Coping with JavaScript cross-Runtime Incompatibilities

Moving from Node.js to Bun, Cloudflare Workerd, or Vercel Edge sounds straightforward — until your database driver stops working or your markdown library throws at import time. The JavaScript runtime landscape has fragmented, and most popular packages were never tested beyond Node.

I shared firsthand experience refactoring libraries to support Cloudflare Workers and Bun: which incompatibilities bite hardest, how to detect them early, and what the open-source community can do to reduce this friction long-term.