Node.js version of urltools es more fast (53% aprox), you can try this with strace -o trace -c -Ttt

plugins/urltools/urltools.plugin.zsh

@@ -4,6 +4,6 @@
 # Taken from:
 # http://ruslanspivak.com/2010/06/02/urlencode-and-urldecode-from-a-command-line/
 
-alias urlencode='python -c "import sys, urllib as ul; print ul.quote_plus(sys.argv[1])"'
+alias urlencode='node -e "console.log(encodeURIComponent(process.argv[1]))"'
 
-alias urldecode='python -c "import sys, urllib as ul; print ul.unquote_plus(sys.argv[1])"'
+alias urldecode='node -e "console.log(decodeURIComponent(process.argv[1]))"'