For those who are trying it on postman ~ 7.10.0, you can add headers programmatically in a pre-request script, into the request or into the collection (into collection will add headers to all requests inside collection).
pm.request.headers.add({
// These keys appears when you set a header by hand. Just for fun they are here
disabled: false,
description:{
content: "DescriptionTest",
type: "text/plain"
},
// Your header, effectively
key: 'KeyTest',
name: 'NameTest',
// If you set a variable you can access it
// HeaderTest here has value="ValueHeaderTest"
value: pm.collectionVariables.get("HeaderTest")
});
The code snippet generator will not show the added header:
GET /get_info.php HTTP/1.1
Host: 192.168.15.25:8001
Content-type: application/json
User-Agent: PostmanRuntime/7.19.0
Accept: */*
Host: 192.168.15.25:8001
Accept-Encoding: gzip, deflate
Connection: keep-alive
But the Postman Console will:
GET /get_info.php HTTP/1.1
Content-type: application/json
KeyTest: ValueHeaderTest
User-Agent: PostmanRuntime/7.19.0
Accept: */*
Host: 192.168.15.25:8001
Accept-Encoding: gzip, deflate
Connection: keep-alive