diff --git a/src/app.module.ts b/src/app.module.ts
index 7bdcd79..0b32b28 100644
--- a/src/app.module.ts
+++ b/src/app.module.ts
@@ -6,12 +6,15 @@ import { QuizModule } from './quiz/quiz.module';
 import { QuestModule } from './quest/quest.module';
 import { PhrasesModule } from './phrases/phrases.module';
 import { GrammarModule } from './grammar/grammar.module';
+import { ProgressModule } from './progress/progress.module';
 import { Word } from './words/entities/word.entity';
 import { Phrase } from './phrases/entities/phrase.entity';
 import { GrammarLesson } from './grammar/entities/grammar.entity';
 import { DailyQuest } from './quest/entities/quest.entity';
 import { QuizResult } from './quiz/entities/quiz-result.entity';
 import { Streak } from './quest/entities/streak.entity';
+import { UserProgress } from './progress/entities/user-progress.entity';
+import { StudiedWord } from './progress/entities/studied-word.entity';
 
 @Module({
   imports: [
@@ -22,7 +25,7 @@ import { Streak } from './quest/entities/streak.entity';
       username: 'kakao',
       password: '486251daKWON@',
       database: 'english_study',
-      entities: [Word, Phrase, GrammarLesson, DailyQuest, QuizResult, Streak],
+      entities: [Word, Phrase, GrammarLesson, DailyQuest, QuizResult, Streak, UserProgress, StudiedWord],
       synchronize: true,
     }),
     ScheduleModule.forRoot(),
@@ -31,6 +34,7 @@ import { Streak } from './quest/entities/streak.entity';
     QuestModule,
     PhrasesModule,
     GrammarModule,
+    ProgressModule,
   ],
 })
 export class AppModule {}
diff --git a/src/progress/entities/studied-word.entity.ts b/src/progress/entities/studied-word.entity.ts
new file mode 100644
index 0000000..ca83fb1
--- /dev/null
+++ b/src/progress/entities/studied-word.entity.ts
@@ -0,0 +1,19 @@
+import { Entity, PrimaryGeneratedColumn, Column, CreateDateColumn } from 'typeorm';
+
+@Entity('studied_words')
+export class StudiedWord {
+  @PrimaryGeneratedColumn()
+  id: number;
+
+  @Column()
+  session_id: string;
+
+  @Column()
+  word_id: number;
+
+  @Column({ type: 'date' })
+  studied_date: string;
+
+  @CreateDateColumn()
+  created_at: Date;
+}
diff --git a/src/progress/entities/user-progress.entity.ts b/src/progress/entities/user-progress.entity.ts
new file mode 100644
index 0000000..7368f74
--- /dev/null
+++ b/src/progress/entities/user-progress.entity.ts
@@ -0,0 +1,33 @@
+import { Entity, PrimaryGeneratedColumn, Column } from 'typeorm';
+
+@Entity('user_progress')
+export class UserProgress {
+  @PrimaryGeneratedColumn()
+  id: number;
+
+  @Column({ unique: true })
+  session_id: string;
+
+  @Column({ default: 0 })
+  xp: number;
+
+  @Column({ default: 1 })
+  level: number;
+
+  @Column({ default: 0 })
+  combo: number;
+
+  @Column({ default: 0 })
+  max_combo: number;
+
+  @Column({ type: 'json', nullable: true })
+  badges: string[];
+
+  @Column({ type: 'json', nullable: true })
+  stats: {
+    total_words_studied: number;
+    total_quizzes: number;
+    total_correct: number;
+    wrong_words: { id: number; english: string; korean: string; count: number }[];
+  };
+}
diff --git a/src/progress/progress.controller.ts b/src/progress/progress.controller.ts
new file mode 100644
index 0000000..210ef78
--- /dev/null
+++ b/src/progress/progress.controller.ts
@@ -0,0 +1,32 @@
+import { Controller, Get, Post, Body, Query } from '@nestjs/common';
+import { ProgressService } from './progress.service';
+
+@Controller('progress')
+export class ProgressController {
+  constructor(private readonly service: ProgressService) {}
+
+  @Get('stats')
+  getStats(@Query('session') session: string) {
+    return this.service.getStats(session || 'default');
+  }
+
+  @Post('word')
+  recordWord(@Body() body: { session_id: string; word_id: number }) {
+    return this.service.recordWordStudied(body.session_id, body.word_id);
+  }
+
+  @Post('quiz-answer')
+  recordAnswer(@Body() body: { session_id: string; word_id: number; is_correct: boolean; word?: { english: string; korean: string } }) {
+    return this.service.recordQuizAnswer(body.session_id, body.word_id, body.is_correct, body.word);
+  }
+
+  @Post('quiz-complete')
+  recordComplete(@Body() body: { session_id: string; score: number; total: number }) {
