diff --git a/BackendAcademy/src/app.module.ts b/BackendAcademy/src/app.module.ts
index caade999b..e95c2b6c9 100644
--- a/BackendAcademy/src/app.module.ts
+++ b/BackendAcademy/src/app.module.ts
@@ -20,16 +20,6 @@ import { SocialModule } from './social/social.module';
 import { OnboardingModule } from './onboarding/onboarding.module';
 import { LessonModule } from './lessons/lesson.module';
 import { TaskModule } from './tasks/task.module';
-import { JobsModule } from './jobs/jobs.module';
-import { LoggingModule } from './logging/logging.module';
-import { ProgressModule } from './courses/progress/progress.module';
-import { AppConfigModule } from './config/config.module';
-import { ContractsModule } from './contracts/contracts.module';
-import { AssetsModule } from './assets/assets.module';
-import { PathfindingModule } from './pathfinding/pathfinding.module';
-import { MonitoringModule } from './monitoring/monitoring.module';
-import { SearchModule } from './search/search.module';
-import { PaymentsModule } from './payments/payments.module';
 import { SessionsModule } from './sessions/sessions.module';
 
 @Module({
diff --git a/BackendAcademy/src/sessions/attendance.controller.ts b/BackendAcademy/src/sessions/attendance.controller.ts
new file mode 100644
index 000000000..38cb3ab6d
--- /dev/null
+++ b/BackendAcademy/src/sessions/attendance.controller.ts
@@ -0,0 +1,43 @@
+import { Body, Controller, Get, Param, Post } from '@nestjs/common';
+import { AttendanceService } from './attendance.service';
+import { JoinSessionAttendanceDto } from './dto/join-session-attendance.dto';
+import { LeaveSessionAttendanceDto } from './dto/leave-session-attendance.dto';
+
+@Controller('sessions/attendance')
+export class AttendanceController {
+  constructor(private readonly attendanceService: AttendanceService) {}
+
+  @Post('join')
+  async join(@Body() dto: JoinSessionAttendanceDto) {
+    const record = await this.attendanceService.join(dto.sessionKey, dto.userId);
+    return {
+      id: record.id,
+      sessionKey: record.sessionKey,
+      userId: record.userId,
+      joinedAt: record.joinedAt,
+      leftAt: record.leftAt,
+      durationSeconds: record.durationSeconds,
+      isActive: record.isActive,
+    };
+  }
+
+  @Post('leave')
+  async leave(@Body() dto: LeaveSessionAttendanceDto) {
+    const record = await this.attendanceService.leave(dto.sessionKey, dto.userId);
+    return {
+      id: record.id,
+      sessionKey: record.sessionKey,
+      userId: record.userId,
+      joinedAt: record.joinedAt,
+      leftAt: record.leftAt,
+      durationSeconds: record.durationSeconds,
+      isActive: record.isActive,
+    };
+  }
+
+  @Get(':sessionKey/stats')
+  async stats(@Param('sessionKey') sessionKey: string) {
+    return this.attendanceService.getSessionStats(sessionKey);
+  }
+}
+
diff --git a/BackendAcademy/src/sessions/attendance.entity.ts b/BackendAcademy/src/sessions/attendance.entity.ts
new file mode 100644
index 000000000..cd20bc357
--- /dev/null
+++ b/BackendAcademy/src/sessions/attendance.entity.ts
@@ -0,0 +1,27 @@
+import { Column, CreateDateColumn, Entity, Index, PrimaryGeneratedColumn } from 'typeorm';
+
+@Entity('session_attendance')
+@Index(['sessionKey', 'userId'], { unique: false })
+export class AttendanceEntity {
+  @PrimaryGeneratedColumn('uuid')
+  id!: string;
+
+  @Column({ type: 'varchar', length: 128 })
+  sessionKey!: string;
+
+  @Column({ type: 'varchar', length: 128 })
+  userId!: string;
+
+  @CreateDateColumn({ type: 'timestamptz' })
+  joinedAt!: Date;
+
