diff --git a/backend/src/app/api/mii/[id]/info/route.ts b/backend/src/app/api/mii/[id]/info/route.ts
index ca7f102..a97f617 100644
--- a/backend/src/app/api/mii/[id]/info/route.ts
+++ b/backend/src/app/api/mii/[id]/info/route.ts
@@ -34,5 +34,7 @@ export async function GET(request: NextRequest, { params }: { params: Promise<{
 		},
 	});
 
+	if (!mii) return NextResponse.json({ error: "Mii not found" }, { status: 404 });
+
 	return NextResponse.json(mii);
 }
diff --git a/backend/src/app/api/profile/[id]/info/route.ts b/backend/src/app/api/profile/[id]/info/route.ts
index 410d30d..792b2e4 100644
--- a/backend/src/app/api/profile/[id]/info/route.ts
+++ b/backend/src/app/api/profile/[id]/info/route.ts
@@ -21,5 +21,7 @@ export async function GET(request: NextRequest, { params }: { params: Promise<{
 		},
 	});
 
+	if (!user) return NextResponse.json({ error: "User not found" }, { status: 404 });
+
 	return NextResponse.json(user);
 }
diff --git a/frontend/src/pages/mii.tsx b/frontend/src/pages/mii.tsx
index 096b894..232a9bc 100644
--- a/frontend/src/pages/mii.tsx
+++ b/frontend/src/pages/mii.tsx
@@ -31,6 +31,8 @@ export default function MiiPage() {
 				return res.json();
 			})
 			.then((data) => {
+				if (!data) throw new Error("Mii not found");
+
 				setMii(data);
 				setLoading(false);
 
diff --git a/frontend/src/pages/profile/layout.tsx b/frontend/src/pages/profile/layout.tsx
index 23265eb..25b20a0 100644
--- a/frontend/src/pages/profile/layout.tsx
+++ b/frontend/src/pages/profile/layout.tsx
@@ -28,6 +28,8 @@ export default function ProfileLayout() {
 				return res.json();
 			})
 			.then((data) => {
+				if (!data) throw new Error("Profile not found");
+
 				setUser(data);
 				setLoading(false);
 			})