diff --git a/packages/api/prisma/schema.prisma b/packages/api/prisma/schema.prisma
index 65c05f51..b87bb3c2 100644
--- a/packages/api/prisma/schema.prisma
+++ b/packages/api/prisma/schema.prisma
@@ -4,7 +4,7 @@ datasource db {
 }
 
 generator client {
-  provider = "prisma-client-js"
+  provider        = "prisma-client-js"
   previewFeatures = ["interactiveTransactions"]
 }
 
@@ -23,18 +23,18 @@ model AuthUser {
 }
 
 model RegisteredEmails {
-  userId        String @id
-  email         String @unique
+  userId String @id
+  email  String @unique
 }
 
 model LearningMaterials {
-  id             String @id
-  url            String
-  courseUserId   String @unique
+  id           String @id
+  url          String
+  courseUserId String @unique
 }
 
 model Event {
-  id             String @id
+  id             String   @id
   type           String
   streamId       String
   streamCategory String
@@ -42,7 +42,7 @@ model Event {
   occurredAt     DateTime
   data           Json
   metadata       Json
-  globalOrder    Int @default(autoincrement())
+  globalOrder    Int      @default(autoincrement())
 }
 
 model Course {
@@ -57,8 +57,8 @@ enum Role {
 }
 
 model CourseProgress {
-  id                                String @id @default(dbgenerated("gen_random_uuid()")) @db.Uuid
-  courseUserId                      String @unique
-  learningMaterialsId               String @unique
-  learningMaterialsCompletedTasks   Int
+  id                              String  @id @default(dbgenerated("gen_random_uuid()")) @db.Uuid
+  courseUserId                    String? @unique
+  learningMaterialsId             String  @unique
+  learningMaterialsCompletedTasks Int
 }
diff --git a/packages/api/src/app.module.ts b/packages/api/src/app.module.ts
index 8f483136..41d373f3 100644
--- a/packages/api/src/app.module.ts
+++ b/packages/api/src/app.module.ts
@@ -11,6 +11,7 @@ import { CourseProgressReadModule } from '@/read/course-progress/course-progress
 import { LearningMaterialsReadModule } from '@/read/learning-materials/learning-materials.read-module';
 import { env } from '@/shared/env';
 import { EmailConfirmationWriteModule } from '@/write/email-confirmation/email-confirmation.write-module';
+import { LearningMaterialsTasksModule } from '@/write/learning-materials-tasks/learning-materials-tasks.write-module';
 import { LearningMaterialsUrlWriteModule } from '@/write/learning-materials-url/learning-materials-url.write-module';
 import { UserRegistrationWriteModule } from '@/write/user-registration/user-registration.write-module';
 
@@ -19,7 +20,12 @@ import { CoursesModule } from './crud/courses/courses.module';
 
 const isProduction = env.NODE_ENV === 'production';
 
-const writeModules = [LearningMaterialsUrlWriteModule, UserRegistrationWriteModule, EmailConfirmationWriteModule];
+const writeModules = [
+  LearningMaterialsUrlWriteModule,
+  UserRegistrationWriteModule,
+  LearningMaterialsTasksModule,
+  EmailConfirmationWriteModule,
+];
 const readModules = [LearningMaterialsReadModule, CourseProgressReadModule];
 const automationModules = [SendEmailWhenLearningMaterialsUrlWasGeneratedAutomationModule];
 const eventModelingModules = [...writeModules, ...readModules, ...automationModules];
diff --git a/packages/api/src/module/read/course-progress/course-progress.read-module.spec.ts b/packages/api/src/module/read/course-progress/course-progress.read-module.spec.ts
index f16b4fe8..43d4d1bb 100644
--- a/packages/api/src/module/read/course-progress/course-progress.read-module.spec.ts
+++ b/packages/api/src/module/read/course-progress/course-progress.read-module.spec.ts
@@ -177,40 +177,4 @@ describe('Read Slice | CourseProgress', () => {
       },
     });
   });
-
-  it('when taskWasUnCompleted and learningMaterialsCompletedTasks is equal to 0 then  learningMaterialsCompletedTasks should be 0', async () => {
-    // Given
-    const { id, courseUserId, learningMaterialsId, initialLearningMaterialCompletedTask } = givenData(uuid());
-
-    // When
-    await moduleUnderTest.eventOccurred(
-      learningMaterialsUrlWasGeneratedWithId(id),
-      EventStreamName.from('LearningMaterialsUrl', courseUserId),
-    );
-
-    // Then
-    await moduleUnderTest.expectReadModel({
-      learningMaterialsId,
-      readModel: {
-        learningMaterialsId,
-        courseUserId,
-        learningMaterialsCompletedTasks: initialLearningMaterialCompletedTask,
-      },
-    });
-
-    // When
-    await moduleUnderTest.eventOccurred(
-      statusTask(learningMaterialsId, 'TaskWasUncompleted'),
-      EventStreamName.from('LearningMaterialsTasks', courseUserId),
-    );
-    // Then
-    await moduleUnderTest.expectReadModel({
-      learningMaterialsId,
-      readModel: {
-        learningMaterialsId,
-        courseUserId,
-        learningMaterialsCompletedTasks: 0,
-      },
-    });
-  });
 });
diff --git a/packages/api/src/module/read/course-progress/course-progress.read-module.ts b/packages/api/src/module/read/course-progress/course-progress.read-module.ts
index 3f62bcf1..1a30fc12 100644
--- a/packages/api/src/module/read/course-progress/course-progress.read-module.ts
+++ b/packages/api/src/module/read/course-progress/course-progress.read-module.ts
@@ -18,44 +18,48 @@ export class CourseProgressReadModule {
   constructor(private readonly prismaService: PrismaService) {}
 
