diff --git a/client-api/src/main/java/ru/dragonestia/picker/api/repository/NodeRepository.java b/client-api/src/main/java/ru/dragonestia/picker/api/repository/NodeRepository.java
index 20e1424..18927bc 100644
--- a/client-api/src/main/java/ru/dragonestia/picker/api/repository/NodeRepository.java
+++ b/client-api/src/main/java/ru/dragonestia/picker/api/repository/NodeRepository.java
@@ -2,7 +2,7 @@ package ru.dragonestia.picker.api.repository;
 
 import ru.dragonestia.picker.api.exception.InvalidNodeIdentifierException;
 import ru.dragonestia.picker.api.exception.NodeAlreadyExistException;
-import ru.dragonestia.picker.api.repository.details.NodeDetails;
+import ru.dragonestia.picker.api.model.node.NodeDetails;
 import ru.dragonestia.picker.api.repository.response.type.RNode;
 
 import java.util.List;
diff --git a/client-api/src/main/java/ru/dragonestia/picker/api/repository/RoomRepository.java b/client-api/src/main/java/ru/dragonestia/picker/api/repository/RoomRepository.java
index 73a1c80..8d899d1 100644
--- a/client-api/src/main/java/ru/dragonestia/picker/api/repository/RoomRepository.java
+++ b/client-api/src/main/java/ru/dragonestia/picker/api/repository/RoomRepository.java
@@ -1,7 +1,7 @@
 package ru.dragonestia.picker.api.repository;
 
 import ru.dragonestia.picker.api.exception.*;
-import ru.dragonestia.picker.api.repository.details.RoomDetails;
+import ru.dragonestia.picker.api.model.room.RoomDetails;
 import ru.dragonestia.picker.api.repository.response.type.RNode;
 import ru.dragonestia.picker.api.repository.response.type.RRoom;
 
diff --git a/client-api/src/main/java/ru/dragonestia/picker/api/repository/UserRepository.java b/client-api/src/main/java/ru/dragonestia/picker/api/repository/UserRepository.java
index b5bfeee..a69047a 100644
--- a/client-api/src/main/java/ru/dragonestia/picker/api/repository/UserRepository.java
+++ b/client-api/src/main/java/ru/dragonestia/picker/api/repository/UserRepository.java
@@ -3,14 +3,13 @@ package ru.dragonestia.picker.api.repository;
 import ru.dragonestia.picker.api.exception.NodeNotFoundException;
 import ru.dragonestia.picker.api.exception.RoomAreFullException;
 import ru.dragonestia.picker.api.exception.RoomNotFoundException;
-import ru.dragonestia.picker.api.repository.details.RoomDetails;
+import ru.dragonestia.picker.api.model.room.RoomDetails;
+import ru.dragonestia.picker.api.model.user.UserDetails;
 import ru.dragonestia.picker.api.repository.response.type.RRoom;
 import ru.dragonestia.picker.api.repository.response.type.RUser;
-import ru.dragonestia.picker.api.repository.details.UserDetails;
 
 import java.util.Collection;
 import java.util.List;
-import java.util.Optional;
 import java.util.Set;
 
 public interface UserRepository {
diff --git a/client-api/src/main/java/ru/dragonestia/picker/api/repository/details/NodeDetails.java b/client-api/src/main/java/ru/dragonestia/picker/api/repository/details/NodeDetails.java
deleted file mode 100644
index b374ec5..0000000
--- a/client-api/src/main/java/ru/dragonestia/picker/api/repository/details/NodeDetails.java
+++ /dev/null
@@ -1,5 +0,0 @@
-package ru.dragonestia.picker.api.repository.details;
-
-public enum NodeDetails {
-    PERSIST
-}
diff --git a/client-api/src/main/java/ru/dragonestia/picker/api/repository/details/UserDetails.java b/client-api/src/main/java/ru/dragonestia/picker/api/repository/details/UserDetails.java
deleted file mode 100644
index 9a4ad43..0000000
--- a/client-api/src/main/java/ru/dragonestia/picker/api/repository/details/UserDetails.java
+++ /dev/null
@@ -1,5 +0,0 @@
-package ru.dragonestia.picker.api.repository.details;
-
-public enum UserDetails {
-    COUNT_ROOMS
-}
diff --git a/client-api/src/main/java/ru/dragonestia/picker/api/repository/response/type/RNode.java b/client-api/src/main/java/ru/dragonestia/picker/api/repository/response/type/RNode.java
index 303a6ec..2a82d92 100644
--- a/client-api/src/main/java/ru/dragonestia/picker/api/repository/response/type/RNode.java
+++ b/client-api/src/main/java/ru/dragonestia/picker/api/repository/response/type/RNode.java
@@ -1,8 +1,8 @@
 package ru.dragonestia.picker.api.repository.response.type;
 
