I love long URLs and build them into my apps for sharing. You can have powerful apps that are 100% clientside and use just a dumb file web server.
For example, here's a URL that contains both the grammar for a language that compiles to CSS and also example code. Works like a charm.
https://jtree.treenotation.org/designer/#grammar%0A%20toolin...
Having written two apps that do this, I can confirm that it is an amazing technique, and criminally underutilized! My projects store and render entire pages from the URL and encrypt URLs (respectively):