gistfile1.txt

    location ^~ /myapp/ {
        proxy_pass http://0.0.0.0:3001/;
        proxy_http_version 1.1;
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection 'upgrade';
        proxy_set_header Host $host;
        proxy_cache_bypass $http_upgrade;
    }

razzle.config.js

'use strict';

module.exports = {
  modify(config, { target, dev }, webpack) {
    const appConfig = config; // stay immutable here

    if (target === 'web' && dev) {
      appConfig.devServer.public = "razzle.syntapse.co.uk:80";
      appConfig.devServer.proxy = {
        context: () => true,
        target: 'http://localhost:3000'
      };
      appConfig.devServer.index = '';
    }

    return appConfig;
  },
};