Check out CORS your dev environment for Node.js and React.js by David Starr. Here is an excerpt:
Building a Node.js and React.js full stack app can have its tooling annoyances, one of which is getting the Node.js server to allow your requests in from your webpack-dev-server hosted React app, which is going to be running on a different port than your Node application. There are many ways to…
The full article is available here.