Vendored JavaScript

smiles-drawer.min.js — SmilesDrawer 2.1.7, MIT, © 2017 GDB / Reymond Research Group. Licence in SMILES-DRAWER-LICENSE.txt beside it.

It is vendored rather than fetched from a CDN so the demo keeps the property that makes it cheap: no install, no account, and nothing leaving the visitor's browser. A CDN script would be a third party watching every visitor.

Why draw from SMILES at all, rather than shipping pictures: an RDKit SVG of a molecule averages 8.6 KB and the canvas size barely changes it, because the weight is path data for atoms and bonds — 180×140 gives 8,756 bytes and 96×80 gives 8,634. At 4,096 molecules that is 34 MB of images on top of a 9 MB runtime. A SMILES string is about 50 bytes, so the whole catalogue is 235 KB and the browser draws it.