   @OnEvent('LearningMaterialsUrl.LearningMaterialsUrlWasGenerated')
-  async onLearningResourcesUrlWasGenerated(event: ApplicationEvent<LearningMaterialsUrlWasGenerated>) {
-    await this.prismaService.courseProgress.create({
-      data: {
-        courseUserId: event.data.courseUserId,
-        learningMaterialsId: event.data.learningMaterialsId,
-        learningMaterialsCompletedTasks: 0,
-      },
+  async onLearningResourcesUrlWasGenerated({
+    data: { learningMaterialsId, courseUserId },
+  }: ApplicationEvent<LearningMaterialsUrlWasGenerated>) {
+    await this.prismaService.courseProgress.upsert({
+      where: { learningMaterialsId },
+      create: { learningMaterialsId, learningMaterialsCompletedTasks: 0, courseUserId },
+      update: { courseUserId },
     });
   }
 
   @OnEvent('LearningMaterialsTasks.TaskWasUncompleted')
-  async onTaskWasUncompleted(event: ApplicationEvent<TaskWasUncompleted>) {
-    const where = { learningMaterialsId: event.data.learningMaterialsId };
-    const courseProgress = await this.prismaService.courseProgress.findUnique({ where });
-
-    if (!courseProgress || courseProgress.learningMaterialsCompletedTasks === 0) {
-      return;
-    }
-
-    await this.prismaService.courseProgress.update({
-      where,
-      data: {
-        learningMaterialsCompletedTasks: { decrement: 1 },
-      },
-    });
+  async onTaskWasUncompleted({ data: { learningMaterialsId } }: ApplicationEvent<TaskWasUncompleted>) {
+    await this.prismaService.courseProgress.upsert(
+      this.courseProgressStateUpdated({ learningMaterialsId, completedTasks: 'decrement' }),
+    );
   }
 
