Browser

Run a Go HTTP server inside a browser tab with the browser-go template.

The browser-go template runs the same http.Handler inside a browser: the Go Wasm module loads in the page and exposes a fetch handler that JavaScript can call directly — no server round-trips. Cloudflare Workers is used only to serve the static page during development and deployment.

Create a project

npm create cloudflare@latest -- --template github.com/syumai/workers-go/_templates/browser/browser-go
cd my-app
go mod init
go mod tidy
npm start

Open http://localhost:8787 in your browser.

How it works

The Wasm build produces a worker.mjs module whose handlers.fetch function accepts a standard Request and returns a Response — the same interface as on Cloudflare Workers. Your page constructs requests and renders the responses.

import handlers from "./build/worker.mjs";

const req = new Request("/add", {
  method: "POST",
  body: JSON.stringify({ a: 1, b: 2 }),
});
const res = await handlers.fetch(req);
const text = await res.text();

On the Go side it is an ordinary http.Handler:

func main() {
	http.HandleFunc("POST /add", func(w http.ResponseWriter, req *http.Request) {
		var addReq AddRequest
		if err := json.NewDecoder(req.Body).Decode(&addReq); err != nil {
			http.Error(w, err.Error(), http.StatusBadRequest)
			return
		}
		json.NewEncoder(w).Encode(addReq.A + addReq.B)
	})
	workers.Serve(nil)
}

Commands

Example project

_examples/browser implements a small calculator API in the browser.