[Exist-open] http request read environment variable

[Roy W. <gar...@ya...>]

I had a working SendGrid implementation using httpclient:post where  an API key was sent as header.
Having upgraded to 5.x, httpclient is no longer available so I am using http:send-request. My SendGrid implementation no longer works because the API key is sent as if from a browser, which is perceived at SendGrid's end as a security risk.
The recommendation is to store the API key in an environment variable. I have no idea how or whether this can be achieved in eXist.
Does anyone have any insight on this?
Thanks as ever,Roy