+    return this.service.recordQuizComplete(body.session_id, body.score, body.total);
+  }
+
+  @Get('studied-words')
+  getStudiedWords(@Query('session') session: string, @Query('date') date?: string) {
+    return this.service.getStudiedWordIds(session || 'default', date);
+  }
+}
diff --git a/src/progress/progress.module.ts b/src/progress/progress.module.ts
new file mode 100644
index 0000000..c00c151
--- /dev/null
+++ b/src/progress/progress.module.ts
@@ -0,0 +1,14 @@
+import { Module } from '@nestjs/common';
+import { TypeOrmModule } from '@nestjs/typeorm';
+import { UserProgress } from './entities/user-progress.entity';
+import { StudiedWord } from './entities/studied-word.entity';
+import { ProgressController } from './progress.controller';
+import { ProgressService } from './progress.service';
+
+@Module({
+  imports: [TypeOrmModule.forFeature([UserProgress, StudiedWord])],
+  controllers: [ProgressController],
+  providers: [ProgressService],
+  exports: [ProgressService],
+})
+export class ProgressModule {}
diff --git a/src/progress/progress.service.ts b/src/progress/progress.service.ts
new file mode 100644
index 0000000..4ed45f7
--- /dev/null
+++ b/src/progress/progress.service.ts
@@ -0,0 +1,160 @@
+import { Injectable } from '@nestjs/common';
+import { InjectRepository } from '@nestjs/typeorm';
+import { Repository } from 'typeorm';
+import { UserProgress } from './entities/user-progress.entity';
+import { StudiedWord } from './entities/studied-word.entity';
+
+const LEVEL_THRESHOLDS = [0, 100, 250, 500, 900, 1400, 2100, 3000, 4200, 6000, 10000];
+const BADGES: Record<string, { id: string; name: string; emoji: string; desc: string }> = {
+  first_study: { id: 'first_study', name: '첫 걸음', emoji: '🌱', desc: '첫 단어 학습 완료' },
+  streak_3: { id: 'streak_3', name: '3일 연속', emoji: '🔥', desc: '3일 연속 학습' },
+  streak_7: { id: 'streak_7', name: '일주일', emoji: '💎', desc: '7일 연속 학습' },
+  quiz_perfect: { id: 'quiz_perfect', name: '만점왕', emoji: '🏆', desc: '퀴즈 만점' },
+  combo_5: { id: 'combo_5', name: '5콤보', emoji: '⚡', desc: '5연속 정답' },
+  combo_10: { id: 'combo_10', name: '10콤보', emoji: '🎯', desc: '10연속 정답' },
+  words_50: { id: 'words_50', name: '단어 50', emoji: '📚', desc: '단어 50개 학습' },
+  words_100: { id: 'words_100', name: '단어 100', emoji: '🎓', desc: '단어 100개 학습' },
+  words_500: { id: 'words_500', name: '단어 500', emoji: '👑', desc: '단어 500개 학습' },
+};
+
+@Injectable()
+export class ProgressService {
+  constructor(
+    @InjectRepository(UserProgress) private progressRepo: Repository<UserProgress>,
+    @InjectRepository(StudiedWord) private studiedRepo: Repository<StudiedWord>,
+  ) {}
+
+  private calcLevel(xp: number): number {
+    let lv = 1;
+    for (let i = 1; i < LEVEL_THRESHOLDS.length; i++) {
+      if (xp >= LEVEL_THRESHOLDS[i]) lv = i + 1;
+      else break;
+    }
+    return lv;
+  }
+
+  async getOrCreate(session_id: string): Promise<UserProgress> {
+    let p = await this.progressRepo.findOne({ where: { session_id } });
+    if (!p) {
+      p = this.progressRepo.create({
+        session_id,
+        badges: [],
+        stats: { total_words_studied: 0, total_quizzes: 0, total_correct: 0, wrong_words: [] },
+      });
+      await this.progressRepo.save(p);
+    }
+    if (!p.stats) {
+      p.stats = { total_words_studied: 0, total_quizzes: 0, total_correct: 0, wrong_words: [] };
+    }
+    if (!p.badges) p.badges = [];
+    return p;
+  }
+
+  async recordWordStudied(session_id: string, word_id: number): Promise<{ progress: UserProgress; xpGained: number; newBadges: string[] }> {
+    const today = new Date().toISOString().split('T')[0];
+    const existing = await this.studiedRepo.findOne({ where: { session_id, word_id, studied_date: today } });
+    if (!existing) {
+      await this.studiedRepo.save({ session_id, word_id, studied_date: today });
+    }
+
+    const p = await this.getOrCreate(session_id);
+    const newBadges: string[] = [];
+    p.stats.total_words_studied++;
+
+    const xpGained = 10;
+    p.xp += xpGained;
+    p.level = this.calcLevel(p.xp);
+
+    const checks = [
+      { count: 1, badge: 'first_study' },
+      { count: 50, badge: 'words_50' },
+      { count: 100, badge: 'words_100' },
+      { count: 500, badge: 'words_500' },
+    ];
+    for (const c of checks) {
