grdpwasm

A web-based RDP client built with Go WebAssembly and grdp. Connect to a Windows Remote Desktop server directly from your browser — no plugins required.

Architecture

Browser (WASM) ──WebSocket──► proxy (Go) ──TCP──► RDP Server

Because browsers cannot open raw TCP sockets, a lightweight Go proxy server bridges WebSocket connections from the browser to the RDP server's TCP port.

Requirements

Go 1.24 or later

A reachable RDP server (Windows or any RDP-compatible host)

Build

git clone https://github.com/nakagami/grdpwasm.git cd grdpwasm make all

make all produces:

Output Description static/main.wasm Go WASM binary (runs in the browser) static/wasm_exec.js Go runtime JS support file proxy/proxy WebSocket-to-TCP proxy + static file server

Run

make serve # or equivalently: ./proxy/proxy -listen :8080 -static static

Then open http://localhost:8080 in your browser.

Proxy options

Flag Default Description -listen :8080 Address and port to listen on -static static Directory to serve static files from

Usage

Open http://localhost:8080 in a browser. Fill in the connection form: Host — hostname or IP address of the RDP server

— hostname or IP address of the RDP server Port — RDP port (default 3389 )

— RDP port (default ) Domain — Windows domain (leave blank for local accounts)

— Windows domain (leave blank for local accounts) User — username

— username Password — password

— password Width / Height — initial desktop resolution Click Connect. The remote desktop appears in the canvas. Click the canvas to capture keyboard focus. Click Disconnect to end the session.

Keyboard & Mouse

All standard keyboard input is forwarded to the remote desktop via RDP scan codes. Mouse move, button clicks, and scroll wheel are fully supported.

Note: The browser tab must have focus for keyboard events to be forwarded. Click inside the canvas area if keys stop responding.

Audio

Remote audio is streamed via RDPSND and played through the browser's Web Audio API (PCM 44100 Hz, stereo, 16-bit signed little-endian).

Security notes

The proxy accepts connections from any origin. Run it only on a trusted network or add authentication before exposing it to the internet.

Credentials are transmitted from the browser to the proxy over WebSocket. Use HTTPS/WSS (put the proxy behind a TLS-terminating reverse proxy such as nginx or Caddy) when accessing it over an untrusted network.

Development

The repository contains a local fork of grdp under ./grdp/ with one addition: a Dialer field on RdpClient that lets callers inject a custom net.Conn factory. This is what allows the WASM build to connect via WebSocket instead of TCP.

make wasm # rebuild only the WASM binary make proxy # rebuild only the proxy server make wasm_exec # refresh wasm_exec.js from the local Go toolchain make clean # remove all build artifacts

License

GPLv3 — see grdp LICENSE.