Anyone that has used the internet has been frustrated by slow load times for websites. This can vary from simple annoyance to completely abandoning the site due to how slow it is to load and use. While certain things like the speed of light or bad cell connections is outside of the control of mere mortals, there is many things that can you can to ensure that your website is loading quickly for your users. In this paper we will be going through different things that will affect your website load times, how to test them, and what you can do to fix these.
To start this discussion we will need to look at different ways that you can measure the performance of your website. There is many different moving parts to a complex website and there is also many different ways to go about testing a site. For the purposes of this paper we are going to focus on some simple ways that are also universally applicable. I will be doing these tests from Ubuntu but any *nix os or Windows subsystem for linux will have very similar tools and outputs.
First the way that pretty much anyone that started in to technology will learn Ping. Ping is a simple utility that leverages the ICMP protocol to get a simple response from the destination. This can be used to measure the round trip time of a single packet. This simplicity is its strength as well as its weakness. But lets look at a easy example:
> ping www.invoke.coffee PING www.invoke.coffee (126.96.36.199) 56(84) bytes of data. 64 bytes from 188.8.131.52 (184.108.40.206): icmp_seq=1 ttl=51 time=45.4 ms 64 bytes from 220.127.116.11 (18.104.22.168): icmp_seq=2 ttl=51 time=46.4 ms 64 bytes from 22.214.171.124 (126.96.36.199): icmp_seq=3 ttl=51 time=39.10 ms
The means that from my home it will take a minimum of 45ms to get to this webserver and back. This only measures the network latency and some websites will block ICMP. Lower this is for your user faster the page will load.
The next test we will use is curl. Curl is a command line HTTP client that is perfect for getting the time to download a single page. We can use this with time to measure how long it will take to transfer a single file.
>time curl -I https://www.invoke.coffee HTTP/1.1 200 OK Server: nginx/1.15.5 (Ubuntu) Date: Mon, 25 Feb 2019 03:17:11 GMT Content-Type: text/html Content-Length: 7680 Last-Modified: Wed, 26 Dec 2018 03:17:31 GMT Connection: keep-alive ETag: "5c22f2cb-1e00" Accept-Ranges: bytes real 0m0.190s user 0m0.004s sys 0m0.012s
In this example it will take .19 seconds to load the base page of this site. You can also use this to understand the download time for other assets like images and CSS.
The first thing to discuss is something that I touched on in the intro. While today's high speed internet connections are extremely fast and getting faster. We will never be able to overcome the simple fact that distance is a factor in how quickly you can download a web page. As you are building a website you need to think about where your primary users are going to be. If it is going to be a website for a physical store or extremely local this will be very specific. But even if you are building a totally online presence you will still be targeting some user base. A simple example is that if your website is in english your user base will be primarily from english speaking countries. As you are looking at hosting providers you should look up where there data centers are located. Most will not specify a physical address but will give you a general location. Digital Ocean for example has data centers is several locations like San Francisco New York or London . Choosing to physically locate your hosting provider to your users is an easy win.
Cache-Control: max-age=<seconds> header is the most important one. This tells the CDN how long to cache the content before going back to your website to check for updated content. You will also want to ensure that you are NOT caching any dynamic content a good example of this is a login page. If you have a user login then that page is cached the next user would get the first users logon page. Using curl you can check that your website is returning this header.
You can test if your web server accepts streaming compression with curl. For example we can check https://www.invoke.coffee and see that if we specify
> curl https://www.invoke.coffee -I -H "Accept-Encoding: gzip" HTTP/1.1 200 OK Server: nginx/1.15.5 (Ubuntu) Date: Mon, 25 Feb 2019 01:32:42 GMT Content-Type: text/html Last-Modified: Wed, 26 Dec 2018 03:17:31 GMT Connection: keep-alive ETag: W/"5c22f2cb-1e00" Content-Encoding: gzip
The web server will return the content compressed with gzip.
But if we go to https://www.highline.edu/ it does not accept gzip.
> curl https://www.highline.edu/ -I -H "Accept-Encoding: gzip" HTTP/1.1 200 OK Date: Mon, 25 Feb 2019 01:36:16 GMT Server: Apache/2.4.7 (Ubuntu) X-Powered-By: W3 Total Cache/0.9.5.4 X-Pingback: https://www.highline.edu/xmlrpc.php Link: <https://www.highline.edu/wp-json/>; rel="https://api.w.org/" Link: <https://www.highline.edu/>; rel=shortlink X-TEC-API-VERSION: v1 X-TEC-API-ROOT: https://www.highline.edu/wp-json/tribe/events/v1/ X-TEC-API-ORIGIN: https://www.highline.edu Cache-Control: max-age=3600 Expires: Mon, 25 Feb 2019 02:36:16 GMT Content-Type: text/html; charset=UTF-8
The number and size of the assets that the browsers have to download do matter. This is especially true when the client has a slow internet connection. A good example of this is images. They can be gigabytes in size and this would drastically affect the load speed of your website. For images you will want to compress them using something like the Joint Photographic Experts Group (jpeg) format. This is a lossy image compression format that can drastically reduce the size of the image. This can also compress so far that the image is totally lost. You will need to consider how much compression makes sense for our website and choose accordingly. Using the same curl commands before you can see how much of a difference it will be to reduce the size of these images. But don’t go to far and loose clarity.
There is many things that make up a web sites page load time and there is also many techniques to improve web performance. A good web developer will keep these techniques in mind and also monitor the performance of there website to ensure that there users have having a good experience.