restclient.el which you can use in Vim!
there is overhead, less than you might think though, around 300ms. Rather than C-cC-c you just run :Restclient. For unformatted response output append -raw, like so: :Restclient -raw
To get the equivalent as a cURL command, use :RestclientCurl , which takes an optional register, and copies.
For installing in the comfort of your shell, just run:
emacs --quick --batch --eval="(progn(require 'package) (package-initialize) (add-to-list 'package-archives '(\"melpa\" . \"http://melpa.milkbox.net/packages/\") t) (setq url-http-attempt-keepalives nil) (package-refresh-contents) (package-install 'restclient))"
For basic syntax highlighting, when editing requests, :set ft=conf. The response gets displayed in vim's internal pager, but this can be changed however, see :h :redir