diff --git a/src/main/java/ru/practicum/shareit/booking/Booking.java b/src/main/java/ru/practicum/shareit/booking/Booking.java
index 2d9c666..d76494a 100644
--- a/src/main/java/ru/practicum/shareit/booking/Booking.java
+++ b/src/main/java/ru/practicum/shareit/booking/Booking.java
@@ -1,7 +1,28 @@
 package ru.practicum.shareit.booking;
 
+import lombok.Data;
+import ru.practicum.shareit.item.model.Item;
+import ru.practicum.shareit.user.model.User;
+
+import java.time.LocalDateTime;
+
 /**
  * TODO Sprint add-bookings.
  */
+@Data
 public class Booking {
+    private Long id;
+    private LocalDateTime start;
+    private LocalDateTime end;
+    private Item item;
+    private User booker;
+    private Status status;
+
+    enum Status {
+        WAITING,
+        APPROVED,
+        REJECTED,
+        CANCELED
+    }
+
 }
diff --git a/src/main/java/ru/practicum/shareit/exception/AlreadyExistException.java b/src/main/java/ru/practicum/shareit/exception/AlreadyExistException.java
new file mode 100644
index 0000000..5378b90
--- /dev/null
+++ b/src/main/java/ru/practicum/shareit/exception/AlreadyExistException.java
@@ -0,0 +1,7 @@
+package ru.practicum.shareit.exception;
+
+public class AlreadyExistException extends RuntimeException {
+  public AlreadyExistException(String message) {
+    super(message);
+  }
+}
diff --git a/src/main/java/ru/practicum/shareit/exception/ErrorHandler.java b/src/main/java/ru/practicum/shareit/exception/ErrorHandler.java
new file mode 100644
index 0000000..000fbff
--- /dev/null
+++ b/src/main/java/ru/practicum/shareit/exception/ErrorHandler.java
@@ -0,0 +1,41 @@
+package ru.practicum.shareit.exception;
+
+import lombok.extern.slf4j.Slf4j;
+import org.springframework.http.HttpStatus;
+import org.springframework.web.bind.MethodArgumentNotValidException;
+import org.springframework.web.bind.annotation.ExceptionHandler;
+import org.springframework.web.bind.annotation.ResponseStatus;
+import org.springframework.web.bind.annotation.RestControllerAdvice;
+
+@Slf4j
+@RestControllerAdvice
+public class ErrorHandler {
+
+    @ExceptionHandler
+    @ResponseStatus(HttpStatus.BAD_REQUEST)
+    public ErrorResponse handleValidationException(MethodArgumentNotValidException e) {
+        log.debug(e.getBindingResult().getAllErrors().getFirst().getDefaultMessage(), e);
+        return new ErrorResponse(HttpStatus.BAD_REQUEST.value(), e.getBindingResult().getAllErrors().getFirst().getDefaultMessage());
+    }
+
+    @ExceptionHandler
+    @ResponseStatus(HttpStatus.NOT_FOUND)
+    public ErrorResponse handleValidationException(NotFoundException e) {
+        log.debug(e.getMessage(), e);
+        return new ErrorResponse(HttpStatus.BAD_REQUEST.value(), e.getMessage());
+    }
+
+    @ExceptionHandler
+    @ResponseStatus(HttpStatus.CONFLICT)
+    public ErrorResponse handleValidationException(AlreadyExistException e) {
+        log.debug(e.getMessage(), e);
+        return new ErrorResponse(HttpStatus.BAD_REQUEST.value(), e.getMessage());
+    }
+
+    @ExceptionHandler
+    @ResponseStatus(HttpStatus.FORBIDDEN)
+    public ErrorResponse handleValidationException(NotAccessException e) {
+        log.debug(e.getMessage(), e);
+        return new ErrorResponse(HttpStatus.FORBIDDEN.value(), e.getMessage());
+    }
+}
diff --git a/src/main/java/ru/practicum/shareit/exception/ErrorResponse.java b/src/main/java/ru/practicum/shareit/exception/ErrorResponse.java
new file mode 100644
index 0000000..d10218a
--- /dev/null
+++ b/src/main/java/ru/practicum/shareit/exception/ErrorResponse.java