+      if (p.stats.total_words_studied === c.count && !p.badges.includes(c.badge)) {
+        p.badges.push(c.badge);
+        newBadges.push(c.badge);
+      }
+    }
+
+    await this.progressRepo.save(p);
+    return { progress: p, xpGained, newBadges };
+  }
+
+  async recordQuizAnswer(
+    session_id: string,
+    word_id: number,
+    is_correct: boolean,
+    word_data?: { english: string; korean: string },
+  ): Promise<{ progress: UserProgress; newBadges: string[]; xpGained: number }> {
+    const p = await this.getOrCreate(session_id);
+    const newBadges: string[] = [];
+    let xpGained = 0;
+
+    if (is_correct) {
+      p.combo++;
+      if (p.combo > p.max_combo) p.max_combo = p.combo;
+      const comboBonus = Math.min(p.combo, 10) * 2;
+      xpGained = 20 + comboBonus;
+      p.xp += xpGained;
+      p.stats.total_correct++;
+
+      if (p.combo === 5 && !p.badges.includes('combo_5')) {
+        p.badges.push('combo_5');
+        newBadges.push('combo_5');
+      }
+      if (p.combo === 10 && !p.badges.includes('combo_10')) {
+        p.badges.push('combo_10');
+        newBadges.push('combo_10');
+      }
+    } else {
+      p.combo = 0;
+      xpGained = 5;
+      p.xp += xpGained;
+      if (word_data) {
+        const ww = p.stats.wrong_words || [];
+        const idx = ww.findIndex((w) => w.id === word_id);
+        if (idx >= 0) ww[idx].count++;
+        else ww.push({ id: word_id, english: word_data.english, korean: word_data.korean, count: 1 });
+        p.stats.wrong_words = ww.sort((a, b) => b.count - a.count).slice(0, 50);
+      }
+    }
+
+    p.stats.total_quizzes++;
+    p.level = this.calcLevel(p.xp);
+    await this.progressRepo.save(p);
+    return { progress: p, newBadges, xpGained };
+  }
+
+  async recordQuizComplete(session_id: string, score: number, total: number): Promise<UserProgress> {
+    const p = await this.getOrCreate(session_id);
+    if (score === total && !p.badges.includes('quiz_perfect')) {
+      p.badges.push('quiz_perfect');
+    }
+    return this.progressRepo.save(p);
+  }
+
+  async getStudiedWordIds(session_id: string, date?: string): Promise<number[]> {
+    const d = date || new Date().toISOString().split('T')[0];
+    const rows = await this.studiedRepo.find({ where: { session_id, studied_date: d } });
+    return rows.map((r) => r.word_id);
+  }
+
+  async getStats(session_id: string) {
+    const p = await this.getOrCreate(session_id);
+    const currentLevelXp = LEVEL_THRESHOLDS[p.level - 1] || 0;
+    const nextLevelXp = LEVEL_THRESHOLDS[p.level] || LEVEL_THRESHOLDS[LEVEL_THRESHOLDS.length - 1];
+    const allBadges = Object.values(BADGES).map((b) => ({ ...b, earned: p.badges.includes(b.id) }));
+
+    return {
+      ...p,
+      currentLevelXp,
+      nextLevelXp,
+      xpProgress: p.xp - currentLevelXp,
+      xpRange: nextLevelXp - currentLevelXp,
+      xpToNextLevel: nextLevelXp - p.xp,
+      allBadges,
+    };
+  }
+}
diff --git a/src/quiz/quiz.controller.ts b/src/quiz/quiz.controller.ts
index 414ce6f..2a62c0a 100644
--- a/src/quiz/quiz.controller.ts
+++ b/src/quiz/quiz.controller.ts
@@ -4,8 +4,19 @@ import { QuizService } from './quiz.service';
 @Controller('quiz')
 export class QuizController {
   constructor(private readonly service: QuizService) {}
-  @Get('generate') generate(@Query('count') count?: string) { return this.service.generateQuiz(count ? +count : 5); }
-  @Post('result') saveResult(@Body() body: { session_id: string; score: number; total: number }) {
+
+  @Get('generate')
+  generate(
+    @Query('count') count?: string,
+    @Query('difficulty') difficulty?: string,
+    @Query('studied') studied?: string,
+  ) {
+    const ids = studied ? studied.split(',').map(Number).filter(Boolean) : undefined;
+    return this.service.generateQuiz(count ? +count : 10, difficulty, ids);
+  }
+
+  @Post('result')
+  saveResult(@Body() body: { session_id: string; score: number; total: number }) {
     return this.service.saveResult(body.session_id, body.score, body.total);
   }
 }
diff --git a/src/quiz/quiz.service.ts b/src/quiz/quiz.service.ts
index 93df5b6..59d0e22 100644
--- a/src/quiz/quiz.service.ts
+++ b/src/quiz/quiz.service.ts
@@ -11,18 +11,31 @@ export class QuizService {
     private wordsService: WordsService,
   ) {}
 
