I just noticed that on the latest MacOS Ventura 13.3.1 with Safari 16.4, the navigator.clipboard API is not accessible under plain HTTP .test domains, used with puma-dev for example. It returns “property is undefined” type of error.

The solution is to switch to HTTPS. With puma-dev this is simple, as it comes out of box with support for secure connections.

I haven’t had a chance to test it with plain old localhost yet, but I figured to post this, in case it trips you too.