@@ -0,0 +1,11 @@
+package ru.practicum.shareit.exception;
+
+import lombok.AllArgsConstructor;
+import lombok.Data;
+
+@Data
+@AllArgsConstructor
+public class ErrorResponse {
+    private Integer statusCode;
+    private String error;
+}
diff --git a/src/main/java/ru/practicum/shareit/exception/NotAccessException.java b/src/main/java/ru/practicum/shareit/exception/NotAccessException.java
new file mode 100644
index 0000000..0c0873b
--- /dev/null
+++ b/src/main/java/ru/practicum/shareit/exception/NotAccessException.java
@@ -0,0 +1,7 @@
+package ru.practicum.shareit.exception;
+
+public class NotAccessException extends RuntimeException {
+    public NotAccessException(String message) {
+        super(message);
+    }
+}
diff --git a/src/main/java/ru/practicum/shareit/exception/NotFoundException.java b/src/main/java/ru/practicum/shareit/exception/NotFoundException.java
new file mode 100644
index 0000000..508b545
--- /dev/null
+++ b/src/main/java/ru/practicum/shareit/exception/NotFoundException.java
@@ -0,0 +1,7 @@
+package ru.practicum.shareit.exception;
+
+public class NotFoundException extends RuntimeException {
+    public NotFoundException(String message) {
+        super(message);
+    }
+}
diff --git a/src/main/java/ru/practicum/shareit/item/ItemController.java b/src/main/java/ru/practicum/shareit/item/ItemController.java
index bb17668..af398c8 100644
--- a/src/main/java/ru/practicum/shareit/item/ItemController.java
+++ b/src/main/java/ru/practicum/shareit/item/ItemController.java
@@ -1,12 +1,47 @@
 package ru.practicum.shareit.item;
 
-import org.springframework.web.bind.annotation.RequestMapping;
-import org.springframework.web.bind.annotation.RestController;
+import jakarta.validation.Valid;
+import lombok.AllArgsConstructor;
+import org.springframework.web.bind.annotation.*;
+import ru.practicum.shareit.item.dto.ItemDto;
+import ru.practicum.shareit.item.service.ItemService;
+
+import java.util.List;
 
-/**
- * TODO Sprint add-controllers.
- */
 @RestController
+@AllArgsConstructor
 @RequestMapping("/items")
 public class ItemController {
+
+    private final ItemService itemService;
+
+    @GetMapping
+    public List<ItemDto> getItemsByUserId(@RequestHeader("X-Sharer-User-Id") Long userId) {
+        return itemService.getItemsByUserId(userId);
+    }
+
+    @GetMapping("/{itemId}")
+    public ItemDto getItemById(@PathVariable Long itemId) {
+        return itemService.getItemById(itemId);
+    }
+
+    @PostMapping
+    public ItemDto createItem(
+            @Valid @RequestBody ItemDto itemDto,
+            @RequestHeader("X-Sharer-User-Id") Long userId) {
+        return itemService.createItem(itemDto, userId);
+    }
+
+    @PatchMapping("/{itemId}")
+    public ItemDto updateItem(
+            @RequestBody ItemDto itemDto,
+            @PathVariable Long itemId,
+            @RequestHeader("X-Sharer-User-Id") Long userId) {
+        return itemService.updateItem(itemDto, itemId, userId);
+    }
+
+    @GetMapping("/search")
+    public List<ItemDto> getItemsSearchByText(@RequestParam String text) {
+        return itemService.searchItemsByText(text);
+    }
 }
diff --git a/src/main/java/ru/practicum/shareit/item/dto/ItemDto.java b/src/main/java/ru/practicum/shareit/item/dto/ItemDto.java
index 9319d7d..1b82a99 100644
--- a/src/main/java/ru/practicum/shareit/item/dto/ItemDto.java
+++ b/src/main/java/ru/practicum/shareit/item/dto/ItemDto.java
@@ -1,7 +1,19 @@
 package ru.practicum.shareit.item.dto;
 
-/**
- * TODO Sprint add-controllers.