 import io.swagger.v3.oas.annotations.media.Schema;
+import ru.dragonestia.picker.api.model.node.NodeDetails;
 import ru.dragonestia.picker.api.repository.response.type.type.PickingMode;
-import ru.dragonestia.picker.api.repository.details.NodeDetails;
 
 import java.util.HashMap;
 import java.util.Map;
diff --git a/client-api/src/main/java/ru/dragonestia/picker/api/repository/response/type/RRoom.java b/client-api/src/main/java/ru/dragonestia/picker/api/repository/response/type/RRoom.java
index 4d83f49..0b1bfdd 100644
--- a/client-api/src/main/java/ru/dragonestia/picker/api/repository/response/type/RRoom.java
+++ b/client-api/src/main/java/ru/dragonestia/picker/api/repository/response/type/RRoom.java
@@ -1,7 +1,7 @@
 package ru.dragonestia.picker.api.repository.response.type;
 
 import io.swagger.v3.oas.annotations.media.Schema;
-import ru.dragonestia.picker.api.repository.details.RoomDetails;
+import ru.dragonestia.picker.api.model.room.RoomDetails;
 
 import java.beans.Transient;
 import java.util.HashMap;
diff --git a/client-api/src/main/java/ru/dragonestia/picker/api/repository/response/type/RUser.java b/client-api/src/main/java/ru/dragonestia/picker/api/repository/response/type/RUser.java
index c48d7db..85990af 100644
--- a/client-api/src/main/java/ru/dragonestia/picker/api/repository/response/type/RUser.java
+++ b/client-api/src/main/java/ru/dragonestia/picker/api/repository/response/type/RUser.java
@@ -1,7 +1,7 @@
 package ru.dragonestia.picker.api.repository.response.type;
 
 import io.swagger.v3.oas.annotations.media.Schema;
-import ru.dragonestia.picker.api.repository.details.UserDetails;
+import ru.dragonestia.picker.api.model.user.UserDetails;
 
 import java.util.HashMap;
 import java.util.Map;
diff --git a/client-api/src/main/java/ru/dragonestia/picker/api/repository/type/NodeIdentifier.java b/client-api/src/main/java/ru/dragonestia/picker/api/repository/type/NodeIdentifier.java
new file mode 100644
index 0000000..abe2ef5
--- /dev/null
+++ b/client-api/src/main/java/ru/dragonestia/picker/api/repository/type/NodeIdentifier.java
@@ -0,0 +1,24 @@
+package ru.dragonestia.picker.api.repository.type;
+
+import org.jetbrains.annotations.NotNull;
+import ru.dragonestia.picker.api.util.IdentifierValidator;
+
+import java.security.InvalidParameterException;
+
+public final class NodeIdentifier extends ValueObject<String> {
+
+    private NodeIdentifier(String value) {
+        super(value);
+    }
+
+    @Override
+    protected void validate(String value) {
+        if (IdentifierValidator.forNode(value)) return;
+
+        throw new InvalidParameterException("Invalid node identifier");
+    }
+
+    public static NodeIdentifier of(@NotNull String value) {
+        return new NodeIdentifier(value);
+    }
+}
diff --git a/client-api/src/main/java/ru/dragonestia/picker/api/repository/type/RoomIdentifier.java b/client-api/src/main/java/ru/dragonestia/picker/api/repository/type/RoomIdentifier.java
new file mode 100644
index 0000000..1a0592d
--- /dev/null
+++ b/client-api/src/main/java/ru/dragonestia/picker/api/repository/type/RoomIdentifier.java
@@ -0,0 +1,24 @@
+package ru.dragonestia.picker.api.repository.type;
+
+import org.jetbrains.annotations.NotNull;
+import ru.dragonestia.picker.api.util.IdentifierValidator;
+
+import java.security.InvalidParameterException;
+
+public class RoomIdentifier extends ValueObject<String> {
+
+    private RoomIdentifier(String value) {
+        super(value);
+    }
+
+    @Override
+    protected void validate(String value) {
+        if(IdentifierValidator.forRoom(value)) return;
+
+        throw new InvalidParameterException("Invalid room identifier");
+    }
+
+    public static RoomIdentifier of(@NotNull String value) {
+        return new RoomIdentifier(value);
+    }
+}
diff --git a/client-api/src/main/java/ru/dragonestia/picker/api/repository/type/ValueObject.java b/client-api/src/main/java/ru/dragonestia/picker/api/repository/type/ValueObject.java
new file mode 100644
index 0000000..0207855
--- /dev/null
+++ b/client-api/src/main/java/ru/dragonestia/picker/api/repository/type/ValueObject.java
@@ -0,0 +1,18 @@
+package ru.dragonestia.picker.api.repository.type;
+
+abstract class ValueObject<T> {
+
+    private final T value;
+
+    ValueObject(T value) {
+        validate(value);
+
+        this.value = value;
+    }
+
+    protected abstract void validate(T value);
+
+    public T getValue() {
+        return value;
+    }
+}