Service worker is a relatively new technology, leading to a common question: is it safe to use service workers? What we are really asking is, how many browsers support service workers?
The good news is all major browsers have shipped basic service worker support. Chrome has been the leader as they have been largely responsible for initiating the concept and managing the specification. The technology has received enthusiastic support from other browser vendors including Microsoft, FireFox, Samsung, and Opera.
As of the Spring of 2018 all modern browsers had shipped updates to general consumers with at least service worker caching support. Of course, older browsers won't support service workers. But their usage is winding down as consumers upgrade phones and laptops.