diff --git a/plesna/graph.py b/plesna/graph.py
new file mode 100644
index 0000000..00b8aff
--- /dev/null
+++ b/plesna/graph.py
@@ -0,0 +1,33 @@
+from typing import Callable
+
+from pydantic import BaseModel
+
+
+class Node(BaseModel):
+    name: str
+    infos: dict = {}
+
+    def __hash__(self):
+        return hash(self.name)
+
+
+class Edge(BaseModel):
+    arrow_name: str
+    source: Node
+    target: Node
+    edge_kwrds: dict = {}
+
+
+class Graph:
+    def __init__(self):
+        self._edges = []
+        self._nodes = set()
+
+    def append(self, edge: Edge):
+        self._edges.append(edge)
+        self._nodes.add(edge.source)
+        self._nodes.add(edge.target)
+
+    @property
+    def nodes(self):
+        return self._nodes
diff --git a/tests/graphs/test_graph.py b/tests/graphs/test_graph.py
new file mode 100644
index 0000000..1fbe18b
--- /dev/null
+++ b/tests/graphs/test_graph.py
@@ -0,0 +1,16 @@
+from plesna.graph import Edge, Graph, Node
+
+
+def test_init():
+    nodeA = Node(name="A")
+    nodeB = Node(name="B")
+    nodeC = Node(name="C")
+
+    edge1 = Edge(arrow_name="arrow", source=nodeA, target=nodeC)
+    edge2 = Edge(arrow_name="arrow", source=nodeB, target=nodeC)
+
+    graph = Graph()
+    graph.append(edge1)
+    graph.append(edge2)
+
+    assert graph.nodes == {nodeA, nodeB, nodeC}