How to force absolute dev URLs when Vite HTML is re-served by a backend?

[functasti]

Hi,

In a Go backend dev setup, I’m fetching index.html from the Vite dev server and then serving it from a different origin (e.g. http://localhost:8080).

By default, the HTML returned by Vite includes root-relative paths like:

<script type="module" src="/@vite/client"></script>
<script type="module" src="/src/main.jsx"></script>

When this HTML is re-served from another origin, those paths resolve incorrectly.

Is there a supported way to make the dev server emit fully-qualified URLs (e.g. http://localhost:5173/@vite/client) in the injected HTML?

I’ve tried setting server.origin, but the returned HTML still contains root-relative paths.

Is this possible ?

Thanks!

[travisbreaks]

server.origin only affects asset URLs generated by plugins, not the core HTML transforms Vite injects (the /@vite/client script, /src/ imports).

Two approaches that actually work:

Reverse proxy (recommended)

Instead of fetching and re-serving the HTML, proxy Vite-related requests through your Go backend:

go
viteProxy := httputil.NewSingleHostReverseProxy(&url.URL{
Scheme: "http",
Host: "localhost:5173",
})

mux.Handle("/@vite/", viteProxy)
mux.Handle("/src/", viteProxy)
mux.Handle("/node_modules/", viteProxy)


The browser requests resolve against your backend origin, the proxy forwards them to Vite. No URL rewriting needed. This also handles WebSocket HMR connections, which also need to reach the Vite server.

String replace (quick and dirty)

If you need to keep the fetch-and-reserve pattern:

go
html = strings.ReplaceAll(html, "/@vite/client", "http://localhost:5173/@vite/client")
html = strings.ReplaceAll(html, "/src/, "http://localhost:5173/src/)


Not elegant, but predictable. You control exactly what gets rewritten.

The proxy approach is better long-term. It covers HMR, source maps, and any future Vite-injected paths you haven't anticipated.

[functasti]

Thanks for the response.

I need to inject my own state into the HTML, so I’m currently doing string replacement. It works fine, but my concern is indeed whether I’m actually covering all paths- specifically, whether I might be missing some dynamically generated requests created by Vite’s client-side code.

I also have a related question: after the HTML loads, are there certain updates (aside from directly editing the HTML itself) that would cause Vite’s HMR infrastructure to trigger a full page reload instead of a hot update?

[SX110903]

puedes configurar el base y el server.origin en vite.config para que genere las urls absolutas apuntando al servidor de vite:

// vite.config.ts
export default defineConfig({
  server: {
    origin: "http://localhost:5173",
  }
})

con eso el html que devuelve vite ya incluye la url completa en vez del path relativo, asi cuando tu backend de go sirve el html los scripts apuntan al sitio correcto. basicamente le dices a vite desde donde se van a cargar sus assets