Site Speed Basics: Server-Side | Lesson 28/34 | SEMrush Academy

You will get advice on how to optimize your website performance and implement HTTPS and HTTP/2.
Watch the full course for free:

0:14 Performance optimization
0:44 Questions you need to ask and things you need to understand
2:13 Time to First Byte or TTFB
2:53’s Global TTFB Testing tool
3:35 Make sure that caching works well
4:03 Consider pre-fetching and pre-rendering

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Tune up your website’s internal linking with the Site Audit tool:

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Another thing we need to talk about is the backend or server side of things – so essentially your infrastructure. Performance optimization also heavily depends on which systems you are running on, how they are interconnected, etc. For less technical marketers it’s particularly important to understand that optimization should not only be done in the frontend as covered before, but also in the backend. So, you need to get your IT involved as well and make sure they have performance optimization topics on their radar.

Some questions to get you started and things you need to understand:

What webservers are you using, and are they the best fit for what you want to achieve? For example, Apache is totally different from nginx.
What does your database and its structure look like dealing with the queries they have to answer?
Are you running a MySQL database and is that using any type of caching?
Or are you running fully on HTTPS? Then you should enable OSCP Stapling.
Are you sure that you are levering browser caching properly? Have you even considered EDGE caching?
There are so many different things that you can do that really make a difference. But they mostly depend on the setup, which is always somewhat specific to the individual.

If you have a lot of images and other static files consider using a CDN or at least a heavily optimized asset server. An asset server generally should be cookie-less and optimized for delivering statics ASAP – so nginx could be a good starting point. Generally, a CDN like Cloudflare would be a very good approach to offload static files that you have on your application server as well. Having static files on the application server is usually way slower than putting them on the CDN. This also helps with international visitors as CDNs usually distribute from very different points of the world. The latency to your users goes down significantly.

This ties in quite nicely to something called Time to First Byte or TTFB in short. It measures the responsiveness of a web server: the amount of time between creating a connection & downloading the contents of a web page, and sending it back. Google says they are not using it in search rankings per se, but it is still important. If the latency is super high, nothing is going to happen, and people will just leave – because your site doesn’t respond. No chance they will stick around forever – so clearly TTFB does matter.

One of the really cool and free tools is available at They have a global TTFB testing tool, which checks the performance of your site from 14 different locations around the world in one glance. They measure DNS time, TTFB and handshakes. If you look at average numbers and you can manage below 200 milliseconds, that would be good. 500 ms is already too long, 1 second or more is bad.

Optimizing TTFB is something that you, as an SEO, can’t do yourself. It’s usually infrastructure-related or server-related, so go and talk to the IT team if your numbers are bad.

You have to be sure that caching works well. Make sure that you send proper caching headers and that you are leveraging the fact that for the second request most of the images requests, СSS, JS etc will be stored locally in the browser.

A good approach would be to go to and see how well and efficient your caching rules are set up. If any images are not cached for at least a couple of days, then this should be changed sooner rather than later.

Another powerful concept in making sites faster is considering pre-fetch and pre-render. It is especially true if you depend on 3rd party requests or contents. Do you request data from a CDN or a subdomain, for example? You could pre-fetch the DNS lookup to that third party host. Basically in the background, it ensures that the IP address for that host has been resolved already, so when the first request goes out, it goes faster as the browser does not have to wait for the DNS lookup to be executed.

#TechnicalSEO #TechnicalSEOcourse #SiteSpeed #SEMrushAcademy

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