+  @Column({ type: 'timestamptz', nullable: true })
+  leftAt: Date | null = null;
+
+  @Column({ type: 'int', nullable: true })
+  durationSeconds: number | null = null;
+
+  @Column({ type: 'boolean', default: true })
+  isActive!: boolean;
+}
+
diff --git a/BackendAcademy/src/sessions/attendance.service.ts b/BackendAcademy/src/sessions/attendance.service.ts
new file mode 100644
index 000000000..247dbafa2
--- /dev/null
+++ b/BackendAcademy/src/sessions/attendance.service.ts
@@ -0,0 +1,90 @@
+import { BadRequestException, Injectable } from '@nestjs/common';
+import { InjectRepository } from '@nestjs/typeorm';
+import { Repository } from 'typeorm';
+import { AttendanceEntity } from './attendance.entity';
+
+@Injectable()
+export class AttendanceService {
+  constructor(
+    @InjectRepository(AttendanceEntity)
+    private readonly attendanceRepo: Repository<AttendanceEntity>,
+  ) {}
+
+  async join(sessionKey: string, userId: string): Promise<AttendanceEntity> {
+    const now = new Date();
+
+    const existing = await this.attendanceRepo.findOne({
+      where: {
+        sessionKey,
+        userId,
+        isActive: true,
+      },
+      order: { joinedAt: 'DESC' },
+    });
+
+    if (existing) {
+      return existing;
+    }
+
+    const record = this.attendanceRepo.create({
+      sessionKey,
+      userId,
+      joinedAt: now,
+      isActive: true,
+      leftAt: null,
+      durationSeconds: null,
+    });
+
+    return this.attendanceRepo.save(record);
+  }
+
+  async leave(sessionKey: string, userId: string): Promise<AttendanceEntity> {
+    const existing = await this.attendanceRepo.findOne({
+      where: {
+        sessionKey,
+        userId,
+        isActive: true,
+      },
+      order: { joinedAt: 'DESC' },
+    });
+
+    if (!existing) {
+      throw new BadRequestException('No active attendance found for this user/session');
+    }
+
+    const now = new Date();
+    const durationMs = now.getTime() - existing.joinedAt.getTime();
+    const durationSeconds = Math.max(0, Math.floor(durationMs / 1000));
+
+    existing.isActive = false;
+    existing.leftAt = now;
+    existing.durationSeconds = durationSeconds;
+
+    return this.attendanceRepo.save(existing);
+  }
+
+  async getSessionStats(sessionKey: string): Promise<{
+    presentCount: number;
+    totalJoins: number;
+    totalDurationSeconds: number;
+  }> {
+    const active = await this.attendanceRepo.count({
+      where: {
+        sessionKey,
+        isActive: true,
+      },
+    });
+
+    const all = await this.attendanceRepo.find({ where: { sessionKey } });
+
+    const totalJoins = all.length;
+    const totalDurationSeconds = all.reduce((acc, r) => acc + (r.durationSeconds ?? 0), 0);
+
+    return {
+      presentCount: active,
+      totalJoins,
+      totalDurationSeconds,
+    };
+  }
+}
+
diff --git a/BackendAcademy/src/sessions/dto/get-session-attendance-stats.dto.ts b/BackendAcademy/src/sessions/dto/get-session-attendance-stats.dto.ts
new file mode 100644
index 000000000..33492c779
--- /dev/null
+++ b/BackendAcademy/src/sessions/dto/get-session-attendance-stats.dto.ts
@@ -0,0 +1,18 @@
+import { IsInt, IsNotEmpty, IsObject, IsOptional, IsString, MaxLength, ValidateNested } from 'class-validator';
+
+export class SessionAttendanceStatsDto {
+  @IsString()
+  @IsNotEmpty()
+  @MaxLength(128)
+  sessionKey!: string;
+
+  @IsInt()
+  presentCount!: number;
+
+  @IsInt()
+  totalJoins!: number;
+
+  @IsInt()
+  totalDurationSeconds!: number;
+}
+
diff --git a/BackendAcademy/src/sessions/dto/join-session-attendance.dto.ts b/BackendAcademy/src/sessions/dto/join-session-attendance.dto.ts
