Fetch doesn't work propery in Cloudflare Workers + vite dev

[thomasgauvin]

What versions & operating system are you using?

Wrangler 4.20.0

Please provide a link to a minimal reproduction

No response

Describe the Bug

Fetch returns errors for a Cloudflare Workers + Vite project when developing locally (empty JSON body), but no issues once deployed. This makes it a non-starter for developing Workers + Vite projects with proxying/fetching involved. Non-Vite projects which have no errors.

Here is a repro: https://github.com/thomasgauvin/cloudflare-workers-vite-fetch-error Here is the same code, no errors for local development when not using Vite: https://github.com/thomasgauvin/cloudflare-workers-simple-hono-proxy

Please provide any relevant error logs

No response