diff --git a/README.md b/README.md
index 5422901..55e4300 100644
--- a/README.md
+++ b/README.md
@@ -4,7 +4,7 @@ A comprehensive collection of TypeScript utility functions for modern web develo
 
 ## Features
 
-- 🛠️ **Comprehensive**: String, object, cookie, number, validation, format, search query, device, type, storage and common utilities
+- 🛠️ **Comprehensive**: String, object, cookie, number, validation, format, search query, device, type, storage, easter egg and common utilities
 - 📦 **Tree-shakable**: Import only what you need
 - 🔒 **Type-safe**: Full TypeScript support with type definitions
 - ⚡ **Lightweight**: Minimal dependencies and optimized for performance
@@ -36,6 +36,7 @@ import {
   searchQueryUtil,
   typeUtil,
   deviceUtil,
+  easterEggUtil,
 } from "kr-corekit";
 
 // String utilities
@@ -109,6 +110,10 @@ const isNotPlain = typeUtil.isPlainObject(new Date()); // false
 // Device utilities
 const device = deviceUtil.getDevice(); // { isMobile: false, isTablet: false, isDesktop: true, isIOS: false, isAndroid: false }
 
+// Easter Egg utilities - Encouraging messages for developers
+easterEggUtil.generateHappy(); // [5:28:35 AM] Progress, not perfection. 🚀
+easterEggUtil.generateHappy("Custom message! 🎉"); // [5:28:35 AM] Custom message! 🎉
+
 // Cookie utilities
 cookieUtil.setCookie("theme", "dark");
 const theme = cookieUtil.getCookie("theme");
@@ -125,12 +130,14 @@ For optimal bundle size, import only the functions you need:
 import { escapeHtml, unescapeHtml } from "kr-corekit";
 import { sum, multiply } from "kr-corekit";
 import { clearNullProperties, deepFreeze } from "kr-corekit";
+import { generateHappy } from "kr-corekit";
 
 // Option 2: Import from specific utility modules (good tree-shaking)
 import { escapeHtml } from "kr-corekit/stringUtil";
 import { sum } from "kr-corekit/numberUtil";
 import { clearNullProperties } from "kr-corekit/objectUtil";
 import { storage } from "kr-corekit/commonUtil";
+import { generateHappy } from "kr-corekit/easterEggUtil";
 
 // Usage remains the same
 const escaped = escapeHtml("<div>Hello</div>");
@@ -228,6 +235,10 @@ storage.set("data", { key: "value" });
 
 - `getDevice(): DeviceInfo` - Detects the user's device environment. Returns information about device type (mobile/tablet/desktop) and operating system (iOS/Android). Uses navigator.userAgent for detection and provides safe fallback for SSR environments.
 
+### EasterEggUtil
+
+- `generateHappy(message?: string): string` - Displays encouraging messages to developers in the console with colorful styling and timestamps. Randomly selects from 10 motivational default messages or displays a custom message if provided. Returns the message text. Perfect for adding positivity to development workflows, celebrating test success, or boosting morale during debugging sessions.
+
 ### CookieUtil
 
