Core Web Vitals are parameters that measure how quickly a website loads. In 2025, nobody wants to wait 30 seconds for a website to load before the content is readable. Three key figures are central to this:
Vital 1: Completely filled screen
Google recommends that website operators ensure that the website is filled with the first (top) content in under 2.5 seconds. The user usually reads the text at the top first or looks at the images above and then scrolls down. The first section of text/images should therefore be prioritised. While the user reads at the top, the rest can “comfortably” reload.
Vital 2: Reaching the first bytes
Before a website starts loading, your browser must find the website server behind the domain. The Domain Name System (DNS) translates a domain https://lippke.li to an IP address 192.168.178.1.
Every public server has such a number. When the server receives the request, it usually has to search for the content in its memory itself. Finally, the server sends the first bytes to the browser. This process should take less than 100 milliseconds because the page loading only comes afterwards.
IPv6 and HTTP/3 everything done correctly
Vital 3: Time until the final element arrangement
Some websites load in such a way that one element moves other elements during loading, e.g. the text is already loaded, but the header image is not. 1 second later, the header image appears and moves the text down so that the browser only displays the image in the correct size later. No user wants to read a text that is suddenly shifted on the screen.
Why is page speed important?
1. Loading times are annoying
Do you know anyone on this planet who likes to stare at a white screen for 30 seconds? I don’t belong to this rare breed.
Steffen Lippke
Websites have to load quickly to make surfing fun. Even if the content is complex and extensive, the user should see a “loading status” and initial content.
Every second counts
2. Loading time costs revenue
Imagine you need to order coffee online quickly.
You use a search engine and type in “buy coffee”. You click on the first link, but all you see is a white screen.
After 5.4 seconds, you click on the back button and click on the second link. The webshop loads almost instantly (0.8 seconds) and you find your coffee quickly. Webshop 1 with its 16.3 seconds loading time has a massive disadvantage for impatient new customers. Every second of loading time costs you massive sales!
3. Higher load on the server
For some websites, the server has to do a lot of preparatory work and generate the content in the first step. The server can save itself this work if the main memory caches the content for the 1000 most frequent requests.
Main memory is now so cheap that the server can handle many requests without numerical acrobatics. This saves a lot of computing capacity. The server can process several requests per second and is less likely to run out of breath during performance peaks.
My top tips for more speed
#1 Keep it simple, stupid!
Do you really need the thousands of plugins, plugins and functions? Over the years, a lot of rubbish can accumulate on a website, which slows down the system.
Either you go the radical route and completely rebuild the website and only install the essentials… or you deactivate an unnecessary plugin week by week and see what happens.
#2 Compression on!
Gzip and HTTP/3 (or 2) give your website more speed. The less raw data has to be transmitted, the less loading time the tool measures. Lose a lot of size with HTML compression or JavaScript obfuscation.
Top first! Always load content that is at the top of the website first. You can reload large scripts with async and defer. These are important for the interaction later on.
#3 Images compressed and in a new look!
To begin with, you should cut the images to the correct size. A 6000 x 6000 pixel image should not be a 2 cm x 2 cm preview image on the monitor.
Depending on the situation, the browser should load the right image size and resolution. There are dramatic differences in file size between the RAW and JPEG-2000 formats.
Correct size for the images
Raw file formats save separately pixel by pixel, while JPEG combines similar pixels. Don’t overdo the compression because some formats cause a loss of detail.
#4 Fonts locally!
Ideally, you should use the operating system fonts and not your own fonts. All major operating systems have serif and sans-serif fonts, which are easy to read.
If you do fall in love with a font, you should choose a font with a small and optimised file size. In addition, a font should always be reloaded because it is usually only available seconds after the text.
#5 Caching, caching, caching!
You should cache content at every level.
Databases can hold standard queries and web servers can cache entire websites.
A web server with a good cache only needs to move the data from the main memory to the network card.
#6 Correct configs!
The settings on the web server have a massive influence on the speed of the website. Only use the latest PHP, Go or Node version and observe all best practices prescribed by your software / framework.
Every software product has one or more Achilles’ heels which, if set incorrectly, will turn the server into a snail.
#7 Distributed worldwide!
A content delivery network keeps copies of your websites and multimedia content available on many servers worldwide. Instead of requesting the origin server, the user’s browser requests a server that provides the CDN nearby.
The IP packets travel through the cable at the speed of light, but the many intermediate stations (switch, router, …) always require a certain amount of processing time.
What is done well?
#8 More muscle power!
If you have implemented all the measures above, but the website is still terribly slow, you need to use better software and hardware. Depending on the type of website, Apache makes more sense (shared environment), while NGINX is ideal for small files.
The operators of a large website should consider load balancing, virtualising web servers, creating firewalls and black holes that can handle the flow of requests.
Security and speed
A fast website has security advantages. In the event of a (natural) load peak, the server with the “lean” website can still display the content, while an old “fully built” website brings the server to its knees after a few requests.
A lean website reduces the attacker’s paths because there is less attack surface available. Old extensions and components make a website insecure.
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