Has Service Worker usage increased on this website over the past four years?

I think Service Workers are pretty cool. They enable us to do so many powerful things with the web today such as intercepting network requests, caching and retrieving resources and delivering push messages to name a few. In fact, I've been running a Service Worker file on this website for around the past four years.

A few years ago, I wrote an article that showed how to determine the Service Worker usage and support for the users that visited your site by pushing statistics to Google Analytics.  It also went a step further and determined if the users were being served cached data through the supported service worker.

It's been almost four years since I started collecting data and I wanted to look back over time and see if there has been any change to the numbers. Let's first start with the overall number - the chart below represents the percentage of users that visit this website that have browsers that support Service Workers. This number includes desktop and all devices (mobiles, tablets).

From the chart above, you can see that between 2019 and 2021 the percentage of users has remained relatively consistent. The numbers for 2022 have jumped considerably, but it's worth pointing out that at the time of writing this article, we are only 3 months into this year. I expect that this number will flatten out over time.

If you click on the second tab in the chart above, you'll notice the number of "controlled" users to the site. In this case it means how many pages were actually controlled by an active service worker. For example, if someone visits a site with a service worker on it, it will get installed the first time and only used the next time they reload the page or navigate away. I wanted to determine how many people were both supported and using my service worker.

You can see from these numbers that over the years it has remained pretty stable around the 25% mark.

As I looked at the data over time, it was clear that the desktop usage has remained pretty stable with very little growth. I wanted to dive a little more into the mobile phone usage on this site and the chart below represents these numbers.

As you can see from the chart above, the number of mobile devices that visit this site that support Service Workers has remained pretty stable. There doesn't seem like much of a story to tell here. While 2022 looks like it has increased a bit, at the time of writing this article, we are only 3 months into this year. I expect these numbers to flatten out.

Of all the data that I managed to collect, I only started to notice a trend when it came to iPhones. The chart below shows the percentage of iPhone users that visited this site that were both supported (and controlled) by a Service Worker.

Apple's Safari browser shipped Service Worker support on their browser a few years ago and it's pretty cool to see the usage increase. There has been a significant increase from 14% in 2019 to around 39% this year (so far).

In terms of the number of iPhone users to this site that are controlled by a Service Worker, this number has remained pretty stable with a slight increase this year.


While I realise that my website is just a small blog and is in no way indicative of the global trend, it has been pretty cool to see how usage is changing over many years. When I first wrote about Service Worker and PWAs, it seemed like a pipe dream that Apple would even consider adding support, but as you can see from the data, these numbers are trending in the right direction.