diff --git a/src/superannotate_schemas/schemas/base.py b/src/superannotate_schemas/schemas/base.py
index baed528..85d0c57 100644
--- a/src/superannotate_schemas/schemas/base.py
+++ b/src/superannotate_schemas/schemas/base.py
@@ -65,8 +65,8 @@ class AxisPoint(BaseModel):
 class BaseAttribute(BaseModel):
     id: Optional[StrictInt]
     group_id: Optional[StrictInt] = Field(alias="groupId")
-    name: NotEmptyStr
-    group_name: NotEmptyStr = Field(alias="groupName")
+    name: Optional[NotEmptyStr]
+    group_name: Optional[NotEmptyStr] = Field(alias="groupName")
 
 
 class Tag(BaseModel):
@@ -222,7 +222,7 @@ class BaseVectorInstance(BaseImageAnnotationInstance):
     group_id: Optional[int] = Field(alias="groupId")
 
 
-class PixelColor(BaseModel):
+class HexColor(BaseModel):
     __root__: ColorType
 
     @validator("__root__")
diff --git a/src/superannotate_schemas/schemas/classes.py b/src/superannotate_schemas/schemas/classes.py
new file mode 100644
index 0000000..638f876
--- /dev/null
+++ b/src/superannotate_schemas/schemas/classes.py
@@ -0,0 +1,49 @@
+from typing import Optional
+from typing import List
+
+from superannotate_schemas.schemas.base import BaseModel
+from superannotate_schemas.schemas.base import TrackableModel
+from superannotate_schemas.schemas.base import TimedBaseModel
+from superannotate_schemas.schemas.base import StrictInt
+from superannotate_schemas.schemas.base import StrictStr
+from superannotate_schemas.schemas.base import HexColor
+from superannotate_schemas.schemas.enums import ClassTypeEnum
+
+
+class Attribute(TimedBaseModel):
+    id: Optional[StrictInt]
+    group_id: Optional[StrictInt]
+    project_id: Optional[StrictInt]
+    name: StrictStr
+    count: Optional[StrictInt]
+
+    def __hash__(self):
+        return hash(f"{self.id}{self.group_id}{self.name}")
+
+
+class AttributeGroup(TimedBaseModel):
+    id: Optional[StrictInt]
+    class_id: Optional[StrictInt]
+    name: StrictStr
+    is_multiselect: Optional[bool]
+    attributes: List[Attribute]
+
+    def __hash__(self):
+        return hash(f"{self.id}{self.class_id}{self.name}")
+
+
+class AnnotationClass(TimedBaseModel):
+    id: Optional[StrictInt]
+    project_id: Optional[StrictInt]
+    type: ClassTypeEnum = ClassTypeEnum.OBJECT
+    name: StrictStr
+    color: HexColor
+    count: Optional[StrictInt]
+    attribute_groups: List[AttributeGroup]
+
+    def __hash__(self):
+        return hash(f"{self.id}{self.type}{self.name}")
+
+
+class AnnotationClasses(BaseModel):
+    __root__: List[AnnotationClass]
diff --git a/src/superannotate_schemas/schemas/enums.py b/src/superannotate_schemas/schemas/enums.py
index e8ccdbb..1d8cb8e 100644
--- a/src/superannotate_schemas/schemas/enums.py
+++ b/src/superannotate_schemas/schemas/enums.py
@@ -41,6 +41,6 @@ class BaseImageRoleEnum(str, Enum):
     QA = "QA"
 
 
-class TagTypeEnum(str, Enum):
-    TAG = "tag"
+class ClassTypeEnum(str, Enum):
     OBJECT = "object"
+    TAG = "tag"
diff --git a/src/superannotate_schemas/schemas/external/pixel.py b/src/superannotate_schemas/schemas/external/pixel.py
index b21b3d5..23de3a1 100644
--- a/src/superannotate_schemas/schemas/external/pixel.py
+++ b/src/superannotate_schemas/schemas/external/pixel.py
@@ -6,7 +6,7 @@
 from superannotate_schemas.schemas.base import BaseImageMetadata
 from superannotate_schemas.schemas.base import NotEmptyStr
 from superannotate_schemas.schemas.base import StrictStr
-from superannotate_schemas.schemas.base import PixelColor
+from superannotate_schemas.schemas.base import HexColor
 from superannotate_schemas.schemas.base import Tag
 from superannotate_schemas.schemas.base import Comment
 
@@ -25,7 +25,7 @@ class MetaData(BaseImageMetadata):
 
 
 class AnnotationPart(BaseModel):
-    color: PixelColor
+    color: HexColor
 
 
 class AnnotationInstance(BaseImageAnnotationInstance):
diff --git a/src/superannotate_schemas/schemas/internal/pixel.py b/src/superannotate_schemas/schemas/internal/pixel.py
index 3d73ec1..0b4d981 100644
--- a/src/superannotate_schemas/schemas/internal/pixel.py
+++ b/src/superannotate_schemas/schemas/internal/pixel.py
@@ -2,7 +2,7 @@
 from typing import Optional
 
 from superannotate_schemas.schemas.base import BaseImageMetadata as Metadata
-from superannotate_schemas.schemas.base import PixelColor
+from superannotate_schemas.schemas.base import HexColor
 from superannotate_schemas.schemas.base import BaseAttribute
 from superannotate_schemas.schemas.base import BaseImageAnnotationInstance
 from superannotate_schemas.schemas.base import Tag
@@ -19,7 +19,7 @@ class Attribute(BaseAttribute):
 
 
 class AnnotationPart(BaseModel):
-    color: PixelColor
+    color: HexColor
 
 
 class AnnotationInstance(BaseImageAnnotationInstance):
diff --git a/src/superannotate_schemas/validators.py b/src/superannotate_schemas/validators.py
index a093e03..3072b3d 100644
--- a/src/superannotate_schemas/validators.py
+++ b/src/superannotate_schemas/validators.py
@@ -95,6 +95,7 @@ class AnnotationValidators:
             ValidatorFactory.get_validator(ExternalDocumentAnnotation),
             ValidatorFactory.get_validator(InternalDocumentAnnotation)
         )
+
     }
 
     @classmethod