diff --git a/knowledgehub/vectorstores/__init__.py b/knowledgehub/vectorstores/__init__.py
index e6c8f0c..62e3127 100644
--- a/knowledgehub/vectorstores/__init__.py
+++ b/knowledgehub/vectorstores/__init__.py
@@ -1,4 +1,5 @@
 from .base import BaseVectorStore
 from .chroma import ChromaVectorStore
+from .in_memory import InMemoryVectorStore
 
-__all__ = ["BaseVectorStore", "ChromaVectorStore"]
+__all__ = ["BaseVectorStore", "ChromaVectorStore", "InMemoryVectorStore"]
diff --git a/knowledgehub/vectorstores/base.py b/knowledgehub/vectorstores/base.py
index 3778a15..ac66e6b 100644
--- a/knowledgehub/vectorstores/base.py
+++ b/knowledgehub/vectorstores/base.py
@@ -1,6 +1,7 @@
 from abc import ABC, abstractmethod
 from typing import Any, List, Optional, Tuple, Type, Union
 
+from llama_index.schema import NodeRelationship, RelatedNodeInfo
 from llama_index.vector_stores.types import BasePydanticVectorStore
 from llama_index.vector_stores.types import VectorStore as LIVectorStore
 from llama_index.vector_stores.types import VectorStoreQuery
@@ -118,6 +119,9 @@ class LlamaIndexVectorStore(BaseVectorStore):
         if ids is not None:
             for node, id in zip(nodes, ids):
                 node.id_ = id
+                node.relationships = {
+                    NodeRelationship.SOURCE: RelatedNodeInfo(node_id=id)
+                }
 
         return self._client.add(nodes=nodes)  # type: ignore
 
diff --git a/knowledgehub/vectorstores/in_memory.py b/knowledgehub/vectorstores/in_memory.py
new file mode 100644
index 0000000..86e82d2
--- /dev/null
+++ b/knowledgehub/vectorstores/in_memory.py
@@ -0,0 +1,57 @@
+"""Simple vector store index."""
+
+from typing import Any, Optional, Type
+
+import fsspec
+from llama_index.vector_stores import SimpleVectorStore as LISimpleVectorStore
+from llama_index.vector_stores.simple import SimpleVectorStoreData
+
+from kotaemon.vectorstores.base import LlamaIndexVectorStore
+
+
+class InMemoryVectorStore(LlamaIndexVectorStore):
+    _li_class: Type[LISimpleVectorStore] = LISimpleVectorStore
+    store_text: bool = False
+
+    def __init__(
+        self,
+        data: Optional[SimpleVectorStoreData] = None,
+        fs: Optional[fsspec.AbstractFileSystem] = None,
+        **kwargs: Any,
+    ) -> None:
+        """Initialize params."""
+        self._data = data or SimpleVectorStoreData()
+        self._fs = fs or fsspec.filesystem("file")
+
+        super().__init__(
+            data=data,
+            fs=fs,
+            **kwargs,
+        )
+
+    def save(
+        self,
+        save_path: str,
+        fs: Optional[fsspec.AbstractFileSystem] = None,
+        **kwargs,
+    ):
+
+        """save a simpleVectorStore to a dictionary.
+
+        Args:
+            save_path: Path of saving vector to disk.
+            fs: An abstract super-class for pythonic file-systems
+        """
+        self._client.persist(persist_path=save_path, fs=fs)
+
+    def load(
+        self, load_path: str, fs: Optional[fsspec.AbstractFileSystem] = None
+    ) -> "InMemoryVectorStore":
+
+        """Create a SimpleKVStore from a load directory.
+
+        Args:
+            load_path: Path of loading vector.
+            fs: An abstract super-class for pythonic file-systems
+        """
+        return self._client.from_persist_path(persist_path=load_path, fs=fs)
diff --git a/tests/test_vectorstore.py b/tests/test_vectorstore.py
index 96e9ba1..8b3556c 100644
--- a/tests/test_vectorstore.py
+++ b/tests/test_vectorstore.py
@@ -1,5 +1,7 @@
+import json
+
 from kotaemon.documents.base import Document
-from kotaemon.vectorstores import ChromaVectorStore
+from kotaemon.vectorstores import ChromaVectorStore, InMemoryVectorStore
 
 
 class TestChromaVectorStore:
@@ -59,3 +61,41 @@ class TestChromaVectorStore:
 
         _, _, out_ids = db.query(embedding=[0.42, 0.52, 0.53], top_k=1)
         assert out_ids == ["b"]
+
+
+class TestSimpleVectorStore:
+    def test_add(self):
+        """Test that add func adds correctly."""
+
+        embeddings = [[0.1, 0.2, 0.3], [0.4, 0.5, 0.6]]
+        metadatas = [{"a": 1, "b": 2}, {"a": 3, "b": 4}]
+        ids = ["1", "2"]
+        db = InMemoryVectorStore()
+
+        output = db.add(embeddings=embeddings, metadatas=metadatas, ids=ids)
+        assert output == ids, "Excepted output to be the same as ids"
+
+    def test_save_load_delete(self, tmp_path):
+        """Test that delete func deletes correctly."""
+        embeddings = [[0.1, 0.2, 0.3], [0.4, 0.5, 0.6], [0.7, 0.8, 0.9]]
+        metadatas = [{"a": 1, "b": 2}, {"a": 3, "b": 4}, {"a": 5, "b": 6}]
+        ids = ["1", "2", "3"]
+        db = InMemoryVectorStore()
+        db.add(embeddings=embeddings, metadatas=metadatas, ids=ids)
+        db.delete(["3"])
+        db.save(save_path=tmp_path / "test_save_load_delete.json")
+        f = open(tmp_path / "test_save_load_delete.json")
+        data = json.load(f)
+        assert (
+            "1" and "2" in data["text_id_to_ref_doc_id"]
+        ), "persist function does not save data completely"
+        assert (
+            "3" not in data["text_id_to_ref_doc_id"]
+        ), "delete function does not delete data completely"
+        db2 = InMemoryVectorStore()
+        output = db2.load(load_path=tmp_path / "test_save_load_delete.json")
+        assert output.get("2") == [
+            0.4,
+            0.5,
+            0.6,
+        ], "persist function does not load data completely"