Discord server has a system to send messages automatically to a channel.

This system uses webhook, so you just have to send a web request to a URL and a message will be written on the selected channel.

https://en.wikipedia.org/wiki/Webhook

This could be used in many ways, for example:

Make a badge reader using RFID to send a message when someone is at your fablab.
Display the temperature of a room each hour.

Update

Since this tutorial was made, I create a library on Arduino with examples !

Search Discord on the library manager and you will find it

/*

  Send Hello World to Discord using WebHook

*/



#include <Discord_WebHook.h>



Discord_Webhook discord; // Create a Discord_Webhook object

// How to get the Webhook URL

// https://support.discord.com/hc/en-us/articles/228383668-Intro-to-Webhooks

String DISCORD_WEBHOOK = "https://discord.com/api/webhooks/id/token";



void setup() {

  Serial.begin(115200);

  discord.begin(DISCORD_WEBHOOK); // Initialize the Discord_Webhook object

  discord.addWiFi("WiFiName","WiFiPassword"); // Add WiFi credentials (you can add multiples WiFi SSID)

  discord.connectWiFi(); // Connect to WiFi

  discord.send("Hello World"); // Send Hello World to Discord

}



void loop() {



}

Create a Webhook

First we need to create a webhook in our server:

https://support.discordapp.com/hc/en-us/articles/228383668-Intro-to-Webhooks

Click on your discord servername → Discord Settings Then click on Webhook → Create WebHook

Copy the Webhook URL

Arduino Code

I used Arduino Create to write my code, but you can also use the classic IDE.

Here is a link to the code: https://create.arduino.cc/editor/madnerd/429197a3-8a40-4d2c-bc16-1a502cb26cd9/preview

Settings

Settings are inside arduino_secrets.h or the Secrettab

SECRET_SSID: your Wi-Fi network name
SECRET_PASS: your Wi-Fi password
SECRET_WEBHOOK: your Webhook URL without https://discordapp.com
SECRET_TTS: true to enable text to speech or false to disable it

Upload your code on your Arduino MKR 1010, you should see this message:

You can find more information on how to use Discord webhook here: https://discordapp.com/developers/docs/resources/webhook#execute-webhook

Here is also some information for text-to-speech: https://support.discordapp.com/hc/en-us/articles/212517297-Text-to-Speech-101

To send a message on discord, just type:

discord_send("Hello World");

Library

I used two libraries for this code:

WiFiNINA: Wi-Fi manager
ArduinoHttpClient: Web request

🛠️ เจาะลึกเบื้องหลังการทำงาน (Deep Dive / Technical Analysis)

When a security system detects an intruder, sending a simple text message costs money natively. Sending data via Discord is entirely free and incredibly globally instantaneous! The Send a Message on Discord project fundamentally leverages the immense power of the ESP8266 or ESP32 Wi-Fi SoC array. Discord utilizes "Webhooks": hidden internet URLs that immediately print text into a chat channel natively if they receive a properly formatted JSON payload. The ESP8266 executes a heavy HTTPS POST protocol, tunneling securely through the encrypted internet to violently blast alerts straight into your private Discord gaming server!

Negotiating Complex Secure Sockets (HTTPS)

You CANNOT use a standard WiFiClient to talk to Discord. Discord requires heavy https:// encryption. If you send unencrypted text, Discord immediately drops the connection natively!

The ESP8266 MUST use <WiFiClientSecure.h>.
To save memory, instead of validating the entire massively complex Discord SSL Certificate tree natively, developers often utilize client.setInsecure();! This forces the ESP to encrypt the data perfectly without wasting RAM validating the end-server identity!
The board constructs a highly explicit JSON string: {"content": "Motion Detected in Sector 4!"}.

#include <ESP8266WiFi.h>
#include <WiFiClientSecure.h>

const char* discord_webhook = "/api/webhooks/12345/abcde"; // Your massive specific Discord Hash!

void sendDiscordAlert(String message) {
  WiFiClientSecure client;
  client.setInsecure(); // Bypass intense SSL validation to save extreme RAM overhead!

  if (client.connect("discord.com", 443)) { // 443 is the explicit HTTPS Port!
    String jsonPayload = "{\"content\": \"" + message + "\"}"; // Escape quotes natively!
    
    // Construct the massive HTTP POST Request Header block manually!
    client.println("POST " + String(discord_webhook) + " HTTP/1.1");
    client.println("Host: discord.com");
    client.println("Content-Type: application/json");
    client.print("Content-Length: ");
    client.println(jsonPayload.length());
    client.println();
    client.println(jsonPayload); // Blast the JSON body!
    
    Serial.println("DISCORD PAYLOAD INJECTED NATIVELY!");
  }
}

Creating The Discord Webhook

The Arduino code intrinsically requires an endpoint.

Open your Discord Server Server Settings -> Integrations -> Webhooks.
Click "New Webhook". By grabbing the unique URL, Discord grants you a massive cryptographic string (e.g., discord.com/api/webhooks/999.../xxx...).
The Arduino targets this URL explicitly. As long as the ESP has a stable Wi-Fi connection, you can attach an IR sensor, Temperature sensor, or Door switch to immediately summon automated Discord bots natively from physical hardware triggers!

IoT Transmission Hardware Elements

NodeMCU ESP8266 / ESP32 (An Arduino Uno is absolutely useless here; you mandatorily require the heavy Wi-Fi stack and massive RAM allocations natively available on the ESP chips to negotiate the SSL strings!).
A Valid Discord Account and Server (With Administrator privileges to generate Webhooks).
Physical Input Trigger (A PIR Motion Sensor, a basic push-button, or an intense Water Depth sensor to definitively initiate the JSON transmission event sequence natively!).