diff --git a/crates/wit-parser/src/lib.rs b/crates/wit-parser/src/lib.rs
index 9d78dda286..696a8c19c3 100644
--- a/crates/wit-parser/src/lib.rs
+++ b/crates/wit-parser/src/lib.rs
@@ -19,7 +19,8 @@ mod live;
 pub use live::LiveTypes;
 mod serde_;
 use serde_::{
-    serialize_anon_result, serialize_id, serialize_id_map, serialize_optional_id, serialize_params,
+    serialize_anon_result, serialize_id, serialize_id_map, serialize_none, serialize_optional_id,
+    serialize_params,
 };
 
 /// Checks if the given string is a legal identifier in wit.
@@ -427,6 +428,7 @@ pub enum TypeOwner {
     Interface(InterfaceId),
     /// This type wasn't inherently defined anywhere, such as a `list<T>`, which
     /// doesn't need an owner.
+    #[serde(untagged, serialize_with = "serialize_none")]
     None,
 }
 
diff --git a/crates/wit-parser/src/serde_.rs b/crates/wit-parser/src/serde_.rs
index 64497b3c96..c31eda8420 100644
--- a/crates/wit-parser/src/serde_.rs
+++ b/crates/wit-parser/src/serde_.rs
@@ -4,6 +4,13 @@ use indexmap::IndexMap;
 use serde::ser::{SerializeMap, SerializeSeq, Serializer};
 use serde::Serialize;
 
+pub fn serialize_none<S>(serializer: S) -> Result<S::Ok, S::Error>
+where
+    S: Serializer,
+{
+    serializer.serialize_none()
+}
+
 pub fn serialize_arena<T, S>(arena: &Arena<T>, serializer: S) -> Result<S::Ok, S::Error>
 where
     T: Serialize,
diff --git a/crates/wit-parser/tests/ui/functions.wit.json b/crates/wit-parser/tests/ui/functions.wit.json
index cac2adb53a..bb2867cde4 100644
--- a/crates/wit-parser/tests/ui/functions.wit.json
+++ b/crates/wit-parser/tests/ui/functions.wit.json
@@ -134,14 +134,14 @@
           ]
         }
       },
-      "owner": "none"
+      "owner": null
     },
     {
       "name": null,
       "kind": {
         "option": "u32"
       },
-      "owner": "none"
+      "owner": null
     },
     {
       "name": null,
@@ -151,7 +151,7 @@
           "err": "float32"
         }
       },
-      "owner": "none"
+      "owner": null
     }
   ],
   "packages": [
diff --git a/crates/wit-parser/tests/ui/random.wit.json b/crates/wit-parser/tests/ui/random.wit.json
index 970e8067f2..5d46664671 100644
--- a/crates/wit-parser/tests/ui/random.wit.json
+++ b/crates/wit-parser/tests/ui/random.wit.json
@@ -49,7 +49,7 @@
       "kind": {
         "list": "u8"
       },
-      "owner": "none"
+      "owner": null
     }
   ],
   "packages": [
diff --git a/crates/wit-parser/tests/ui/resources-empty.wit.json b/crates/wit-parser/tests/ui/resources-empty.wit.json
index 5ec2d76de7..6c40c61dfc 100644
--- a/crates/wit-parser/tests/ui/resources-empty.wit.json
+++ b/crates/wit-parser/tests/ui/resources-empty.wit.json
@@ -48,7 +48,7 @@
           "borrow": 0
         }
       },
-      "owner": "none"
+      "owner": null
     },
     {
       "name": null,
@@ -57,7 +57,7 @@
           "own": 0
         }
       },
-      "owner": "none"
+      "owner": null
     }
   ],
   "packages": [
diff --git a/crates/wit-parser/tests/ui/resources-multiple-returns-borrow.wit.json b/crates/wit-parser/tests/ui/resources-multiple-returns-borrow.wit.json
index 21ed3b10ad..d5fbf02a2c 100644
--- a/crates/wit-parser/tests/ui/resources-multiple-returns-borrow.wit.json
+++ b/crates/wit-parser/tests/ui/resources-multiple-returns-borrow.wit.json
@@ -59,7 +59,7 @@
           "borrow": 0
         }
       },
-      "owner": "none"
+      "owner": null
     }
   ],
   "packages": [
diff --git a/crates/wit-parser/tests/ui/resources-multiple-returns-own.wit.json b/crates/wit-parser/tests/ui/resources-multiple-returns-own.wit.json
index 83ca7fd8b4..e7234f7ed8 100644
