diff --git a/.gitignore b/.gitignore
index c619ade..a01f19f 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,6 +1,7 @@
 node_modules/
 config/
-data/
+data/notificationHistory.json
+data/ipdaeData.json
 .env
 src/commands/admin/
-src/commands/general/
\ No newline at end of file
+src/commands/general/
diff --git a/src/data/dataManager.js b/src/data/dataManager.js
new file mode 100644
index 0000000..4e0bfdd
--- /dev/null
+++ b/src/data/dataManager.js
@@ -0,0 +1,182 @@
+const { binarySearch, binaryInsert } = require('../utils/helpers');
+const fs = require('fs').promises;
+const logger = require('../../modules/colorfulLogger');
+const {
+    ipdaeDataDirectory,
+    celebrationConfigPath,
+    notificationHistoryPath,
+    dataDir
+} = require('../../config/constants');
+
+let ipdaeDatas = [];
+let celebrationConfig = {};
+let notificationHistory = {};
+
+async function loadData() {
+    try {
+        await fs.mkdir(dataDir, { recursive: true });
+    } catch (e) {
+        logger.error(`Failed to create data directory ${dataDir}: ${e.message}`);
+    }
+
+    try {
+        const data = await fs.readFile(ipdaeDataDirectory, 'utf8');
+        ipdaeDatas = JSON.parse(data);
+        ipdaeDatas.sort((a, b) => a.id.localeCompare(b.id));
+        logger.info('ipdaeData.json loaded and parsed.');
+    } catch (e) {
+        logger.warn(`Failed to load ipdaeData.json: ${e.message}. Initializing as empty array.`);
+        ipdaeDatas = [];
+        if (e.code === 'ENOENT') {
+            await saveData('ipdae');
+        }
+    }
+
+    try {
+        const historyData = await fs.readFile(notificationHistoryPath, 'utf8');
+        notificationHistory = JSON.parse(historyData);
+        logger.info('notificationHistory.json loaded and parsed.');
+    } catch (e) {
+        logger.warn(`notificationHistory.json not found or invalid: ${e.message}. Initializing as empty object.`);
+        notificationHistory = {};
+        if (e.code === 'ENOENT') {
+            await saveData('history');
+        }
+    }
+
+    await migrateData();
+
+    try {
+        const configData = await fs.readFile(celebrationConfigPath, 'utf8');
+        celebrationConfig = JSON.parse(configData);
+        if (celebrationConfig.milestones && Array.isArray(celebrationConfig.milestones)) {
+            celebrationConfig.milestones.forEach(m => {
+                m.mentionUser = m.mentionUser ?? true;
+                m.mentionEveryone = m.mentionEveryone ?? false;
+            });
+        } else {
+            throw new Error("Milestones data is missing or invalid in celebrationConfig.json");
+        }
+        logger.info('celebrationConfig.json loaded and parsed.');
+    } catch (e) {
+        logger.warn(`celebrationConfig.json error: ${e.message}. Creating/Using default config.`);
+        celebrationConfig = {
+            channelTopicKeyword: "전역축하알림",
+            milestones: [
+                { days: 100, message: "🎉 {userName}님, 전역까지 D-100일! 영광의 그날까지 파이팅입니다! 🎉", mentionUser: true, mentionEveryone: false },
+                { days: 50, message: "🥳 {userName}님, 전역까지 D-50일! 이제 절반의 고지를 넘었습니다! 🥳", mentionUser: true, mentionEveryone: false },
+                { days: 30, message: "🗓️ {userName}님, 전역까지 D-30일! 한 달 뒤면 자유의 몸! 🗓️", mentionUser: true, mentionEveryone: false },
+                { days: 7, message: "✨ {userName}님, 전역까지 D-7일! 일주일만 버티면 됩니다! ✨", mentionUser: true, mentionEveryone: false },
+                { days: 1, message: "🚀 {userName}님, 드디어 내일 전역입니다! 사회로 나갈 준비 되셨나요? 🚀", mentionUser: true, mentionEveryone: false },
+                { days: 0, message: "🫡 {userName}님, 🎉축 전역🎉 대한민국의 자랑스러운 아들! 그동안 정말 고 생 많으셨습니다! 🫡", mentionUser: true, mentionEveryone: true }
