diff --git a/playground/chart_api.py b/playground/chart_api.py
new file mode 100644
index 0000000..9e3f55c
--- /dev/null
+++ b/playground/chart_api.py
@@ -0,0 +1,49 @@
+# Use fastapi to create Chart object below
+
+from fastapi import FastAPI
+from pydantic import BaseModel
+from core import T5
+
+app = FastAPI()
+
+
+class FastChart(BaseModel):
+    income_summary_account: str
+    retained_earnings_account: str
+    accounts: dict[str, tuple[T5, list[str]]]
+
+
+class ChartRequest(BaseModel):
+    pass
+
+
+@app.post("/chart/new")
+def create_chart(
+    income_summary_account: str = "isa", retained_earnings_account: str = "re"
+) -> FastChart:
+    return FastChart(
+        income_summary_account=income_summary_account,
+        retained_earnings_account=retained_earnings_account,
+        accounts={retained_earnings_account: (T5.Capital, [])},
+    )
+
+from fastapi.testclient import TestClient
+
+client = TestClient(app)
+
+def test_chart_new():
+    payload = {
+        "income_summary_account": "current_profit",
+        "retained_earnings_account": "retained_earnings",
+    }
+    response = client.post("/chart/new", params=payload)
+    assert response.status_code == 200
+    assert response.json() == {
+        "income_summary_account": "current_profit",
+        "retained_earnings_account": "retained_earnings",
+        "accounts": {"retained_earnings": ["capital", []]},
+    }
+
+
+test_chart_new()
+print(create_chart())
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