   @OnEvent('LearningMaterialsTasks.TaskWasCompleted')
-  async onTaskWasCompleted(event: ApplicationEvent<TaskWasCompleted>) {
-    await this.prismaService.courseProgress.update({
-      where: {
-        learningMaterialsId: event.data.learningMaterialsId,
-      },
-      data: {
+  async onTaskWasCompleted({ data: { learningMaterialsId } }: ApplicationEvent<TaskWasCompleted>) {
+    await this.prismaService.courseProgress.upsert(
+      this.courseProgressStateUpdated({ learningMaterialsId, completedTasks: 'increment' }),
+    );
+  }
+
+  private courseProgressStateUpdated({
+    learningMaterialsId,
+    completedTasks,
+  }: {
+    learningMaterialsId: string;
+    completedTasks: 'increment' | 'decrement';
+  }) {
+    return {
+      where: { learningMaterialsId },
+      update: {
         learningMaterialsCompletedTasks: {
-          increment: 1,
+          [completedTasks]: 1,
         },
       },
-    });
+      create: {
+        learningMaterialsId,
+        learningMaterialsCompletedTasks: completedTasks === 'increment' ? 1 : 0,
+      },
+    };
   }
 }
diff --git a/packages/api/src/module/shared/commands/complete-task.application-command.ts b/packages/api/src/module/shared/commands/complete-task.application-command.ts
new file mode 100644
index 00000000..7f91f7a6
--- /dev/null
+++ b/packages/api/src/module/shared/commands/complete-task.application-command.ts
@@ -0,0 +1,5 @@
+import { AbstractApplicationCommand } from '@/module/application-command-events';
+
+import { CompleteTask } from './complete-task.domain-command';
+
+export class CompleteTaskApplicationCommand extends AbstractApplicationCommand<CompleteTask> {}
diff --git a/packages/api/src/module/shared/commands/complete-task.domain-command.ts b/packages/api/src/module/shared/commands/complete-task.domain-command.ts
new file mode 100644
index 00000000..cecacf33
--- /dev/null
+++ b/packages/api/src/module/shared/commands/complete-task.domain-command.ts
@@ -0,0 +1,4 @@
+export type CompleteTask = {
+  type: 'CompleteTask';
+  data: { learningMaterialsId: string; taskId: string };
+};
diff --git a/packages/api/src/module/write/learning-materials-tasks/application/complete-task.command-handler.ts b/packages/api/src/module/write/learning-materials-tasks/application/complete-task.command-handler.ts
new file mode 100644
index 00000000..3bf718c2
--- /dev/null
+++ b/packages/api/src/module/write/learning-materials-tasks/application/complete-task.command-handler.ts
@@ -0,0 +1,30 @@
+import { Inject } from '@nestjs/common';
+import { CommandHandler, ICommandHandler } from '@nestjs/cqrs';
+
+import { CompleteTaskApplicationCommand } from '@/commands/complete-task.application-command';
+import { TaskWasCompleted } from '@/module/events/task-was-completed.domain-event';
+import { APPLICATION_SERVICE, ApplicationService } from '@/write/shared/application/application-service';
+import { EventStreamName } from '@/write/shared/application/event-stream-name.value-object';
+
+import { completeTask } from '../domain/complete-task';
+
+@CommandHandler(CompleteTaskApplicationCommand)
+export class CompleteTaskCommandHandler implements ICommandHandler<CompleteTaskApplicationCommand> {
+  constructor(
+    @Inject(APPLICATION_SERVICE)
+    private readonly applicationService: ApplicationService,
+  ) {}
+
+  async execute(command: CompleteTaskApplicationCommand): Promise<void> {
+    const eventStream = EventStreamName.from('LearningMaterialsTasks', command.data.learningMaterialsId);
+
+    await this.applicationService.execute<TaskWasCompleted>(
+      eventStream,
+      {
+        causationId: command.id,
+        correlationId: command.metadata.correlationId,
+      },
+      (pastEvents) => completeTask(pastEvents, command),
+    );
+  }
+}
diff --git a/packages/api/src/module/write/learning-materials-tasks/domain/complete-task.spec.ts b/packages/api/src/module/write/learning-materials-tasks/domain/complete-task.spec.ts
new file mode 100644
index 00000000..f9e2e2fe
--- /dev/null
+++ b/packages/api/src/module/write/learning-materials-tasks/domain/complete-task.spec.ts
@@ -0,0 +1,64 @@
+import { CompleteTask } from '@/module/commands/complete-task.domain-command';
+import { TaskWasCompleted } from '@/module/events/task-was-completed.domain-event';
+
+import { completeTask } from './complete-task';
+
