vite config ssr.noExternal = true causing vercel edge runtime deployment to fail.

[aidenlx]

vite config ssr.noExternal = true causes Vercel edge runtime deployment to fail

Problem Description

When using the official React Router v7 Vercel template with Edge runtime, setting ssr.noExternal = true in the vite.config.ts file causes deployment failures on Vercel with the following error:

Error: The Edge Function "index" is referencing unsupported modules:
- __vc__ns__/0/build/server/edge_eyJydW50aW1lIjoiZWRnZSJ9/index.js: node:stream, crypto, stream

This configuration appears in the official template at: https://github.com/remix-run/react-router-templates/blob/4c84712c10c6189a2770320e0e916559ee87eca5/vercel/vite.config.ts

Reproduction

1. Create a new React Router v7 project using the Vercel template
2. Configure Edge runtime with export const config = { runtime: "edge" }
3. Deploy to Vercel
4. Observe the deployment error related to unsupported Node.js modules

How to Fix

Removing the following configuration from vite.config.ts resolves the issue:

ssr: { 
  noExternal: command === "build" ? true : undefined, 
},

Supporting Information

• A reproduction repository is available at: https://github.com/aidenlx/react-router-v7-on-the-edge
• This was confirmed by Vercel support on March 20, 2025

Environment

• React Router v7
• Vercel deployment platform
• Edge runtime