+            ]
+        };
+        await saveData('config');
+    }
+}
+
+async function migrateData() {
+    let ipdaeDataNeedsSave = false;
+    let notificationHistoryNeedsSave = false;
+
+    for (let i = 0; i < ipdaeDatas.length; i++) {
+        const user = ipdaeDatas[i];
+        if (user.hasOwnProperty('notifiedMilestones')) {
+            if (Array.isArray(user.notifiedMilestones) && user.notifiedMilestones.length > 0) {
+                if (!notificationHistory[user.id] || Object.keys(notificationHistory[user.id]).length === 0) {
+                    notificationHistory[user.id] = [...user.notifiedMilestones];
+                    notificationHistoryNeedsSave = true;
+                    logger.info(`Migrated notifiedMilestones for user ${user.id} to notificationHistory.`);
+                } else {
+                    logger.info(`User ${user.id} already has data in notificationHistory.json. Old notifiedMilestones removed.`);
+                }
+            }
+            delete user.notifiedMilestones;
+            ipdaeDataNeedsSave = true;
+        }
+    }
+
+    if (ipdaeDataNeedsSave) {
+        await saveData('ipdae');
+    }
+    if (notificationHistoryNeedsSave) {
+        await saveData('history');
+    }
+}
+
+async function saveData(type) {
+    try {
+        switch (type) {
+            case 'ipdae':
+                await fs.writeFile(ipdaeDataDirectory, JSON.stringify(ipdaeDatas, null, 4), 'utf8');
+                logger.info('ipdaeData.json saved.');
+                break;
+            case 'config':
+                await fs.writeFile(celebrationConfigPath, JSON.stringify(celebrationConfig, null, 4), 'utf8');
+                logger.info('celebrationConfig.json saved.');
+                break;
+            case 'history':
+                await fs.writeFile(notificationHistoryPath, JSON.stringify(notificationHistory, null, 4), 'utf8');
+                logger.info('notificationHistory.json saved.');
+                break;
+            default:
+                logger.warn(`Unknown data type for saving: ${type}`);
+        }
+    } catch (e) {
+        logger.error(`Error saving ${type} data: ${e.message}`);
+    }
+}
+
+function getIpdaeData() {
+    return ipdaeDatas;
+}
+
+function getCelebrationConfig() {
+    return celebrationConfig;
+}
+
+function getNotificationHistory() {
+    return notificationHistory;
+}
+
+async function updateEnlistmentData(userId, date, type) {
+    let notificationHistoryModified = false;
+    const index = binarySearch(ipdaeDatas, userId);
+
+    if (index !== -1) {
+        const oldDate = ipdaeDatas[index].date;
+        const oldType = ipdaeDatas[index].type;
+
+        ipdaeDatas[index].date = date;
+        ipdaeDatas[index].type = type;
+
+        if (oldDate !== date || oldType !== type) {
+            logger.info(`Enlistment data changed for ${userId}. Resetting their notification history.`);
+            notificationHistory[userId] = [];
+            notificationHistoryModified = true;
+        }
+    } else {
+        binaryInsert(ipdaeDatas, { id: userId, date: date, type: type });
+        notificationHistory[userId] = [];
+        notificationHistoryModified = true;
+    }
+
+    await saveData('ipdae');
+    if (notificationHistoryModified) {
+        await saveData('history');
+    }
+
+    return ipdaeDatas[binarySearch(ipdaeDatas, userId)];
+}
+
+module.exports = {
+    loadData,
+    saveData,
+    getIpdaeData,
+    getCelebrationConfig,
+    getNotificationHistory,
+    updateEnlistmentData,
+    ipdaeDatas,
+    celebrationConfig,
+    notificationHistory
+};
\ No newline at end of file