diff --git a/cedar-policy/src/ffi/is_authorized.rs b/cedar-policy/src/ffi/is_authorized.rs
index 990faf8bc..135b1ca5a 100644
--- a/cedar-policy/src/ffi/is_authorized.rs
+++ b/cedar-policy/src/ffi/is_authorized.rs
@@ -223,6 +223,7 @@ impl Diagnostics {
 #[serde(rename_all = "camelCase")]
 pub struct AuthorizationError {
     /// Id of the policy where the error (or warning) occurred
+    #[cfg_attr(feature = "wasm", tsify(type = "string"))]
     pub policy_id: PolicyId,
     /// Error (or warning).
     /// You can look at the `severity` field to see whether it is actually an
diff --git a/cedar-policy/src/ffi/validate.rs b/cedar-policy/src/ffi/validate.rs
index ba31292ef..94bfaa0dd 100644
--- a/cedar-policy/src/ffi/validate.rs
+++ b/cedar-policy/src/ffi/validate.rs
@@ -168,6 +168,7 @@ impl Default for ValidationSettings {
 #[serde(rename_all = "camelCase")]
 pub struct ValidationError {
     /// Id of the policy where the error (or warning) occurred
+    #[cfg_attr(feature = "wasm", tsify(type = "string"))]
     pub policy_id: PolicyId,
     /// Error (or warning) itself.
     /// You can look at the `severity` field to see whether it is actually an