CORS issue with Vue.js

You face this error when the API url and client url aren't the same. Vue CLI 3 (and in the core of it, Webpack) allows you to proxy your API url to your client url.

Inside vue.config.js file add following lines:

// vue.config.jsmodule.exports = {  // options...  devServer: {        proxy: 'https://mywebsite/',    }}

And then send your ajax calls to http://localhost/api/.

You can read the full article here:How to deal with CORS error on Vue CLI 3?

While you can add Access-Control-Allow-Origin: * to your server response (in this case IIS) but this is very much advised against.

What's happening here is that your client is http://localhost and it is trying to access https://mywebsite/api/ which means they're not from the same origin

If you add Access-Control-Allow-Origin: * you will be allowing the entire world to hit your API endpoint.

I'd suggest making your access control server headers Access-Control-Allow-Origin: *.mysite and make a vhost for your localhost to use dev.mysite or similar.

This will allow your "localhost" to access your API without issues.

You could also add localhost to a whitelist, but this is also not without its own security implications, and it doesn't work everywhere anyway.

So, in short, make a vhost for your localhost that's in the same domain as your REST service and your issue should be resolved.

Once you go live you should remove the *.mysite part and use as specific a domain as possible on your whitelist.

Good luck!

1) Be sure that server sends Access-Control-Allow-Origin "*" header.

2) Vue.http.headers.common['Access-Control-Allow-Origin'] = true, Vue.http.headers.common['Access-Control-Allow-Origin'] = '*' and etc. don't needed in the client request.

3) Vue.http.options.emulateJSON = true should helps if 1 and 2 points already are ok, but vue-resource fails with status 0. Also, try to remove (if they exist) Vue.http.options.credentials = true andVue.http.options.emulateHTTP = true.