diff --git a/.gitignore b/.gitignore
index d649445..3d53d11 100755
--- a/.gitignore
+++ b/.gitignore
@@ -43,4 +43,7 @@ tmp/
 temp/
 
 *.zip
-dist
\ No newline at end of file
+dist
+
+*.md
+!README.md
\ No newline at end of file
diff --git a/package.json b/package.json
index 0ba9864..d17a100 100644
--- a/package.json
+++ b/package.json
@@ -6,6 +6,7 @@
   "scripts": {
     "dev": "vite",
     "build": "tsc -b && vite build",
+    "build:mock": "tsc -b && vite build --mode mock",
     "lint": "eslint .",
     "preview": "vite preview"
   },
diff --git a/src/hooks/useCourseData.tsx b/src/hooks/useCourseData.tsx
index 4a75b40..546cf64 100644
--- a/src/hooks/useCourseData.tsx
+++ b/src/hooks/useCourseData.tsx
@@ -14,7 +14,34 @@ export function useCourseData(courses: CourseBase[]) {
   const [remainingTime, setRemainingTime] = useState(0);
   const [isError, setIsError] = useState(false);
 
+  // dev 모드: mock 데이터 로드
+  useEffect(() => {
+    if (!import.meta.env.VITE_MOCK) return;
+    let cancelled = false;
+    import('@/mocks/mockData').then(({ mockVods, mockAssigns, mockQuizes }) => {
+      if (cancelled) return;
+      setVods(mockVods);
+      setAssigns(mockAssigns);
+      setQuizes(mockQuizes);
+      setRefreshTime(new Date().toLocaleTimeString());
+      setRemainingTime(5);
+    });
+    return () => {
+      cancelled = true;
+    };
+  }, []);
+
+  // dev 모드에서는 실제 fetch를 하지 않음
   const updateData = useCallback(async () => {
+    if (import.meta.env.VITE_MOCK) {
+      const { mockVods, mockAssigns, mockQuizes } = await import('@/mocks/mockData');
+      setVods(mockVods);
+      setAssigns(mockAssigns);
+      setQuizes(mockQuizes);
+      setRefreshTime(new Date().toLocaleTimeString());
+      setRemainingTime(0);
+      return;
+    }
     try {
       setIsError(false);
       setIsPending(true);
diff --git a/src/hooks/useGetCourse.ts b/src/hooks/useGetCourse.ts
index 3b908d1..392be39 100644
--- a/src/hooks/useGetCourse.ts
+++ b/src/hooks/useGetCourse.ts
@@ -10,6 +10,14 @@ export interface UseCourseResult {
 export const useGetCourses = (): UseCourseResult => {
   const [courses, setCourses] = useState<CourseBase[]>([]);
   useEffect(() => {
+    if (import.meta.env.VITE_MOCK) {
+      import('@/mocks/mockData').then(({ mockCourses }) => {
+        setCourses(mockCourses);
+        saveDataToStorage('courses', JSON.stringify(mockCourses));
+        console.info('[Dotbugi] DEV 모드: mock 강의 목록 사용');
+      });
+      return;
+    }
     if (!document) return;
     const courseData = Array.from(document.querySelectorAll('.course_box'));
     const data = courseData
diff --git a/src/mocks/mockData.ts b/src/mocks/mockData.ts
new file mode 100644
index 0000000..16253f3
--- /dev/null
+++ b/src/mocks/mockData.ts
@@ -0,0 +1,274 @@
+import { CourseBase, Vod, Assign, Quiz } from '@/content/types';
+
+function offsetDate(days: number, hours = 0): string {
+  const d = new Date();
+  d.setDate(d.getDate() + days);