--- a/crates/wit-parser/tests/ui/resources-multiple-returns-own.wit.json
+++ b/crates/wit-parser/tests/ui/resources-multiple-returns-own.wit.json
@@ -59,7 +59,7 @@
           "borrow": 0
         }
       },
-      "owner": "none"
+      "owner": null
     },
     {
       "name": null,
@@ -68,7 +68,7 @@
           "own": 0
         }
       },
-      "owner": "none"
+      "owner": null
     }
   ],
   "packages": [
diff --git a/crates/wit-parser/tests/ui/resources-multiple.wit.json b/crates/wit-parser/tests/ui/resources-multiple.wit.json
index f76eb0bccb..b77d35f867 100644
--- a/crates/wit-parser/tests/ui/resources-multiple.wit.json
+++ b/crates/wit-parser/tests/ui/resources-multiple.wit.json
@@ -228,7 +228,7 @@
           "borrow": 0
         }
       },
-      "owner": "none"
+      "owner": null
     },
     {
       "name": null,
@@ -240,14 +240,14 @@
           ]
         }
       },
-      "owner": "none"
+      "owner": null
     },
     {
       "name": null,
       "kind": {
         "option": "u32"
       },
-      "owner": "none"
+      "owner": null
     },
     {
       "name": null,
@@ -257,7 +257,7 @@
           "err": "float32"
         }
       },
-      "owner": "none"
+      "owner": null
     },
     {
       "name": null,
@@ -266,7 +266,7 @@
           "own": 0
         }
       },
-      "owner": "none"
+      "owner": null
     }
   ],
   "packages": [
diff --git a/crates/wit-parser/tests/ui/resources-return-borrow.wit.json b/crates/wit-parser/tests/ui/resources-return-borrow.wit.json
index 85bd1f04fb..c48dd35167 100644
--- a/crates/wit-parser/tests/ui/resources-return-borrow.wit.json
+++ b/crates/wit-parser/tests/ui/resources-return-borrow.wit.json
@@ -54,7 +54,7 @@
           "borrow": 0
         }
       },
-      "owner": "none"
+      "owner": null
     }
   ],
   "packages": [
diff --git a/crates/wit-parser/tests/ui/resources-return-own.wit.json b/crates/wit-parser/tests/ui/resources-return-own.wit.json
index bc3f273263..3e44fc106c 100644
--- a/crates/wit-parser/tests/ui/resources-return-own.wit.json
+++ b/crates/wit-parser/tests/ui/resources-return-own.wit.json
@@ -54,7 +54,7 @@
           "borrow": 0
         }
       },
-      "owner": "none"
+      "owner": null
     },
     {
       "name": null,
@@ -63,7 +63,7 @@
           "own": 0
         }
       },
-      "owner": "none"
+      "owner": null
     }
   ],
   "packages": [
diff --git a/crates/wit-parser/tests/ui/resources.wit.json b/crates/wit-parser/tests/ui/resources.wit.json
index ad368e0679..169fb02110 100644
--- a/crates/wit-parser/tests/ui/resources.wit.json
+++ b/crates/wit-parser/tests/ui/resources.wit.json
@@ -209,7 +209,7 @@
           "borrow": 3
         }
       },
-      "owner": "none"
+      "owner": null
     },
     {
       "name": null,
@@ -218,7 +218,7 @@
           "borrow": 4
         }
       },
-      "owner": "none"
+      "owner": null
     },
     {
       "name": "a",
@@ -286,7 +286,7 @@
           "own": 1
         }
       },
-      "owner": "none"
+      "owner": null
     },
     {
       "name": null,
@@ -295,7 +295,7 @@
           "own": 2
         }
       },
-      "owner": "none"
+      "owner": null
     },
     {
       "name": null,
@@ -304,7 +304,7 @@
           "own": 3
         }
       },
-      "owner": "none"
+      "owner": null
     },
     {
       "name": null,
@@ -313,7 +313,7 @@
           "own": 4
         }
       },
-      "owner": "none"
+      "owner": null
     },
     {
       "name": null,
@@ -322,7 +322,7 @@
           "own": 13
         }
       },
-      "owner": "none"
+      "owner": null
     }
   ],
   "packages": [
diff --git a/crates/wit-parser/tests/ui/resources1.wit.json b/crates/wit-parser/tests/ui/resources1.wit.json
