[omn1]

Got it. The generator logic is in Rust yes. I could have written it in JavaScript as well but it was just easier for me to do that part in Rust. Should have mentioned that. Of course you could host a static HTML with JS on Github pages, but Github pages also runs on a server. So to answer the original question, yes you do need some server for it unless you make it a command line app.

[ipaddr]

You need a browser and a file. In your example you need a server to make the file and and a browser.

[omn1]

True, but for others to resolve the calendar entries you'd need to serve that file somewhere.

[aaaaaaaaaaab]

You can serve a static HTML page from anywhere. GitHub pages, S3, maybe even Dropbox. Running a Rust binary is an order of magnitude more complex than that.