- */
+import jakarta.validation.constraints.NotBlank;
+import jakarta.validation.constraints.NotNull;
+import lombok.AllArgsConstructor;
+import lombok.Data;
+
+@Data
+@AllArgsConstructor
 public class ItemDto {
+    private Long id;
+    @NotBlank(message = "Название не может быть пустым")
+    private String name;
+    @NotBlank(message = "Описание не может быть пустым")
+    private String description;
+    @NotNull(message = "Статус о доступности не может быть пустым")
+    private Boolean available;
+    private Long requestId;
 }
diff --git a/src/main/java/ru/practicum/shareit/item/mapper/ItemMapper.java b/src/main/java/ru/practicum/shareit/item/mapper/ItemMapper.java
new file mode 100644
index 0000000..76264bf
--- /dev/null
+++ b/src/main/java/ru/practicum/shareit/item/mapper/ItemMapper.java
@@ -0,0 +1,30 @@
+package ru.practicum.shareit.item.mapper;
+
+import ru.practicum.shareit.item.dto.ItemDto;
+import ru.practicum.shareit.item.model.Item;
+import ru.practicum.shareit.request.ItemRequest;
+import ru.practicum.shareit.user.model.User;
+
+public class ItemMapper {
+
+    public static ItemDto toItemDto(Item item) {
+        return new ItemDto(
+                item.getId(),
+                item.getName(),
+                item.getDescription(),
+                item.getAvailable(),
+                item.getRequest() != null ? item.getRequest().getId() : null
+        );
+    }
+
+    public static Item toItem(ItemDto itemDto, User owner, ItemRequest request) {
+        return new Item(
+                itemDto.getName(),
+                itemDto.getDescription(),
+                itemDto.getAvailable(),
+                owner,
+                request
+        );
+    }
+
+}
diff --git a/src/main/java/ru/practicum/shareit/item/model/Item.java b/src/main/java/ru/practicum/shareit/item/model/Item.java
index 44eb73d..69e581b 100644
--- a/src/main/java/ru/practicum/shareit/item/model/Item.java
+++ b/src/main/java/ru/practicum/shareit/item/model/Item.java
@@ -1,7 +1,26 @@
 package ru.practicum.shareit.item.model;
 
-/**
- * TODO Sprint add-controllers.
- */
+
+import lombok.AllArgsConstructor;
+import lombok.Data;
+import ru.practicum.shareit.request.ItemRequest;
+import ru.practicum.shareit.user.model.User;
+
+@Data
+@AllArgsConstructor
 public class Item {
+    private Long id;
+    private String name;
+    private String description;
+    private Boolean available;
+    private User owner;
+    private ItemRequest request;
+
+    public Item(String name, String description, Boolean available, User owner, ItemRequest request) {
+        this.name = name;
+        this.description = description;
+        this.available = available;
+        this.owner = owner;
+        this.request = request;
+    }
 }
diff --git a/src/main/java/ru/practicum/shareit/item/repository/ItemRepository.java b/src/main/java/ru/practicum/shareit/item/repository/ItemRepository.java
new file mode 100644
index 0000000..73c780d
--- /dev/null
+++ b/src/main/java/ru/practicum/shareit/item/repository/ItemRepository.java
@@ -0,0 +1,20 @@
+package ru.practicum.shareit.item.repository;
+
+import ru.practicum.shareit.item.model.Item;
+
+import java.util.List;
+import java.util.Optional;
+
+public interface ItemRepository {
+
+    List<Item> getItemsByUserId(Long userId);
+
+    Item createItem(Item item);
+
+    Item updateItem(Item item);
+
+    Optional<Item> getItemById(Long itemId);
+
+    List<Item> searchItemsByText(String text);
+
+}
diff --git a/src/main/java/ru/practicum/shareit/item/repository/ItemRepositoryImpl.java b/src/main/java/ru/practicum/shareit/item/repository/ItemRepositoryImpl.java
new file mode 100644
index 0000000..297c005
--- /dev/null
+++ b/src/main/java/ru/practicum/shareit/item/repository/ItemRepositoryImpl.java
@@ -0,0 +1,55 @@
+package ru.practicum.shareit.item.repository;
+
+import org.springframework.stereotype.Repository;
+import ru.practicum.shareit.item.model.Item;
+
+import java.util.*;
+
+@Repository
+public class ItemRepositoryImpl implements ItemRepository {
+
+    private final Map<Long, Item> items = new HashMap<>();
+
+    @Override
+    public List<Item> getItemsByUserId(Long userId) {
+        return items.values().stream()
+                .filter(item -> Objects.equals(item.getOwner().getId(), userId))
+                .toList();