 - `setCookie(name: string, value: string, options?: object): void` - Sets a cookie
diff --git a/package.json b/package.json
index c2e4dbe..3f1f9e8 100644
--- a/package.json
+++ b/package.json
@@ -79,6 +79,11 @@
       "types": "./dist/types/deviceUtil/index.d.ts",
       "require": "./dist/types/deviceUtil/index.js",
       "import": "./dist/types/deviceUtil/index.js"
+    },
+    "./easterEggUtil": {
+      "types": "./dist/types/easterEggUtil/index.d.ts",
+      "require": "./dist/types/easterEggUtil/index.js",
+      "import": "./dist/types/easterEggUtil/index.js"
     }
   },
   "scripts": {
diff --git a/package/easterEggUtil/generateHappy/README.md b/package/easterEggUtil/generateHappy/README.md
new file mode 100644
index 0000000..f70b3ec
--- /dev/null
+++ b/package/easterEggUtil/generateHappy/README.md
@@ -0,0 +1,134 @@
+# generateHappy()
+
+Display encouraging messages to developers in the console with colorful styling and timestamps.
+
+## Features
+
+- 🎨 **Styled Console Output**: Colorful messages with pink timestamps
+- 🎲 **Random Messages**: 10 motivational default messages
+- 💬 **Custom Messages**: Support for user-defined messages
+- ⏰ **Timestamps**: Automatic timestamp on each message
+- 🎉 **Developer Friendly**: Spread positivity while coding!
+
+## Usage
+
+### Basic Usage (Random Message)
+
+```typescript
+import { generateHappy } from "kr-corekit";
+
+// Displays a random encouraging message
+generateHappy();
+// Console output: [5:28:35 AM] Progress, not perfection. 🚀
+```
+
+### Custom Message
+
+```typescript
+import { generateHappy } from "kr-corekit";
+
+// Display your own encouraging message
+const message = generateHappy("Great job on completing the feature! 🎉");
+console.log(message); // Returns: "Great job on completing the feature! 🎉"
+```
+
+### Tree-Shaking Import
+
+```typescript
+// Import from specific module for better tree-shaking
+import { generateHappy } from "kr-corekit/easterEggUtil";
+
+generateHappy("Keep coding! 💻");
+```
+
+## Default Messages
+
+The function randomly selects from these 10 encouraging messages:
+
+- "Keep going — you're doing great! 💪"
+- "Small steps lead to big changes. 🌱"
+- "Today is a good day to smile. 😊"
+- "You're closer than you think. 🌈"
+- "Stay curious, stay kind. ✨"
+- "Progress, not perfection. 🚀"
+- "You make the code better. 💻❤️"
+- "Breathe. You're doing your best. 🌤️"
+- "Trust the process, enjoy the journey. 🛤️"
+- "Every bug fixed is a victory. 🐞🏆"
+
+## API
+
+### Parameters
+
+- `message?: string` - Optional custom message to display. If not provided, a random default message is used.
+
+### Returns
+
+- `string` - The message that was displayed in the console
+
+## Examples
+
+### In Development Scripts
+
+Add encouraging messages to your build or development scripts:
+
+```typescript
+import { generateHappy } from "kr-corekit";
+
+console.log("Starting development server...");
+generateHappy();
+
+// Your server startup code...
+```
+
+### After Test Success
+
+Celebrate successful tests:
+
+```typescript
+import { generateHappy } from "kr-corekit";
+
+describe("My Tests", () => {
+  afterAll(() => {
+    generateHappy("All tests passed! 🎊");
+  });
+});
+```
+
+### During Debugging
+
+Add morale boosters during long debugging sessions:
+
+```typescript
+import { generateHappy } from "kr-corekit";
+
+function complexDebugFunction() {
+  // ... debugging code ...
+  
+  if (bugFixed) {
+    generateHappy("Bug squashed! 🐛✨");
+  }
+}
+```
+
+## Console Output
+
+The function outputs styled messages to the console with:
+- **Pink timestamp** (`#ff69b4`) with bold font
+- **Dark gray message** (`#333`) with 14px font size
+
+Example output:
+```
+[5:28:35 AM] Progress, not perfection. 🚀
+```
+
+## Notes
+
+- This is a fun utility to add positivity to your development workflow
+- The function uses `console.log` with CSS styling (works in modern browsers)
+- Safe to use in development and can be easily removed for production if needed
+- The timestamp format depends on the user's locale settings
+
+## License
+
+MIT
