TanStack Start Server/Client Boundaries

The Problem

TanStack Start uses Vite's environment API to register virtual modules (tanstack-start-injected-head-scripts:v, tanstack-start-manifest:v, etc.) only for the server environment. When you import server-only code at the top level of files that are also bundled for the client, Vite fails to resolve these virtual modules.

Error Signatures

Failed to resolve import "tanstack-start-injected-head-scripts:v"
Failed to resolve import "tanstack-start-manifest:v"
Could not resolve "#tanstack-router-entry"
Could not resolve "#tanstack-start-entry"

Root Cause

Top-level imports from @tanstack/react-start/server in files processed by both client AND server: