Why is my website slow?
Usually images that were never resized, third-party scripts, and a server doing work on every request. In that order. Most slow business websites are slow for reasons that are visible in a browser developer panel within about two minutes.
The longer version
Images are the most common cause and the easiest to fix. A photograph straight from a camera or a stock library can be several megabytes, and a page with six of them is asking a visitor on a phone to download more than the rest of the page combined.
Third-party scripts are the second. Every tag manager, chat widget, analytics tool and embedded map is a request to another company, and your page waits on their server. This is also why a site can be fast on your office connection and slow for a customer.
The third is the server itself. A site that builds every page on request, querying a database each time, is doing work that could have been done once. It also means traffic makes it slower, which is the opposite of what you want during a campaign.
What to do
- Open the network panel in a browser and sort by size. The largest items are almost always images.
- Resize and convert images to a modern format, and serve smaller versions to smaller screens.
- List every third party the page contacts, and remove the ones nobody uses.
- Measure with field data from real visits rather than a single laboratory score, because that is what search engines use.