+  d.setHours(d.getHours() + hours);
+  const pad = (n: number) => String(n).padStart(2, '0');
+  return `${d.getFullYear()}-${pad(d.getMonth() + 1)}-${pad(d.getDate())} ${pad(d.getHours())}:${pad(d.getMinutes())}:${pad(d.getSeconds())}`;
+}
+
+function makeRange(startDays: number, endDays: number): string {
+  return `${offsetDate(startDays)} ~ ${offsetDate(endDays)}`;
+}
+
+export const mockCourses: CourseBase[] = [
+  { courseId: '1001', courseTitle: '자료구조', prof: '김교수' },
+  { courseId: '1002', courseTitle: '운영체제', prof: '이교수' },
+  { courseId: '1003', courseTitle: '컴퓨터네트워크', prof: '박교수' },
+  { courseId: '1004', courseTitle: '데이터베이스', prof: '최교수' },
+];
+
+export const mockVods: Vod[] = [
+  // 출석 완료 + 기간 내
+  {
+    courseId: '1001',
+    courseTitle: '자료구조',
+    prof: '김교수',
+    week: 7,
+    subject: '7주차',
+    title: '이진 탐색 트리',
+    url: '#',
+    range: makeRange(-3, 5),
+    length: '45:00',
+    isAttendance: 'O',
+    weeklyAttendance: '1/1',
+  },
+  // 결석 + 마감 임박 (오늘 안에 끝남)
+  {
+    courseId: '1001',
+    courseTitle: '자료구조',
+    prof: '김교수',
+    week: 7,
+    subject: '7주차',
+    title: '힙과 우선순위 큐',
+    url: '#',
+    range: makeRange(-5, 0, ),
+    length: '38:00',
+    isAttendance: 'X',
+    weeklyAttendance: '0/1',
+  },
+  // 결석 + 기간 여유
+  {
+    courseId: '1002',
+    courseTitle: '운영체제',
+    prof: '이교수',
+    week: 6,
+    subject: '6주차',
+    title: '프로세스 동기화',
+    url: '#',
+    range: makeRange(-2, 7),
+    length: '50:00',
+    isAttendance: 'X',
+    weeklyAttendance: '0/1',
+  },
+  // 출석 완료
+  {
+    courseId: '1002',
+    courseTitle: '운영체제',
+    prof: '이교수',
+    week: 6,
+    subject: '6주차',
+    title: '데드락',
+    url: '#',
+    range: makeRange(-2, 7),
+    length: '42:00',
+    isAttendance: 'O',
+    weeklyAttendance: '1/1',
+  },
+  // 결석 + 마감 매우 임박 (몇 시간 남음)
+  {
+    courseId: '1003',
+    courseTitle: '컴퓨터네트워크',
+    prof: '박교수',
+    week: 5,
+    subject: '5주차',
+    title: 'TCP/IP 프로토콜',
+    url: '#',
+    range: makeRange(-6, 0),
+    length: '55:00',
+    isAttendance: 'X',
+    weeklyAttendance: '0/2',
+  },
+  {
+    courseId: '1003',
+    courseTitle: '컴퓨터네트워크',
+    prof: '박교수',
+    week: 5,
+    subject: '5주차',
+    title: 'UDP와 소켓 프로그래밍',
+    url: '#',
+    range: makeRange(-6, 0),
+    length: '35:00',
+    isAttendance: 'O',
+    weeklyAttendance: '1/2',
+  },
+  // 출석 + range가 넉넉
+  {
+    courseId: '1004',
+    courseTitle: '데이터베이스',
+    prof: '최교수',
+    week: 4,
+    subject: '4주차',
+    title: '정규화 이론',
+    url: '#',
+    range: makeRange(-1, 14),
+    length: '60:00',
+    isAttendance: 'O',
+    weeklyAttendance: '1/1',
+  },
+];
+
+export const mockAssigns: Assign[] = [
+  // 미제출 + 마감 임박 (내일)
+  {
+    courseId: '1001',
+    courseTitle: '자료구조',
+    prof: '김교수',
+    subject: '7주차',
+    title: '이진 트리 구현 과제',
+    url: '#',
+    isSubmit: false,
+    dueDate: offsetDate(1),
+  },
+  // 미제출 + 마감 3일 뒤
+  {
+    courseId: '1002',
+    courseTitle: '운영체제',
+    prof: '이교수',