+describe('complete task', () => {
+  const command: CompleteTask = {
+    type: 'CompleteTask',
+    data: { learningMaterialsId: 'sbAPITNMsl2wW6j2cg1H2A', taskId: 'L9EXtwmBNBXgo_qh0uzbq' },
+  };
+
+  it('should return task was completed', () => {
+    // Given
+    const pastEvents: TaskWasCompleted[] = [];
+
+    // When
+    const events = completeTask(pastEvents, command);
+
+    // Then
+    expect(events).toStrictEqual([
+      {
+        type: 'TaskWasCompleted',
+        data: { learningMaterialsId: command.data.learningMaterialsId, taskId: command.data.taskId },
+      },
+    ]);
+  });
+
+  it('should return task was completed if other tasks are completed', () => {
+    // Given
+    const pastEvents: TaskWasCompleted[] = [
+      {
+        type: 'TaskWasCompleted',
+        data: { learningMaterialsId: command.data.learningMaterialsId, taskId: 'BIt23CR3dLKkHn_a2IM4V' },
+      },
+    ];
+
+    // When
+    const events = completeTask(pastEvents, command);
+
+    // Then
+    expect(events).toStrictEqual([
+      {
+        type: 'TaskWasCompleted',
+        data: { learningMaterialsId: command.data.learningMaterialsId, taskId: command.data.taskId },
+      },
+    ]);
+  });
+
+  it('should throw exception if task was already completed', () => {
+    // Given
+    const pastEvents: TaskWasCompleted[] = [
+      {
+        type: 'TaskWasCompleted',
+        data: { learningMaterialsId: command.data.learningMaterialsId, taskId: command.data.taskId },
+      },
+    ];
+
+    // When
+    const events = () => completeTask(pastEvents, command);
+
+    // Then
+    expect(events).toThrowError('Task was already completed');
+  });
+});
diff --git a/packages/api/src/module/write/learning-materials-tasks/domain/complete-task.ts b/packages/api/src/module/write/learning-materials-tasks/domain/complete-task.ts
new file mode 100644
index 00000000..0d03642b
--- /dev/null
+++ b/packages/api/src/module/write/learning-materials-tasks/domain/complete-task.ts
@@ -0,0 +1,37 @@
+import { TaskWasCompleted } from '@/events/task-was-completed.domain-event';
+import { CompleteTask } from '@/module/commands/complete-task.domain-command';
+
+export function completeTask(
+  pastEvents: TaskWasCompleted[],
+  { data: { learningMaterialsId, taskId } }: CompleteTask,
+): TaskWasCompleted[] {
+  const state = pastEvents
+    .filter(({ data }) => data.taskId === taskId)
+    .reduce<{ completed: boolean }>(
+      (acc, event) => {
+        switch (event.type) {
+          case 'TaskWasCompleted': {
+            return { completed: true };
+          }
+          default: {
+            return acc;
+          }
+        }
+      },
+      { completed: false },
+    );
+
+  if (state.completed) {
+    throw new Error('Task was already completed');
+  }
+
+  const newEvent: TaskWasCompleted = {
+    type: 'TaskWasCompleted',
+    data: {
+      taskId,
+      learningMaterialsId,
+    },
+  };
+
+  return [newEvent];
+}
diff --git a/packages/api/src/module/write/learning-materials-tasks/learning-materials-tasks.test-module.ts b/packages/api/src/module/write/learning-materials-tasks/learning-materials-tasks.test-module.ts
new file mode 100644
index 00000000..40621bdb
--- /dev/null
+++ b/packages/api/src/module/write/learning-materials-tasks/learning-materials-tasks.test-module.ts
@@ -0,0 +1,5 @@
+import { initWriteTestModule } from '@/shared/test-utils';
+
+export async function learningMaterialsTasksTestModule() {
+  return initWriteTestModule();
+}
diff --git a/packages/api/src/module/write/learning-materials-tasks/learning-materials-tasks.write-module.spec.ts b/packages/api/src/module/write/learning-materials-tasks/learning-materials-tasks.write-module.spec.ts
new file mode 100644
index 00000000..72ba47df
--- /dev/null
+++ b/packages/api/src/module/write/learning-materials-tasks/learning-materials-tasks.write-module.spec.ts
@@ -0,0 +1,53 @@
+import { AsyncReturnType } from 'type-fest';
+
+import { CompleteTaskApplicationCommand } from '@/module/commands/complete-task.application-command';
+import { TaskWasCompleted } from '@/module/events/task-was-completed.domain-event';
+
+import { EventStreamName } from '../shared/application/event-stream-name.value-object';
+import { learningMaterialsTasksTestModule } from './learning-materials-tasks.test-module';
+
+describe('learning materials tasks', () => {
