diff --git a/lib/open_api_spex/cast.ex b/lib/open_api_spex/cast.ex
index f8a97a54..7d24e524 100644
--- a/lib/open_api_spex/cast.ex
+++ b/lib/open_api_spex/cast.ex
@@ -170,6 +170,13 @@ defmodule OpenApiSpex.Cast do
   def cast(%__MODULE__{schema: %{type: :array}} = ctx),
     do: Array.cast(ctx)
 
+  # Explicit nil types are considered as wildcards, as in
+  # properties
+  #   value: {}
+  # See  https://json-schema.org/understanding-json-schema/basics.html#id1
+  def cast(%__MODULE__{schema: %{type: nil}, value: value} = _ctx),
+    do: {:ok, value}
+
   def cast(%__MODULE__{schema: %{type: _other}} = ctx),
     do: error(ctx, {:invalid_schema_type})
 
diff --git a/test/cast_test.exs b/test/cast_test.exs
index 0fcc1075..82542d35 100644
--- a/test/cast_test.exs
+++ b/test/cast_test.exs
@@ -12,9 +12,7 @@ defmodule OpenApiSpec.CastTest do
       assert error.reason == :invalid_schema_type
       assert error.type == :nope
 
-      assert {:error, [error]} = cast(value: "string", schema: %Schema{type: nil})
-      assert error.reason == :invalid_schema_type
-      assert error.type == nil
+      assert {:ok, "string"} = cast(value: "string", schema: %Schema{type: nil})
     end
 
     # Note: full tests for primitives are covered in Cast.PrimitiveTest