+    subject: '6주차',
+    title: '프로세스 스케줄링 시뮬레이션',
+    url: '#',
+    isSubmit: false,
+    dueDate: offsetDate(3),
+  },
+  // 제출 완료 + 마감 아직
+  {
+    courseId: '1001',
+    courseTitle: '자료구조',
+    prof: '김교수',
+    subject: '6주차',
+    title: '스택/큐 구현 과제',
+    url: '#',
+    isSubmit: true,
+    dueDate: offsetDate(5),
+  },
+  // 미제출 + 마감 7일 뒤
+  {
+    courseId: '1003',
+    courseTitle: '컴퓨터네트워크',
+    prof: '박교수',
+    subject: '5주차',
+    title: '소켓 프로그래밍 실습',
+    url: '#',
+    isSubmit: false,
+    dueDate: offsetDate(7),
+  },
+  // 제출 완료 + 마감 지남 (새로고침 전 마감 테스트)
+  {
+    courseId: '1004',
+    courseTitle: '데이터베이스',
+    prof: '최교수',
+    subject: '4주차',
+    title: 'SQL 쿼리 작성',
+    url: '#',
+    isSubmit: true,
+    dueDate: offsetDate(-1),
+  },
+  // 미제출 + 마감 몇 시간 뒤 (긴급)
+  {
+    courseId: '1004',
+    courseTitle: '데이터베이스',
+    prof: '최교수',
+    subject: '5주차',
+    title: 'ERD 설계 과제',
+    url: '#',
+    isSubmit: false,
+    dueDate: offsetDate(0, 3),
+  },
+  // 미제출 + 마감 이미 지남 (새로고침 전 마감 테스트)
+  {
+    courseId: '1002',
+    courseTitle: '운영체제',
+    prof: '이교수',
+    subject: '5주차',
+    title: '메모리 관리 보고서',
+    url: '#',
+    isSubmit: false,
+    dueDate: offsetDate(-2),
+  },
+  // dueDate null 케이스
+  {
+    courseId: '1003',
+    courseTitle: '컴퓨터네트워크',
+    prof: '박교수',
+    subject: '6주차',
+    title: '네트워크 분석 레포트',
+    url: '#',
+    isSubmit: false,
+    dueDate: null,
+  },
+];
+
+export const mockQuizes: Quiz[] = [
+  // 마감 임박 (내일)
+  {
+    courseId: '1001',
+    courseTitle: '자료구조',
+    prof: '김교수',
+    subject: '7주차',
+    title: '트리 구조 퀴즈',
+    url: '#',
+    dueDate: offsetDate(1),
+  },
+  // 마감 여유 (5일)
+  {
+    courseId: '1002',
+    courseTitle: '운영체제',
+    prof: '이교수',
+    subject: '6주차',
+    title: '프로세스 관리 퀴즈',
+    url: '#',
+    dueDate: offsetDate(5),
+  },
+  // 마감 몇 시간 뒤 (긴급)
+  {
+    courseId: '1003',
+    courseTitle: '컴퓨터네트워크',
+    prof: '박교수',
+    subject: '5주차',
+    title: 'OSI 모델 퀴즈',
+    url: '#',
+    dueDate: offsetDate(0, 5),
+  },
+  // 마감 이미 지남 (새로고침 전 마감)
+  {
+    courseId: '1004',
+    courseTitle: '데이터베이스',
+    prof: '최교수',
+    subject: '4주차',
+    title: 'SQL 기초 퀴즈',
+    url: '#',
+    dueDate: offsetDate(-1),
+  },
+  // 마감 2주 뒤
+  {
+    courseId: '1004',
+    courseTitle: '데이터베이스',
+    prof: '최교수',
+    subject: '5주차',
+    title: '정규화 퀴즈',
+    url: '#',
+    dueDate: offsetDate(14),
+  },
+  // dueDate null 케이스
+  {
+    courseId: '1001',
+    courseTitle: '자료구조',
+    prof: '김교수',
+    subject: '8주차',
+    title: '그래프 탐색 퀴즈',
+    url: '#',
+    dueDate: null,
+  },
+];
diff --git a/vite.config.ts b/vite.config.ts
index 452c041..0988f39 100755
--- a/vite.config.ts
+++ b/vite.config.ts
@@ -16,7 +16,7 @@ export default defineConfig(({ mode }) => {
       react(),
       tsconfigPaths(),
       Pages(),
-      // dev 환경에서는 crx 플러그인을 제외
+      // dev 서버에서는 crx 플러그인을 제외 (mock 빌드에서는 포함)
       !isDev &&
         crx({
           manifest,