diff --git a/package/easterEggUtil/generateHappy/index.test.ts b/package/easterEggUtil/generateHappy/index.test.ts
new file mode 100644
index 0000000..7d1e1f8
--- /dev/null
+++ b/package/easterEggUtil/generateHappy/index.test.ts
@@ -0,0 +1,68 @@
+import { describe, test, expect, vi, beforeEach, afterEach } from "vitest";
+import generateHappy from ".";
+
+describe("generateHappy", () => {
+  let consoleLogSpy: ReturnType<typeof vi.spyOn>;
+
+  beforeEach(() => {
+    // console.log를 spy로 대체하여 호출 여부를 추적합니다.
+    consoleLogSpy = vi.spyOn(console, "log").mockImplementation(() => {});
+  });
+
+  afterEach(() => {
+    // 각 테스트 후 spy를 복원합니다.
+    consoleLogSpy.mockRestore();
+  });
+
+  test("사용자 정의 메시지가 없을 때 기본 메시지 중 하나를 반환해야 한다", () => {
+    const result = generateHappy();
+
+    // 기본 메시지 중 하나가 반환되는지 확인 (구체적인 메시지 배열을 하드코딩하지 않음)
+    expect(typeof result).toBe("string");
+    expect(result.length).toBeGreaterThan(0);
+  });
+
+  test("사용자 정의 메시지를 전달하면 해당 메시지를 반환해야 한다", () => {
+    const customMessage = "Custom happy message!";
+    const result = generateHappy(customMessage);
+
+    expect(result).toBe(customMessage);
+  });
+
+  test("console.log가 호출되어야 한다", () => {
+    generateHappy("Test message");
+
+    expect(consoleLogSpy).toHaveBeenCalledTimes(1);
+  });
+
+  test("console.log에 타임스탬프와 메시지가 포함되어야 한다", () => {
+    const testMessage = "Test message";
+    generateHappy(testMessage);
+
+    expect(consoleLogSpy).toHaveBeenCalled();
+    const [firstArg] = consoleLogSpy.mock.calls[0];
+    
+    // 첫 번째 인자에 타임스탬프와 메시지가 포함되어 있는지 확인
+    expect(firstArg).toContain(testMessage);
+    expect(firstArg).toMatch(/\[\d{1,2}:\d{2}:\d{2}.*\]/); // 타임스탬프 형식 확인
+  });
+
+  test("console.log에 올바른 스타일이 적용되어야 한다", () => {
+    generateHappy("Test message");
+
+    expect(consoleLogSpy).toHaveBeenCalled();
+    const args = consoleLogSpy.mock.calls[0];
+    
+    // 스타일 인자들이 올바르게 전달되었는지 확인
+    expect(args[1]).toBe('color: #ff69b4; font-weight: bold;');
+    expect(args[2]).toBe('color: #333; font-size: 14px;');
+  });
+
+  test("여러 번 호출해도 정상적으로 동작해야 한다", () => {
+    generateHappy("Message 1");
+    generateHappy("Message 2");
+    generateHappy();
+
+    expect(consoleLogSpy).toHaveBeenCalledTimes(3);
+  });
+});
diff --git a/package/easterEggUtil/generateHappy/index.ts b/package/easterEggUtil/generateHappy/index.ts
new file mode 100644
index 0000000..bee6ffb
--- /dev/null
+++ b/package/easterEggUtil/generateHappy/index.ts
@@ -0,0 +1,27 @@
+export default function generateHappy(message?: string) {
+  const defaultMessages = [
+    "Keep going — you're doing great! 💪",
+    "Small steps lead to big changes. 🌱",
+    "Today is a good day to smile. 😊",
+    "You're closer than you think. 🌈",
+    "Stay curious, stay kind. ✨",
+    "Progress, not perfection. 🚀",
+    "You make the code better. 💻❤️",
+    "Breathe. You're doing your best. 🌤️",
+    "Trust the process, enjoy the journey. 🛤️",
+    "Every bug fixed is a victory. 🐞🏆",
+  ];
+
+  const text =
+    message ??
+    defaultMessages[Math.floor(Math.random() * defaultMessages.length)];
+  const timestamp = new Date().toLocaleTimeString();
+
+  console.log(
+    `%c[${timestamp}] %c${text}`,
+    'color: #ff69b4; font-weight: bold;',
+    'color: #333; font-size: 14px;'
+  );
+
+  return text;
+}
diff --git a/package/easterEggUtil/index.ts b/package/easterEggUtil/index.ts
new file mode 100644
index 0000000..adba2e9
--- /dev/null
+++ b/package/easterEggUtil/index.ts
@@ -0,0 +1 @@
+export { default as generateHappy } from "./generateHappy";
diff --git a/package/index.ts b/package/index.ts
index 40a1131..f1d66de 100644
--- a/package/index.ts
+++ b/package/index.ts
@@ -9,6 +9,7 @@ export * as searchQueryUtil from "./searchQueryUtil";
 export * as typeUtil from "./typeUtil";
 export * as formatUtil from "./formatUtil";
 export * as deviceUtil from "./deviceUtil";
+export * as easterEggUtil from "./easterEggUtil";
 
 // 개별 함수에 대한 익스포트 진행
 export * from "./stringUtil";
@@ -21,3 +22,4 @@ export * from "./searchQueryUtil";
 export * from "./typeUtil";
 export * from "./formatUtil";
 export * from "./deviceUtil";
+export * from "./easterEggUtil";