curl --request POST \
  --url https://api.lithoblocks.com/templates/{id}/send \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "data": {},
  "channelId": "<string>",
  "recipientEmail": "[email protected]",
  "recipientSlackId": "<string>"
}
'

{
  "success": true,
  "message_ts": "<string>",
  "channel": "<string>",
  "remaining_credits": 123
}