Hello, @user101, and welcome to the Processing Community!
See the page p5.js: Get Started.
Note this on the page:
If you look in index.html, you’ll notice that it links to the file p5.js. If you would like to use the minified version (compressed for faster page loading), change the link to p5.min.js.
That minified file is less than a megabyte in size. Adapt the link to the location from which you serve the file.
EDIT (October 23, 2021):
Depending upon the particulars of a given sketch that you host, the user might only need to be served the following:
- Your .html file
- Your .js sketch file
- Your .css file
In total, that might be less than a megabyte.