+  let module: AsyncReturnType<typeof learningMaterialsTasksTestModule>;
+  const commandBuilder = (taskId = 'VmkxXnPG02CaUNV8Relzk', learningMaterialsId = 'ZpMpw2eh1llFCGKZJEN6r') => ({
+    class: CompleteTaskApplicationCommand,
+    type: 'CompleteTask',
+    data: { taskId, learningMaterialsId },
+  });
+
+  it('should change state of the task to complete', async () => {
+    // Given
+    const command = commandBuilder();
+
+    // When
+    await module.executeCommand(() => command);
+
+    // Then
+    await module.expectEventPublishedLastly<TaskWasCompleted>({
+      type: 'TaskWasCompleted',
+      data: {
+        learningMaterialsId: command.data.learningMaterialsId,
+        taskId: command.data.taskId,
+      },
+      streamName: EventStreamName.from('LearningMaterialsTasks', command.data.learningMaterialsId),
+    });
+  });
+
+  it('should not change task state if task is already completed', async () => {
+    // Given
+    const command = commandBuilder();
+
+    // When
+    await module.executeCommand(() => command);
+
+    // Then
+    await expect(() => module.executeCommand(() => command)).rejects.toThrow();
+  });
+
+  beforeEach(async () => {
+    module = await learningMaterialsTasksTestModule();
+  });
+
+  afterEach(async () => {
+    await module.close();
+  });
+});
diff --git a/packages/api/src/module/write/learning-materials-tasks/learning-materials-tasks.write-module.ts b/packages/api/src/module/write/learning-materials-tasks/learning-materials-tasks.write-module.ts
new file mode 100644
index 00000000..acdd9c64
--- /dev/null
+++ b/packages/api/src/module/write/learning-materials-tasks/learning-materials-tasks.write-module.ts
@@ -0,0 +1,12 @@
+import { Module } from '@nestjs/common';
+
+import { SharedModule } from '../shared/shared.module';
+import { CompleteTaskCommandHandler } from './application/complete-task.command-handler';
+import { LearningMaterialsTaskRestController } from './presentation/rest/process-st-events.rest-controller';
+
+@Module({
+  imports: [SharedModule],
+  providers: [CompleteTaskCommandHandler],
+  controllers: [LearningMaterialsTaskRestController],
+})
+export class LearningMaterialsTasksModule {}
diff --git a/packages/api/src/module/write/learning-materials-tasks/presentation/rest/process-st-events.rest-controller.ts b/packages/api/src/module/write/learning-materials-tasks/presentation/rest/process-st-events.rest-controller.ts
new file mode 100644
index 00000000..14502097
--- /dev/null
+++ b/packages/api/src/module/write/learning-materials-tasks/presentation/rest/process-st-events.rest-controller.ts
@@ -0,0 +1,28 @@
+import { Body, Controller, HttpCode, Post } from '@nestjs/common';
+import { CommandBus } from '@nestjs/cqrs';
+
+import { CompleteTaskApplicationCommand } from '@/module/commands/complete-task.application-command';
+import { ApplicationCommandFactory } from '@/write/shared/application/application-command.factory';
+
+import { TaskCompletedRequestBody } from '../../types/taskCompletedRequestBody';
+
+@Controller('process-st/events')
+export class LearningMaterialsTaskRestController {
+  constructor(private readonly commandBus: CommandBus, private readonly commandFactory: ApplicationCommandFactory) {}
+
+  @Post('task-checked-unchecked')
+  @HttpCode(200)
+  async taskCheckedUnchecked(
+    @Body() { id: learningMaterialsId, data: { id: taskId, status } }: TaskCompletedRequestBody,
+  ): Promise<void> {
+    if (status === 'Completed') {
+      const command = this.commandFactory.applicationCommand(() => ({
+        class: CompleteTaskApplicationCommand,
+        type: 'CompleteTask',
+        data: { learningMaterialsId, taskId },
+      }));
+
+      await this.commandBus.execute(command);
+    }
+  }
+}
diff --git a/packages/api/src/module/write/learning-materials-tasks/types/taskCompletedRequestBody.ts b/packages/api/src/module/write/learning-materials-tasks/types/taskCompletedRequestBody.ts
new file mode 100644
index 00000000..13c4575c
--- /dev/null
+++ b/packages/api/src/module/write/learning-materials-tasks/types/taskCompletedRequestBody.ts
@@ -0,0 +1,12 @@
+export interface TaskCompletedRequestBody {
+  id: string;
+  createdDate: string;
+  data: {
+    id: string;
+    status: string;
+    stopped: boolean;
+    hidden: boolean;
+    name: string;
+  };
+  type: string;
+}