diff --git a/cashu/core/base.py b/cashu/core/base.py
index 30db781..00591c8 100644
--- a/cashu/core/base.py
+++ b/cashu/core/base.py
@@ -130,7 +130,7 @@ class GetMeltResponse(BaseModel):
 class SplitRequest(BaseModel):
     proofs: List[Proof]
     amount: int
-    outputs: Union[List[BlindedMessage], None] = None
+    outputs: List[BlindedMessage]
 
 
 class PostSplitResponse(BaseModel):
diff --git a/cashu/mint/router.py b/cashu/mint/router.py
index 5744412..7fce297 100644
--- a/cashu/mint/router.py
+++ b/cashu/mint/router.py
@@ -120,14 +120,11 @@ async def split(
     Requetst a set of tokens with amount "total" to be split into two
     newly minted sets with amount "split" and "total-split".
     """
-    proofs = payload.proofs
-    amount = payload.amount
-
-    outputs = payload.outputs or None
-
-    assert outputs, Exception("no outputs provided.")
+    assert payload.outputs, Exception("no outputs provided.")
     try:
-        split_return = await ledger.split(proofs, amount, outputs)
+        split_return = await ledger.split(
+            payload.proofs, payload.amount, payload.outputs
+        )
     except Exception as exc:
         return CashuError(code=0, error=str(exc))
     if not split_return: