fixed urls on polymer

I'm working with polymer and I'm testing all in my local environment and all is working as expected, but the problem is when I'll move it into production, where the url shouldn't be the same as in my local. In node.js I can set it via the config.json file and catch it with app.get('config') or something like that, but in polymer I cant get it, and the only chance I have is to create another endpoint with all the config.json config file, but, and here is the best part, I should hardcode this url in polymer!! (so annoying). There is some way or library or component or something that I'm missing ?

Thanks in advance guys! StackOverflow and the users helped my a lot!

UPDATE

The thing is that I'm using custom elements (because I had handlebars too and there is a little problem with the {{}}) so, in the custom elements that I created I have this (for example in the core-ajax call):

<core-ajax id="login" auto="false" method="POST" contentType="application/json" url="/app/middle/login" ....></core-ajax>

as you can see the url is a little bit hardcoded, I want to use something like this (this is what I have on the node.js endpoint application):

router.post(endpoint.login, function (req, res) {

and I want to got something like that over polymer

<core-ajax id="login" auto="false" method="POST" contentType="application/json" url="{{login}}" ... ></core-ajax>

<script>
Polymer('log-form', {
 login: endpoint.login,

  ready: function () { 
  ....
  })
});
</script>

I'ts more clear now? I'm not so strong on english language.

Thanks Guys, for all!