diff --git a/registry/data-models/__init__.py b/registry/data-models/__init__.py
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index 000000000..e69de29bb
diff --git a/registry/data-models/data-model-diagram.md b/registry/data-models/data-model-diagram.md
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+
+# Feathr Abstract backend Data Model Diagram
+
+This file defines abstract backend data models diagram for feature registry.
+[Python Code](./models.py)
+
+```mermaid
+classDiagram
+    Project "1" --> "n" FeatureName : contains
+    Project "1" --> "n" Anchor : contains
+    FeatureName "1" --> "n" Feature : contains
+    Anchor "1" --> "n" Feature : contains
+    Feature <|-- AnchorFeature : extends
+    Feature <|-- DerivedFeature: extends
+    Feature --> Transformation
+    Feature  -->  Transformation : contains
+    Source <|-- DataSource: extends
+    Source <|-- MultiFeatureSource: extends
+    MultiFeatureSource "1" --> "1..n" FeatureSource: contains
+    AnchorFeature  -->  DataSource : contains
+    DerivedFeature -->  MultiFeatureSource: contains
+
+    class Source{
+    }
+    class DataSource{
+    }
+    class FeatureSource{
+        +FeatureNameId feature_name_id
+    }
+    class MultiFeatureSource{
+        +List[FeatureSource] sources
+    }
+    class Feature{
+        +FeatureId id
+        +FeatureNameId feature_namme_id
+        +Source source
+        +Transformation transformation
+    }
+    class AnchorFeature{
+        +DataSource source
+    }
+    class DerivedFeature{
+        +MultiFeatureSource source
+    }
+    class FeatureName{
+        +FeatureNameId id
+        +ProjectId project_id
+        +List[FeatureId] feature_ids
+    }
+    class Project{
+        +ProjectId id
+        +List[FeatureNameId] feature_name_ids
+        +List[AnchorId] anchor_ids
+    }
+    class Anchor{
+        +AnchorId id
+        +ProjectId project_id
+        +DataSource source
+        +List[FeatureId] anchor_feature_ids
+    }
+```
\ No newline at end of file
diff --git a/registry/data-models/models.py b/registry/data-models/models.py
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+from pydantic import BaseModel
+from typing import List
+
+"""
+This file defines abstract backend data models for feature registry.
+Backend data models will be used by backend API server to talk to feature registry backend.
+Purpose of this is to decouple backend data models from API specific data models.
+For each feature registry provider/implementation, they will extend this abstract
+data models and backend API.
+Diagram of the data models:  ./data-model-diagram.md
+"""
+
+
+class FeatureId(BaseModel):
+    """
+    Id for Feature, it's unique ID represents Feature.
+    Id can be a simple string, int or complex key.
+    """
+    id: str  # id of a feature
+
+
+class FeatureNameId(BaseModel):
+    """
+    Id for FeatureName, it's unique ID represents FeatureName.
+    Id can be a simple string, int or complex key.
+    """
+    id: str  # id of a FeatureName
+
+
+class AnchorId(BaseModel):
+    """
+    Id for Anchor, it's unique ID represents Anchor.
+    Id can be a simple string, int or complex key.
+    """
+    id: str  # id of a anchor
+
+
+class ProjectId(BaseModel):
+    """
+    Id for Project, it's unique ID represents Project.
+    Id can be a simple string, int or complex key.
+    """
+    id: str  # id of a project
+
+
+class Source(BaseModel):
+    """
+    Source of the feature.
+    It defines where the feature is extracted or derived from.
+    """
+    pass
+
+
+class DataSource(Source):
+    """
+    Data source of the feature.
+    It defines the raw data source the feature is extracted from.
+    """
+    pass
+
+
+class FeatureSource(BaseModel):
+    """
+    Represents a feature source for a derived feature. That is, it is a source 'FeatureName' which is used for
+    creating other derived features.
+    """
+    input_feature_name_id: FeatureNameId  # Input feature name Key
+
+
+class MultiFeatureSource(Source):
+    """
+    Feature sources of the feature.
+    It defines one to many features where the feature is derived from.
+    """
+    sources: List[FeatureSource]  # All source features which the feature is derived from
+    pass
+
+
+class Transformation(BaseModel):
+    """
+    The transformation of a Feature.
+    A transformation function represents the transformation logic to produce feature value from the source of FeatureAnchor
+    """
+    pass
+
+
+class Feature(BaseModel):
+    """
+    Actual implementation of FeatureName.
+    An implementation defines where a feature is extracted from (Source) and how it is computed (Transformation).
+    The Source of a feature can be raw data sources and/or other features.
+    """
+    id: FeatureId  # Unique ID for Feature
+    feature_name_id: FeatureNameId  # Id of the feature name that the feature belongs to
+    source: Source  # Source can be either data source or feature source
+    transformation: Transformation  # transformation logic to produce feature value
+
+
+class AnchorFeature(Feature):
+    """
+    Feature implementation of FeatureName which anchored to a data source.
+    """
+    source: DataSource  # Raw data source where the feature is extracted from
+
+
+class DerivedFeature(Feature):
+    """
+    Feature implementation that is derived from other FeatureNames.
+    """
+    source: MultiFeatureSource  # Source features where the feature is derived from
+
+
+class FeatureName(BaseModel):
+    """
+    Named Feature Interface that can be backed by multiple Feature implementations across
+    different environments accessing different sources (data lake access for batch training,
+    KV store access for online serving). Each FeatureName is defined by feature producer.
+    Feature consumers reference a feature by that name to access that feature data,
+    agnostic of runtime environment. Each FeatureName also encloses attributes that does not
+    change across implementations.
+    """
+    id: FeatureNameId  # unique ID for FeatureName, used to extract data for current FeatureName
+    project_id: ProjectId  # ID of the project the FeatureName belongs to
+    feature_ids: List[FeatureId]  # List of ids of feature that the FeatureName has
+
+
+class Project(BaseModel):
+    """
+    Group of FeatureNames. It can be a project the team is working on,
+    or a namespace which related FeatureNames have.
+    """
+    id: ProjectId  # Unique ID of the project.
+    feature_name_ids: List[FeatureNameId]  # List of feature name ids that the project has
+    anchor_ids: List[AnchorId]   # List of Anchor ids that the project has
+
+
+class Anchor(BaseModel):
+    """
+    Group of AnchorFeatures which anchored on same DataSource.
+    This is mainly used by feature producer gather information about DataSource
+    and FeatureImplementations associated with the DataSource.
+    """
+    id: AnchorId  # Unique ID for Anchor
+    project_id: ProjectId  # ID of Project that the anchor belongs to
+    source: DataSource  # data source of the Anchor
+    anchor_feature_ids: List[FeatureId]  # List of anchor features that the anchor has