uptime-kuma/server/notification-providers/webhook.js

const NotificationProvider = require("./notification-provider");
const axios = require("axios");
const FormData = require("form-data");

class Webhook extends NotificationProvider {

    name = "webhook";

    async send(notification, msg, monitorJSON = null, heartbeatJSON = null) {
        let okMsg = "Sent Successfully. ";

        try {
            let data = {
                heartbeat: heartbeatJSON,
                monitor: monitorJSON,
                msg,
            };
            let finalData;
            let config = {};

            if (notification.webhookContentType === "form-data") {
                finalData = new FormData();
                finalData.append("data", JSON.stringify(data));

                config = {
                    headers: finalData.getHeaders(),
                }

            } else {
                finalData = data;
            }

            await axios.post(notification.webhookURL, finalData, config)
            return okMsg;

        } catch (error) {
            this.throwGeneralAxiosError(error)
        }

    }

}

module.exports = Webhook;