Do Office Add-ins always require Internet access to work?

Question

Let's take Excel for example. In Excel 2016, when I select an add-in in the STORE, after clicking on Trust It, will the code (.html, .js files) of the add-in be downloaded or installed on my machine?

In other words, have the add-ins under MY ADD-INS been already installed on my machine, such that i could load and run them without Internet (if an add-in does not send or receive special data to or from Internet)?

I am asking this question, because i want to know if a basic add-in always requires Internet access to work.

Answer 1

As Eric mentions, Office add-ins are indeed web based. However, to add a bit to his answer:

While you definitely need a one-time access to fetch the manifest and the original HTML/JS/CSS files, if your add-in is not using license checking (it's free) and does not require web services, you should be able to make a website that uses standard offlining techniques to load with no internet connection after the first time.

I tried it out real quick with pointing a manifest at http://html5demos.com/offlineapp. After loading it once and then disconnecting my internet, I was still able to load that page.

Hope this helps,

~ Michael