I think this is where Delimited Dynamic binding would come in to play: https://okmij.org/ftp/papers/DDBinding.pdf

I think that you would be able to freeze certain variables in the closure, and have others open eg. API_ENDPOINT variable might be configured to change between environments.

Something like https://github.com/GiacomoCau/wat-js implements delimited continuations, ddbinding and algebraic effects (registered handlers for I/O etc) - pushing continuations over the network should be easier with these facilities.