
"detail": "string",
"instance": "string"
}{
"type": "http://example.com",
"title": "string",
"status": 0,
"detail": "string",
"instance": "string"
}List per-channel send results
Failed sends first, then pending, then everything else; channel name ascending within each group.
Replace the broadcast's one-time channel group
Requires `write` (`broadcast:compose`). The ONLY write surface for a broadcast's ad-hoc one-time channel group — an empty `channelIds` deletes the group. Draft-only — `409` on any other status.