index e04fa4019d..447e5ec2b9 100644
--- a/crates/wit-parser/tests/ui/resources1.wit.json
+++ b/crates/wit-parser/tests/ui/resources1.wit.json
@@ -72,7 +72,7 @@
           "borrow": 0
         }
       },
-      "owner": "none"
+      "owner": null
     },
     {
       "name": null,
@@ -81,7 +81,7 @@
           "own": 0
         }
       },
-      "owner": "none"
+      "owner": null
     }
   ],
   "packages": [
diff --git a/crates/wit-parser/tests/ui/shared-types.wit.json b/crates/wit-parser/tests/ui/shared-types.wit.json
index ba3a90c804..d0dba6598c 100644
--- a/crates/wit-parser/tests/ui/shared-types.wit.json
+++ b/crates/wit-parser/tests/ui/shared-types.wit.json
@@ -57,7 +57,7 @@
       "kind": {
         "list": "u8"
       },
-      "owner": "none"
+      "owner": null
     },
     {
       "name": null,
@@ -68,7 +68,7 @@
           ]
         }
       },
-      "owner": "none"
+      "owner": null
     }
   ],
   "packages": [
diff --git a/crates/wit-parser/tests/ui/types.wit.json b/crates/wit-parser/tests/ui/types.wit.json
index f805f579db..2839365bc8 100644
--- a/crates/wit-parser/tests/ui/types.wit.json
+++ b/crates/wit-parser/tests/ui/types.wit.json
@@ -531,7 +531,7 @@
       "kind": {
         "option": "u32"
       },
-      "owner": "none"
+      "owner": null
     },
     {
       "name": "t37",
@@ -618,14 +618,14 @@
       "kind": {
         "list": 31
       },
-      "owner": "none"
+      "owner": null
     },
     {
       "name": null,
       "kind": {
         "list": 42
       },
-      "owner": "none"
+      "owner": null
     },
     {
       "name": "t45",
diff --git a/crates/wit-parser/tests/ui/world-top-level-funcs.wit.json b/crates/wit-parser/tests/ui/world-top-level-funcs.wit.json
index 7a802a66b3..b7866aa12d 100644
--- a/crates/wit-parser/tests/ui/world-top-level-funcs.wit.json
+++ b/crates/wit-parser/tests/ui/world-top-level-funcs.wit.json
@@ -57,21 +57,21 @@
       "kind": {
         "list": "u32"
       },
-      "owner": "none"
+      "owner": null
     },
     {
       "name": null,
       "kind": {
         "option": "u32"
       },
-      "owner": "none"
+      "owner": null
     },
     {
       "name": null,
       "kind": {
         "list": 1
       },
-      "owner": "none"
+      "owner": null
     }
   ],
   "packages": [
diff --git a/crates/wit-parser/tests/ui/world-top-level-resources.wit.json b/crates/wit-parser/tests/ui/world-top-level-resources.wit.json
index f3e2ff0363..ee1fd2c6f6 100644
--- a/crates/wit-parser/tests/ui/world-top-level-resources.wit.json
+++ b/crates/wit-parser/tests/ui/world-top-level-resources.wit.json
@@ -152,14 +152,14 @@
           "borrow": 0
         }
       },
-      "owner": "none"
+      "owner": null
     },
     {
       "name": null,
       "kind": {
         "list": "u32"
       },
-      "owner": "none"
+      "owner": null
     },
     {
       "name": null,
@@ -168,7 +168,7 @@
           "borrow": 1
         }
       },
-      "owner": "none"
+      "owner": null
     },
     {
       "name": "request",
@@ -195,7 +195,7 @@
           "borrow": 5
         }
       },
-      "owner": "none"
+      "owner": null
     },
     {
       "name": null,
@@ -204,7 +204,7 @@
           "borrow": 6
         }
       },
-      "owner": "none"
+      "owner": null
     },
     {
       "name": null,
@@ -213,7 +213,7 @@
           "own": 5
         }
       },
-      "owner": "none"
+      "owner": null
     },
     {
       "name": null,
@@ -222,7 +222,7 @@
           "own": 6
         }
       },
-      "owner": "none"
+      "owner": null
     }
   ],
   "packages": [