app/Http/Middleware/GzipMiddleware.php

<?php
namespace App\Http\Middleware;

use Closure;


class GzipMiddleware
{
    /**
     * Handle an incoming request.
     *
     * @param  \Illuminate\Http\Request $request
     * @param  \Closure $next
     * @return mixed
     */
    public function handle($request, Closure $next)
    {
        $response = $next($request);
        $content = $response->content();
        $data = gzencode($content, 9);

        return response($data)->withHeaders([
            'Access-Control-Allow-Origin' => '*',
            'Access-Control-Allow-Methods'=> 'GET',            
            'Content-Length'=> strlen($data),
            'Content-Encoding' => 'gzip'
        ]);
    }
}