+    }
+
+    @Override
+    public Item createItem(Item item) {
+        item.setId(getNewItemId());
+        items.put(item.getId(), item);
+        return items.get(item.getId());
+    }
+
+    @Override
+    public Item updateItem(Item item) {
+        items.put(item.getId(), item);
+        return items.get(item.getId());
+    }
+
+    @Override
+    public Optional<Item> getItemById(Long itemId) {
+        return Optional.ofNullable(items.get(itemId));
+    }
+
+    @Override
+    public List<Item> searchItemsByText(String text) {
+        return items.values().stream()
+                .filter(item -> (containsIgnoreCase(item.getName(), text) ||
+                        containsIgnoreCase(item.getDescription(), text)) && item.getAvailable())
+                .toList();
+    }
+
+    private Boolean containsIgnoreCase(String text, String containsText) {
+        return text.toLowerCase().contains(containsText.toLowerCase());
+    }
+
+    private Long getNewItemId() {
+        return items.keySet().stream()
+                .max(Long::compareTo)
+                .orElse(0L) + 1;
+    }
+}
diff --git a/src/main/java/ru/practicum/shareit/item/service/ItemService.java b/src/main/java/ru/practicum/shareit/item/service/ItemService.java
new file mode 100644
index 0000000..f76170f
--- /dev/null
+++ b/src/main/java/ru/practicum/shareit/item/service/ItemService.java
@@ -0,0 +1,17 @@
+package ru.practicum.shareit.item.service;
+
+import ru.practicum.shareit.item.dto.ItemDto;
+
+import java.util.List;
+
+public interface ItemService {
+    List<ItemDto> getItemsByUserId(Long userId);
+
+    ItemDto createItem(ItemDto itemDto, Long userId);
+
+    ItemDto updateItem(ItemDto itemDto, Long itemId, Long userId);
+
+    ItemDto getItemById(Long itemId);
+
+    List<ItemDto> searchItemsByText(String text);
+}
diff --git a/src/main/java/ru/practicum/shareit/item/service/ItemServiceImpl.java b/src/main/java/ru/practicum/shareit/item/service/ItemServiceImpl.java
new file mode 100644
index 0000000..95ddca5
--- /dev/null
+++ b/src/main/java/ru/practicum/shareit/item/service/ItemServiceImpl.java
@@ -0,0 +1,93 @@
+package ru.practicum.shareit.item.service;
+
+import lombok.AllArgsConstructor;
+import lombok.extern.slf4j.Slf4j;
+import org.springframework.stereotype.Service;
+import ru.practicum.shareit.exception.NotAccessException;
+import ru.practicum.shareit.exception.NotFoundException;
+import ru.practicum.shareit.item.dto.ItemDto;
+import ru.practicum.shareit.item.mapper.ItemMapper;
+import ru.practicum.shareit.item.model.Item;
+import ru.practicum.shareit.item.repository.ItemRepository;
+import ru.practicum.shareit.user.model.User;
+import ru.practicum.shareit.user.service.UserService;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Objects;
+
+@Slf4j
+@Service
+@AllArgsConstructor
+public class ItemServiceImpl implements ItemService {
+
+    private final ItemRepository itemRepository;
+    private final UserService userService;
+
+
+    @Override
+    public List<ItemDto> getItemsByUserId(Long userId) {
+        log.info("Поиск вещей пользователя с ID = {}", userId);
+        userService.getUserWithCheck(userId);
+        List<Item> itemsByUserId = itemRepository.getItemsByUserId(userId);
+        return itemsByUserId.stream()
+                .map(ItemMapper::toItemDto)
+                .toList();
+    }
+
+    public Item getItemWithCheck(Long itemId) {
+        return itemRepository.getItemById(itemId)
+                .orElseThrow(() -> new NotFoundException("Вещь с ID = " + itemId + " не найдена"));
+    }
+
+    @Override
+    public ItemDto createItem(ItemDto itemDto, Long userId) {
+        log.info("Создание вещи у пользователя с ID = {}", userId);
+        User user = userService.getUserWithCheck(userId);
+        return ItemMapper.toItemDto(
+                itemRepository.createItem(
+                        ItemMapper.toItem(itemDto, user, null)));
+    }
+
+    @Override
+    public ItemDto updateItem(ItemDto itemDto, Long itemId, Long userId) {
+        log.info("Обновление вещи у пользователя с ID = {}", userId);
+
+        Item findItem = getItemWithCheck(itemId);
+        checkUser(findItem, userId);
+        userService.getUserWithCheck(userId);
+
+        findItem.setName(itemDto.getName() == null || itemDto.getName().isBlank() ?
+                findItem.getName() : itemDto.getName());
+        findItem.setDescription(itemDto.getDescription() == null || itemDto.getDescription().isBlank() ?
+                findItem.getDescription() : itemDto.getDescription());
+        findItem.setAvailable(itemDto.getAvailable() != null ? itemDto.getAvailable() : findItem.getAvailable());
+
+        return ItemMapper.toItemDto(itemRepository.updateItem(findItem));
+    }
+
+    @Override
+    public ItemDto getItemById(Long itemId) {
+        log.info("Запрос вещи с ID = {}", itemId);
+        Item item = getItemWithCheck(itemId);
+        return ItemMapper.toItemDto(item);
+    }
+
+    @Override
+    public List<ItemDto> searchItemsByText(String text) {
+        log.info("Поиск вещей по тексту \"{}\"", text);
+        if (text.isBlank()) {
+            return new ArrayList<>();
+        }
+        return itemRepository.searchItemsByText(text).stream()
+                .map(ItemMapper::toItemDto)
+                .toList();
+    }
+
+    private void checkUser(Item item, Long userIdFromRequest) {
+        if (!Objects.equals(item.getOwner().getId(), userIdFromRequest)) {
+            throw new NotAccessException("Вещь с ID = " + item.getId() + " не принадлежит пользователю с ID = " + userIdFromRequest);
+        }
+    }
+
+}
diff --git a/src/main/java/ru/practicum/shareit/request/ItemRequest.java b/src/main/java/ru/practicum/shareit/request/ItemRequest.java
index 95d6f23..decd8a3 100644
--- a/src/main/java/ru/practicum/shareit/request/ItemRequest.java
+++ b/src/main/java/ru/practicum/shareit/request/ItemRequest.java
@@ -1,7 +1,17 @@
 package ru.practicum.shareit.request;
 
+import lombok.Data;
+import ru.practicum.shareit.user.model.User;
+
+import java.time.LocalDateTime;
+
 /**
  * TODO Sprint add-item-requests.
  */
+@Data
 public class ItemRequest {
+    private Long id;
+    private String description;
+    private User requestor;
+    private LocalDateTime created;
 }
diff --git a/src/main/java/ru/practicum/shareit/user/User.java b/src/main/java/ru/practicum/shareit/user/User.java
deleted file mode 100644
index ae6e7f3..0000000
--- a/src/main/java/ru/practicum/shareit/user/User.java
+++ /dev/null
@@ -1,7 +0,0 @@
-package ru.practicum.shareit.user;
-
-/**
- * TODO Sprint add-controllers.
- */
-public class User {
-}
diff --git a/src/main/java/ru/practicum/shareit/user/UserController.java b/src/main/java/ru/practicum/shareit/user/UserController.java
index 03039b9..421d352 100644
--- a/src/main/java/ru/practicum/shareit/user/UserController.java
+++ b/src/main/java/ru/practicum/shareit/user/UserController.java
@@ -1,12 +1,35 @@
 package ru.practicum.shareit.user;
 
-import org.springframework.web.bind.annotation.RequestMapping;
-import org.springframework.web.bind.annotation.RestController;
+import jakarta.validation.Valid;
+import lombok.AllArgsConstructor;
+import org.springframework.web.bind.annotation.*;
+import ru.practicum.shareit.user.dto.UserDto;
+import ru.practicum.shareit.user.service.UserService;
 
-/**
- * TODO Sprint add-controllers.
- */
 @RestController
+@AllArgsConstructor
 @RequestMapping(path = "/users")
 public class UserController {
+
+    private final UserService userService;
+
+    @GetMapping("/{userId}")
+    public UserDto getUserById(@PathVariable Long userId) {
+        return userService.getUserById(userId);
+    }
+
+    @PostMapping
+    public UserDto createUser(@Valid @RequestBody UserDto userDto) {
+        return userService.createUser(userDto);
+    }
+
+    @PatchMapping("/{userId}")
+    public UserDto updateUser(@RequestBody UserDto userDto, @PathVariable Long userId) {
+        return userService.updateUser(userDto, userId);
+    }
+
+    @DeleteMapping("/{userId}")
+    public void deleteUser(@PathVariable Long userId) {
+        userService.deleteUserById(userId);
+    }
 }
diff --git a/src/main/java/ru/practicum/shareit/user/dto/UserDto.java b/src/main/java/ru/practicum/shareit/user/dto/UserDto.java
new file mode 100644
index 0000000..b94bd2e
--- /dev/null
+++ b/src/main/java/ru/practicum/shareit/user/dto/UserDto.java
@@ -0,0 +1,18 @@
+package ru.practicum.shareit.user.dto;
+
+import jakarta.validation.constraints.Email;
+import jakarta.validation.constraints.NotBlank;
+import jakarta.validation.constraints.NotNull;
+import lombok.AllArgsConstructor;
+import lombok.Data;
+
+@Data
+@AllArgsConstructor
+public class UserDto {
+    private Long id;
+    @NotNull(message = "Имя не может быть пустым")
+    private String name;
+    @NotBlank(message = "Почта не может быть пустой")
+    @Email(message = "Некорректный email")
+    private String email;
+}
diff --git a/src/main/java/ru/practicum/shareit/user/mapper/UserMapper.java b/src/main/java/ru/practicum/shareit/user/mapper/UserMapper.java
new file mode 100644
index 0000000..b1350ed
--- /dev/null
+++ b/src/main/java/ru/practicum/shareit/user/mapper/UserMapper.java
@@ -0,0 +1,21 @@
+package ru.practicum.shareit.user.mapper;
+
+import ru.practicum.shareit.user.dto.UserDto;
+import ru.practicum.shareit.user.model.User;
+
+public class UserMapper {
+    public static UserDto toUserDto(User user) {
+        return new UserDto(
+                user.getId(),
+                user.getName(),
+                user.getEmail()
+        );
+    }
+
+    public static User toUser(UserDto user) {
+        return new User(
+                user.getName(),
+                user.getEmail()
+        );
+    }
+}
diff --git a/src/main/java/ru/practicum/shareit/user/model/User.java b/src/main/java/ru/practicum/shareit/user/model/User.java
new file mode 100644
index 0000000..c3779e3
--- /dev/null
+++ b/src/main/java/ru/practicum/shareit/user/model/User.java
@@ -0,0 +1,17 @@
+package ru.practicum.shareit.user.model;
+
+import lombok.AllArgsConstructor;
+import lombok.Data;
+
+@Data
+@AllArgsConstructor
+public class User {
+    private Long id;
+    private String name;
+    private String email;
+
+    public User(String name, String email) {
+        this.name = name;
+        this.email = email;
+    }
+}
diff --git a/src/main/java/ru/practicum/shareit/user/repository/UserRepository.java b/src/main/java/ru/practicum/shareit/user/repository/UserRepository.java
new file mode 100644
index 0000000..820e66f
--- /dev/null
+++ b/src/main/java/ru/practicum/shareit/user/repository/UserRepository.java
@@ -0,0 +1,21 @@
+package ru.practicum.shareit.user.repository;
+
+import ru.practicum.shareit.user.model.User;
+
+import java.util.List;
+import java.util.Optional;
+
+public interface UserRepository {
+
+    List<User> getUsers();
+
+    Optional<User> getUserById(Long userId);
+
+    User createUser(User user);
+
+    User updateUser(User user);
+
+    void deleteUserById(Long userId);
+
+    void checkEmail(String email);
+}
diff --git a/src/main/java/ru/practicum/shareit/user/repository/UserRepositoryImpl.java b/src/main/java/ru/practicum/shareit/user/repository/UserRepositoryImpl.java
new file mode 100644
index 0000000..d52efba
--- /dev/null
+++ b/src/main/java/ru/practicum/shareit/user/repository/UserRepositoryImpl.java
@@ -0,0 +1,56 @@
+package ru.practicum.shareit.user.repository;
+
+import org.springframework.stereotype.Repository;
+import ru.practicum.shareit.exception.AlreadyExistException;
+import ru.practicum.shareit.user.model.User;
+
+import java.util.*;
+
+@Repository
+public class UserRepositoryImpl implements UserRepository {
+
+    private final Map<Long, User> users = new HashMap<>();
+
+    @Override
+    public List<User> getUsers() {
+        return new ArrayList<>(users.values());
+    }
+
+    @Override
+    public Optional<User> getUserById(Long userId) {
+        return Optional.ofNullable(users.get(userId));
+    }
+
+    @Override
+    public User createUser(User user) {
+        user.setId(getNewUserId());
+        users.put(user.getId(), user);
+        return users.get(user.getId());
+    }
+
+    @Override
+    public User updateUser(User user) {
+        users.put(user.getId(), user);
+        return users.get(user.getId());
+    }
+
+    @Override
+    public void deleteUserById(Long userId) {
+        users.remove(userId);
+    }
+
+    @Override
+    public void checkEmail(String email) {
+        if (getUsers().stream()
+                .map(User::getEmail)
+                .anyMatch(email::equals)) {
+            throw new AlreadyExistException("Пользователь с почтой " + email + " уже существует");
+        }
+    }
+
+    private Long getNewUserId() {
+        return users.keySet().stream()
+                .max(Long::compareTo)
+                .orElse(0L) + 1;
+    }
+}
diff --git a/src/main/java/ru/practicum/shareit/user/service/UserService.java b/src/main/java/ru/practicum/shareit/user/service/UserService.java
new file mode 100644
index 0000000..045ba1a
--- /dev/null
+++ b/src/main/java/ru/practicum/shareit/user/service/UserService.java
@@ -0,0 +1,17 @@
+package ru.practicum.shareit.user.service;
+
+import ru.practicum.shareit.user.dto.UserDto;
+import ru.practicum.shareit.user.model.User;
+
+public interface UserService {
+
+    UserDto getUserById(Long userId);
+
+    User getUserWithCheck(Long userId);
+
+    UserDto createUser(UserDto user);
+
+    UserDto updateUser(UserDto user, Long userId);
+
+    void deleteUserById(Long userId);
+}
diff --git a/src/main/java/ru/practicum/shareit/user/service/UserServiceImpl.java b/src/main/java/ru/practicum/shareit/user/service/UserServiceImpl.java
new file mode 100644
index 0000000..8cc1711
--- /dev/null
+++ b/src/main/java/ru/practicum/shareit/user/service/UserServiceImpl.java
@@ -0,0 +1,61 @@
+package ru.practicum.shareit.user.service;
+
+import lombok.AllArgsConstructor;
+import lombok.extern.slf4j.Slf4j;
+import org.springframework.stereotype.Service;
+import ru.practicum.shareit.exception.NotFoundException;
+import ru.practicum.shareit.user.dto.UserDto;
+import ru.practicum.shareit.user.mapper.UserMapper;
+import ru.practicum.shareit.user.model.User;
+import ru.practicum.shareit.user.repository.UserRepository;
+
+@Slf4j
+@Service
+@AllArgsConstructor
+public class UserServiceImpl implements UserService {
+
+    private final UserRepository userRepository;
+
+    @Override
+    public UserDto getUserById(Long userId) {
+        log.info("Запрос пользователя с ID = {}", userId);
+        User userById = getUserWithCheck(userId);
+        return UserMapper.toUserDto(userById);
+    }
+
+    @Override
+    public User getUserWithCheck(Long userId) {
+        return userRepository.getUserById(userId)
+                .orElseThrow(() -> new NotFoundException("Пользователь с ID = " + userId + " не найден"));
+    }
+
+    @Override
+    public UserDto createUser(UserDto userDto) {
+        log.info("Создание пользователя");
+        userRepository.checkEmail(userDto.getEmail());
+        return UserMapper.toUserDto(
+                userRepository.createUser(
+                        UserMapper.toUser(userDto)));
+    }
+
+    @Override
+    public UserDto updateUser(UserDto userDto, Long userId) {
+        log.info("Обновление пользователя с ID = {}", userId);
+        User findUser = getUserWithCheck(userId);
+        if (userDto.getEmail() != null && !userDto.getEmail().equals(findUser.getEmail())) {
+            userRepository.checkEmail(userDto.getEmail());
+        }
+        findUser.setEmail(userDto.getEmail() == null || userDto.getEmail().isBlank() ?
+                findUser.getEmail() : userDto.getEmail());
+        findUser.setName(userDto.getName() == null || userDto.getName().isBlank() ?
+                findUser.getName() : userDto.getName());
+        return UserMapper.toUserDto(userRepository.updateUser(findUser));
+    }
+
+    @Override
+    public void deleteUserById(Long userId) {
+        log.info("Удаление пользователя с ID = {}", userId);
+        getUserWithCheck(userId);
+        userRepository.deleteUserById(userId);
+    }
+}