Setting up Postmark delivery server


New Member
I have setup a delivery server for "Postmarkapp" using the API route and the API has been confirmed as OK.

Postmarkapp have different "Mailing Streams", 'Broadcast', 'Inbound' & 'Broadcast' the default send stream being 'Transactional'. I have setup a new 'Broadcast' stream and need to be able to direct campaigns through that stream the php direction would be - $messageStream = "mw-broadcast-stream" - is this to be included in 'Additional Headers' in the Delivery Server setup and if so what format please.

Any wisdom in this area would be appreciated, thanks