My GruntFile.js setup for BrowserSync. I turn off ghost mode for independent play on various devices. Also since I had issues with iPhone connecting to my server I added a named tunnel.

My BrowserSync Gruntfile Settings

browserSync: {
    dev: {
        bsFiles: {
            src : 'style.css'
        },
        options: {
            proxy: "local.testing.dev",
            ghostmode: false,
            port: 8080,
            tunnel: "testing", // < Used for iPhone testing
            watchTask: true // < VERY important
        }
    }
}
        
//The "end" of my gruntfile config looks like this
grunt.loadNpmTasks('grunt-browser-sync');

// register task - Note you HAVE to add browserSync before watch
grunt.registerTask('default', ['browserSync', 'sass', 'uglify', 'imagemin', 'autoprefixer','watch']);