Proxy in package.json not affecting fetch request

You can modify your fetch request API url to give the complete hostname since

 fetch('http://localhost:3000/api/users') 

also make sure that you have CORS enabled on your backend

In case your want to redirect through webpack, your can try devServer.proxy as

devServer: { 
    inline: true, 
    contentBase: './dist', 
    port: 3001, 
    proxy: { "/api/**": { target: 'http://localhost:3000', secure: false }  }
 }