new file mode 100644
index 000000000..498876e5c
--- /dev/null
+++ b/BackendAcademy/src/sessions/dto/join-session-attendance.dto.ts
@@ -0,0 +1,14 @@
+import { IsNotEmpty, IsString, MaxLength } from 'class-validator';
+
+export class JoinSessionAttendanceDto {
+  @IsString()
+  @IsNotEmpty()
+  @MaxLength(128)
+  sessionKey!: string;
+
+  @IsString()
+  @IsNotEmpty()
+  @MaxLength(128)
+  userId!: string;
+}
+
diff --git a/BackendAcademy/src/sessions/dto/leave-session-attendance.dto.ts b/BackendAcademy/src/sessions/dto/leave-session-attendance.dto.ts
new file mode 100644
index 000000000..d1e24ef77
--- /dev/null
+++ b/BackendAcademy/src/sessions/dto/leave-session-attendance.dto.ts
@@ -0,0 +1,14 @@
+import { IsNotEmpty, IsString, MaxLength } from 'class-validator';
+
+export class LeaveSessionAttendanceDto {
+  @IsString()
+  @IsNotEmpty()
+  @MaxLength(128)
+  sessionKey!: string;
+
+  @IsString()
+  @IsNotEmpty()
+  @MaxLength(128)
+  userId!: string;
+}
+
diff --git a/BackendAcademy/src/sessions/sessions.module.ts b/BackendAcademy/src/sessions/sessions.module.ts
index c164b2c0c..e02a7ba79 100644
--- a/BackendAcademy/src/sessions/sessions.module.ts
+++ b/BackendAcademy/src/sessions/sessions.module.ts
@@ -1,10 +1,14 @@
 import { Module } from '@nestjs/common';
-import { OfficeHoursController } from './office-hours.controller';
-import { OfficeHoursService } from './office-hours.service';
+import { TypeOrmModule } from '@nestjs/typeorm';
+import { AttendanceEntity } from './attendance.entity';
+import { AttendanceController } from './attendance.controller';
+import { AttendanceService } from './attendance.service';
 
 @Module({
-  controllers: [OfficeHoursController],
-  providers: [OfficeHoursService],
-  exports: [OfficeHoursService],
+  imports: [TypeOrmModule.forFeature([AttendanceEntity])],
+  controllers: [AttendanceController],
+  providers: [AttendanceService],
+  exports: [AttendanceService],
 })
 export class SessionsModule {}
+
diff --git a/TODO.md b/TODO.md
new file mode 100644
index 000000000..73d01f883
--- /dev/null
+++ b/TODO.md
@@ -0,0 +1,33 @@
+# TODO - Live session attendance tracking (BackendAcademy)
+
+## Step 1: Add persistence model
+- Create `BackendAcademy/src/sessions/attendance.entity.ts` using TypeORM.
+- Decide primary key and fields: `sessionKey`, `userId`, `joinedAt`, `leftAt`, `durationSeconds`.
+
+## Step 2: Implement attendance service
+- Create `BackendAcademy/src/sessions/attendance.service.ts`.
+- Add methods: `join`, `leave`, `getSessionStats`.
+- Join is idempotent per `(sessionKey,userId)` while active.
+
+## Step 3: Implement controller + DTOs
+- Create `BackendAcademy/src/sessions/dto/join-session-attendance.dto.ts`.
+- Create `BackendAcademy/src/sessions/dto/leave-session-attendance.dto.ts`.
+- Create `BackendAcademy/src/sessions/dto/get-session-attendance-stats.dto.ts` (if needed).
+- Create `BackendAcademy/src/sessions/attendance.controller.ts` with endpoints:
+  - `POST /api/v1/sessions/attendance/join`
+  - `POST /api/v1/sessions/attendance/leave`
+  - `GET /api/v1/sessions/attendance/:sessionKey/stats`
+
+## Step 4: Add NestJS module wiring
+- Create `BackendAcademy/src/sessions/sessions.module.ts` and register TypeORM entity + providers.
+
+## Step 5: Wire into app
+- Update `BackendAcademy/src/app.module.ts` to import `SessionsModule`.
+
+## Step 6: Verify build
+- Run `npm run build` (or `npm test`) inside `BackendAcademy`.
+
+## Progress
+- Step 1-5 implemented (sessions module + attendance tracking).
+
+