-  async generateQuiz(count = 5) {
-    const words = await this.wordsService.getQuizWords(count + 12);
-    const selected = words.slice(0, count);
-    const pool = words.slice(count);
+  async generateQuiz(count = 10, difficulty?: string, studiedWordIds?: number[]) {
+    let pool: any[];
+
+    if (studiedWordIds && studiedWordIds.length >= 4) {
+      const studied = await this.wordsService.findByIds(studiedWordIds);
+      const extra = await this.wordsService.getQuizWords(count + 20, difficulty);
+      const extraFiltered = extra.filter((w) => !studiedWordIds.includes(w.id));
+      pool = [...studied, ...extraFiltered].sort(() => Math.random() - 0.5);
+    } else {
+      pool = (await this.wordsService.getQuizWords(count + 20, difficulty)).sort(() => Math.random() - 0.5);
+    }
+
+    const selected = pool.slice(0, count);
+    const wrongPool = pool.slice(count);
 
     return selected.map((word) => {
-      const wrong = pool.sort(() => Math.random() - 0.5).slice(0, 3);
-      const choices = [word.korean, ...wrong.map((w) => w.korean)].sort(() => Math.random() - 0.5);
+      const wrong = wrongPool.sort(() => Math.random() - 0.5).slice(0, 3);
+      const choices = [word.korean, ...wrong.map((w: any) => w.korean)].sort(() => Math.random() - 0.5);
       return {
         id: word.id,
         english: word.english,
+        korean: word.korean,
         pronunciation: word.pronunciation,
+        category: word.category,
+        difficulty: word.difficulty,
         answer: word.korean,
         choices,
       };
diff --git a/src/words/words.service.ts b/src/words/words.service.ts
index 3db1bd1..fec5683 100644
--- a/src/words/words.service.ts
+++ b/src/words/words.service.ts
@@ -1,6 +1,6 @@
 import { Injectable } from '@nestjs/common';
 import { InjectRepository } from '@nestjs/typeorm';
-import { Repository } from 'typeorm';
+import { Repository, In } from 'typeorm';
 import { Word } from './entities/word.entity';
 
 @Injectable()
@@ -12,17 +12,25 @@ export class WordsService {
     return this.repo.find();
   }
 
-  findByCategory(category: string) {
-    return this.repo.find({ where: { category } });
+  findByIds(ids: number[]): Promise<Word[]> {
+    if (!ids.length) return Promise.resolve([]);
+    return this.repo.find({ where: { id: In(ids) } });
   }
 
   async getDailyWords(): Promise<Word[]> {
     const today = new Date().toISOString().split('T')[0];
     const existing = await this.repo.find({ where: { daily_date: today, is_daily: true } });
-    if (existing.length >= 5) return existing;
+    if (existing.length >= 10) return existing.slice(0, 10);
+
+    await this.repo
+      .createQueryBuilder()
+      .update(Word)
+      .set({ is_daily: false, daily_date: null })
+      .where('daily_date = :today AND is_daily = true', { today })
+      .execute();
 
     const all = await this.repo.find();
-    const shuffled = all.sort(() => Math.random() - 0.5).slice(0, 5);
+    const shuffled = all.sort(() => Math.random() - 0.5).slice(0, 10);
     for (const w of shuffled) {
       w.is_daily = true;
       w.daily_date = today;
@@ -30,8 +38,14 @@ export class WordsService {
     return this.repo.save(shuffled);
   }
 
-  async getQuizWords(count = 10): Promise<Word[]> {
-    const all = await this.repo.find();
+  async getQuizWords(count = 10, difficulty?: string, ids?: number[]): Promise<Word[]> {
+    let query = this.repo.createQueryBuilder('w');
+    if (difficulty) query = query.where('w.difficulty = :difficulty', { difficulty });
+    if (ids && ids.length) {
+      const clause = difficulty ? 'andWhere' : 'where';
+      query = query[clause]('w.id IN (:...ids)', { ids });
+    }
+    const all = await query.getMany();
     return all.sort(() => Math.random() - 0.5).slice(0, count);
   }