[Vuejs]-Using browser-sync with vue js and framework7

Based on your comment, looks like you are also using webpack-dev-server. In that case you can proxy to it:

const BrowserSyncPlugin = require('browser-sync-webpack-plugin')

module.exports = {
  // ...

  devServer: {
    port: 3100
  }

  // ...

  plugins: [
    new BrowserSyncPlugin(
      // BrowserSync options
      {
        // browse to http://localhost:3000/ during development
        host: 'localhost',
        port: 3000,
        // proxy the Webpack Dev Server endpoint
        // (which should be serving on http://localhost:3100/)
        // through BrowserSync
        proxy: 'http://localhost:3100/'
      },
      // plugin options
      {
        // prevent BrowserSync from reloading the page
        // and let Webpack Dev Server take care of this
        reload: false
      }
    )
  ]
}