Your site lacks a "robots.txt" file. This file can protect private content from appearing online, save bandwidth, and lower load time on your server. A missing "robots.txt" file also generates additional errors in your apache log whenever robots request one. Read more about the robots.txt file, and how to create one for your site.

Your site lacks a sitemap file. Sitemaps can help robots index your content more thoroughly and quickly. Read more on Google's guidelines for implementing the sitemap protocol.

Your webpage has 58 'img' tags and 40 of them are missing the required 'alt' attribute.

Congratulations! Your page does not use HTML deprecated tags.

Congratulations! There are no severe JavaScript errors on your web page.

Congratulations! Your page is successfully compressed using gzip compression on your code.
Your HTML is compressed from 99.47 Kb to 18.48 Kb (81 % size savings). This helps ensure a faster loading web page and improved user experience.

Your site loading time is around 13.986 seconds and is over the average loading speed which is 5 seconds.

Your page has more than 20 http requests, which can slow down page loading. You can try reducing http requests through various methods such as using text instead of images, using css sprites, using data URIs instead of images, or combining several external files together into one.

Congratulations! Your webpage use 'Expires' header for your images and the browsers will display these images from the cache.

Your URL performed one redirect! While redirects are typically not advisable (as they can affect search engine indexing issues and adversely affect site loading time), one redirect may be acceptable, particularly if the URL is redirecting from a non-www version to its www version, or vice-versa.

http://diff.vn and http://www.diff.vn/ resolve to the same URL.

We found 1 email addresses in your page code. We advise you to protect email links in a way that hides them from the spam harvesters.

Congratulations, your website uses media query technique, which is the base for responsive design functionalities.

Your webpage doesn't take the advantages of HTML Microdata specifications in order to markup structured data. View Google's guide for getting started with microdata.

Your webpage does not use the noindex meta tag. This means that your webpage will be read and indexed by search engines.

Your page is using the canonical link tag. This tag specifies that the URL: http://www.diff.vn is preferred to be used in search results. Please ensure that this specification is correct, as canonical tags are often hard-coded and may not always reflect the latest changes in a site's URL structure.

Your webpage does not use the nofollow meta tag. This means that search engines will crawl all links from your webpage.

Your site lacks a "robots.txt" file. This file can protect private content from appearing online, save bandwidth, and lower load on your server. A missing "robots.txt" file also generates additional errors in your apache log whenever robots request one.

Congratulations! Your DNS server is using an SPF record. This SPF record is listed below: