diff --git a/pom.xml b/pom.xml
index 5e0cab1..48637fc 100644
--- a/pom.xml
+++ b/pom.xml
@@ -65,6 +65,24 @@
             <artifactId>picocli</artifactId>
             <version>4.7.6</version>
         </dependency>
+
+        <dependency>
+            <groupId>com.fasterxml.jackson.core</groupId>
+            <artifactId>jackson-core</artifactId>
+            <version>2.18.1</version>
+        </dependency>
+
+        <dependency>
+            <groupId>com.fasterxml.jackson.core</groupId>
+            <artifactId>jackson-databind</artifactId>
+            <version>2.18.1</version>
+        </dependency>
+
+        <dependency>
+            <groupId>com.fasterxml.jackson.core</groupId>
+            <artifactId>jackson-annotations</artifactId>
+            <version>2.18.1</version>
+        </dependency>
     </dependencies>
 
     <build>
diff --git a/src/main/java/ua/com/javarush/gnew/m2/repository/ContactDtoRepository.java b/src/main/java/ua/com/javarush/gnew/m2/repository/ContactDtoRepository.java
index 0381963..b81e94d 100644
--- a/src/main/java/ua/com/javarush/gnew/m2/repository/ContactDtoRepository.java
+++ b/src/main/java/ua/com/javarush/gnew/m2/repository/ContactDtoRepository.java
@@ -1,17 +1,66 @@
 package ua.com.javarush.gnew.m2.repository;
 
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.SerializationFeature;
+import java.io.File;
+import java.io.IOException;
+import java.util.ArrayList;
 import java.util.List;
 import java.util.Optional;
+import java.util.stream.Collectors;
+import lombok.SneakyThrows;
 import ua.com.javarush.gnew.m2.dto.ContactDto;
 
 public interface ContactDtoRepository {
-  List<ContactDto> findAll();
+  ObjectMapper objectMapper = new ObjectMapper().enable(SerializationFeature.INDENT_OUTPUT);
 
-  Optional<ContactDto> findById(long id);
+  @SneakyThrows
+  default List<ContactDto> findAll() throws IOException {
+    File file = new File("demo.st");
+    if (!file.exists()) {
+      return new ArrayList<>();
+    }
 
-  void deleteById(long id);
+    return objectMapper.readValue(
+        file, objectMapper.getTypeFactory().constructCollectionType(List.class, ContactDto.class));
+  }
 
-  void saveAll(List<ContactDto> contacts);
+  @SneakyThrows
+  default Optional<ContactDto> findById(long id) throws IOException {
+    return findAll().stream().filter(contact -> contact.getId() == id).findFirst();
+  }
 
-  void save(ContactDto contactDto);
+  default void deleteById(long id) throws IOException {
+    Optional<ContactDto> contactToDelete = findById(id);
+    if (contactToDelete.isPresent()) {
+      List<ContactDto> contacts = findAll();
+      contacts.remove(contactToDelete.get());
+      saveAll(contacts);
+    } else {
+      System.out.println("Контакт с id " + id + " не найден.");
+    }
+  }
+
+  @SneakyThrows
+  default void saveAll(List<ContactDto> contacts) throws IOException {
+    objectMapper.writeValue(new File("demo.st"), contacts);
+  }
+  ;
+
+  default void save(ContactDto contactDto) throws IOException {
+    List<ContactDto> contacts = findAll();
+    contacts.add(contactDto);
+    saveAll(contacts);
+  }
+
+  default List<ContactDto> findByKeyword(String keyword) throws IOException {
+    List<ContactDto> contacts = findAll();
+    return contacts.stream()
+        .filter(
+            contact ->
+                contact.getFullName().contains(keyword)
+                    || contact.getPhones().stream().anyMatch(phones -> phones.contains(keyword))
+                    || contact.getEmails().stream().anyMatch(emails -> emails.contains(keyword)))
+        .collect(Collectors.toList());
+  }
 }
diff --git a/src/main/java/ua/com/javarush/gnew/m2/service/SimplePhoneBook.java b/src/main/java/ua/com/javarush/gnew/m2/service/SimplePhoneBook.java
index eeda8d8..abfdcd4 100644
--- a/src/main/java/ua/com/javarush/gnew/m2/service/SimplePhoneBook.java
+++ b/src/main/java/ua/com/javarush/gnew/m2/service/SimplePhoneBook.java
@@ -3,17 +3,34 @@
 import java.util.Collections;
 import java.util.List;
 import java.util.Optional;
+import java.util.stream.Collectors;
+import lombok.SneakyThrows;
 import ua.com.javarush.gnew.m2.dto.ContactDto;
+import ua.com.javarush.gnew.m2.repository.ContactDtoRepository;
 
-public class SimplePhoneBook implements PhoneBookInterface {
+public class SimplePhoneBook implements PhoneBookInterface, ContactDtoRepository {
   @Override
   public ContactDto add(ContactDto contactDto) {
-    return contactDto;
+
+    return ContactDto.builder()
+        .fullName(contactDto.getFullName())
+        .phones(List.of(String.valueOf(contactDto.getPhones())))
+        .emails(List.of(String.valueOf(contactDto.getEmails())))
+        .build();
   }
 
+  @SneakyThrows
   @Override
   public List<ContactDto> search(String str) {
-    return Collections.emptyList();
+
+    List<ContactDto> contacts = findAll();
+    return contacts.stream()
+        .filter(
+            contact ->
+                contact.getFullName().contains(str)
+                    || contact.getPhones().stream().anyMatch(phones -> phones.contains(str))
+                    || contact.getEmails().stream().anyMatch(emails -> emails.contains(str)))
+        .collect(Collectors.toList());
   }
 
   @Override