I have long encouraged students to turn software demos (which work on their laptop, in their terminal, and maybe nowhere else) into simple web apps. Years ago I built a demo of what this might look like, using Python’s Flask library. The entire app is under 200 lines of Python (and jinja2 template), plus a bit of static HTML and CSS.
It turns out this little demonstration is actually quite useful for my research. For any given string, it gives you the full decomposition of it into Unicode codepoints, with optional Unicode normalization, whitespace stripping, and case-folding. This is very useful for debugging.
The Unicoder, as it is called, is hosted on the free tier of Glitch. [Edit: it is now on Render.] (It used to also be on Heroku, but Salesforce is actively pushing people off that very useful platform.) Because of that, it takes about 10 seconds to “start up” (i.e., I assume the workers are put into some kind of hibernation mode) if it hasn’t been used in the last half hour or so. But, it’s very, very useful.