- Craig A West brought CURLOPT_NOPROXY and the corresponding --noproxy option.

They basically offer the same thing the NO_PROXY environment variable only
  offered previously: list a set of host names that shall not use the proxy
  even if one is specified.

docs/MANUAL

@@ -136,6 +136,11 @@ PROXY
 
         curl -U user:passwd -x my-proxy:888 http://www.get.this/
 
+ A comma-separated list of hosts and domains which do not use the proxy can
+ be specified as:
+
+        curl --noproxy localhost,get.this -x my-proxy:888 http://www.get.this/
+
  curl also supports SOCKS4 and SOCKS5 proxies with --socks4 and --socks5.
 
  See also the environment variables Curl support that offer further proxy
@@ -793,8 +798,9 @@ ENVIRONMENT VARIABLES
 
         NO_PROXY
 
-  If a tail substring of the domain-path for a host matches one of these
-  strings, transactions with that node will not be proxied.
+  If the host name matches one of these strings, or the host is within the
+  domain of one of these strings, transactions with that node will not be
+  proxied.
 
 
   The usage of the -x/--proxy flag overrides the environment variables.