VS Code Build Lights: Broadcasting Success And Failure Over UDP

Make Your Editor Talk To Your Hardware

Most developers rely on on-screen notifications to know whether a build succeeded or failed. But if you’re working across multiple monitors, running CI pipelines, or doing embedded work with long build times, you sometimes want something more physical — like a blinking LED, a buzzer, a display, or even a small dashboard that lights up when things break.

So I built a simple tool that lets VS Code broadcast UDP messages every time a task completes — success or failure — allowing any hardware on your network to react instantly.

This lets you create your own build lights, IoT indicators, or automation triggers with almost zero setup.

Repo: https://github.com/sdrshnptl/notifybuildresult

🛠 What It Does

The extension watches VS Code tasks. Whenever a task ends, it sends a UDP broadcast packet to your LAN.

Example payload:

{  "task": "Build Firmware",  "status": "success"
}

Anything that can listen on UDP (ESP32, Raspberry Pi, Node.js, Python, Arduino, home automation, etc.) can act on it.

This means you can build:

• A green/red RGB LED build status light
• A desktop notifier on your Pi
• A wall-mounted display
• A Slack/Discord notifier (via a UDP-listening script)
• A relay-triggered siren when a build fails (yes, you can…)

⚙️ Why UDP?

UDP broadcast is:

• Zero configuration
• No pairing or auth needed
• Instant and connectionless
• Supported by every IoT chip, MCU, and OS

If your LAN has devices listening on port 10203, they will instantly react to VS Code builds.

UDP is perfect here — even CI systems sometimes use beacons to announce events.

🔧 How It Works Internally

The extension hooks into VS Code’s task lifecycle using its extension API.

When a task finishes, it:

1. Collects task name
2. Determines status (success / fail)
3. Formats a JSON message
4. Sends a broadcast UDP packet

Simplified Flow Diagram

+-------------+       +--------------------+      +-----------------------+
| VS Code     |------>| notifybuildresult  |----->| UDP Broadcast (10203) |
| Task Finish |       | Extension          |      | JSON Payload          |
+-------------+       +--------------------+      +-----------------------+                                                             |                                                             v                                            +-----------------------------+                                            | Any Device Listening on LAN |                                            +-----------------------------+

📡 Example: ESP32 Build Light

Here’s the simplest ESP32 listener:

#include <WiFi.h>
#include <WiFiUdp.h>
#include <ArduinoJson.h>

WiFiUDP udp;

void setup() {  WiFi.begin("ssid", "password");  udp.begin(10203);
}

void loop() {  char buffer[256];  int len = udp.parsePacket();  if (len > 0) {    udp.read(buffer, len);    StaticJsonDocument<256> doc;    deserializeJson(doc, buffer);
    String status = doc["status"];    if (status == "success") digitalWrite(LED_BUILTIN, HIGH);    else digitalWrite(LED_BUILTIN, LOW);  }
}

The LED instantly flips green/red based on your build result.

💻 Node.js Listener (Desktop or Pi)

import dgram from "dgram";

const socket = dgram.createSocket("udp4");
socket.bind(10203, () => console.log("Listening for VS Code build results..."));

socket.on("message", (msg) => {  console.log("Build Event:", msg.toString());
});

One script, infinite possibilities.

🔨 How To Install the Extension

Install from GitHub:

git clone https://github.com/sdrshnptl/notifybuildresult

Or load it manually via VS Code → Extensions → "Install from VSIX".

Full instructions are in the repo.

🧱 Use Cases

✔ Build light for embedded developers ✔ Notify a CNC system (Fanuc, Modbus, ESP32 gateways) ✔ Update a wall display or dashboard ✔ Flash LEDs on your workbench ✔ Trigger home automation when CI breaks ✔ Play sound effects when builds fail

If you can listen to UDP, you can automate it.

🎯 Why I Built It

I work with a lot of embedded, IoT, and automation systems. Builds can take time, and I wanted a simple visual indicator that didn't require switching windows. Most notification systems are cloud-based or require too much overhead.

UDP broadcast is a beautifully simple local-only...