You're building on Cloudflare Workers and you need to write values into a PDF form — an invoice, a contract, a government form. You reach for the thing you used last time: headless Chrome, or a PDF library bundled into a Lambda. On Workers, neither one fits. Chrome won't run in a V8 isolate, and standing up a Lambda just to render a PDF drags a whole second runtime into an app that didn't need one. The fill itself is one HTTP call. Here's the minimal Worker, and the reason the hosting substrate — not the PDF code — is the part that actually matters.
Why headless Chrome doesn't fit Workers
The default way to "make a PDF in JavaScript" for the last decade has been Puppeteer driving headless Chrome: render HTML, call page.pdf(), done. It works on a normal Node server or a fat Lambda with a Chromium layer. It does not work on Cloudflare Workers, and the reason is architectural, not a missing flag. A Worker runs in a V8 isolate — the same engine Chrome uses, but with no operating system underneath it. There's no filesystem, no ability to spawn a subprocess, and a hard memory and CPU-time budget per request. Headless Chrome is an entire browser binary that expects all of those things. You can't bundle a ~150 MB browser into a Worker, and even if you could, there's nothing to exec() it.
