diff --git a/enro-common/src/androidMain/kotlin/dev/enro/metadataKeyName.android.kt b/enro-common/src/androidMain/kotlin/dev/enro/metadataKeyName.android.kt
new file mode 100644
index 00000000..e33ec857
--- /dev/null
+++ b/enro-common/src/androidMain/kotlin/dev/enro/metadataKeyName.android.kt
@@ -0,0 +1,9 @@
+package dev.enro
+
+import kotlin.reflect.KClass
+
+internal actual fun metadataKeyName(kClass: KClass<*>): String {
+    return kClass.qualifiedName
+        ?: kClass.simpleName
+        ?: error("MetadataKey class must have a qualifiedName or simpleName")
+}
diff --git a/enro-common/src/commonMain/kotlin/dev/enro/NavigationKey.kt b/enro-common/src/commonMain/kotlin/dev/enro/NavigationKey.kt
index c2760cf0..0f01b954 100644
--- a/enro-common/src/commonMain/kotlin/dev/enro/NavigationKey.kt
+++ b/enro-common/src/commonMain/kotlin/dev/enro/NavigationKey.kt
@@ -224,7 +224,7 @@ public interface NavigationKey {
         public val default: T,
     ) {
         public val name: String by lazy {
-            this::class.qualifiedName ?: error("MetadataKeys must have a valid qualifiedName")
+            metadataKeyName(this::class)
         }
     }
 
diff --git a/enro-common/src/commonMain/kotlin/dev/enro/metadataKeyName.kt b/enro-common/src/commonMain/kotlin/dev/enro/metadataKeyName.kt
new file mode 100644
index 00000000..311f7b74
--- /dev/null
+++ b/enro-common/src/commonMain/kotlin/dev/enro/metadataKeyName.kt
@@ -0,0 +1,21 @@
+package dev.enro
+
+import kotlin.reflect.KClass
+
+/**
+ * Stable string identifier for a [NavigationKey.MetadataKey]'s class.
+ * Used as the storage key inside [NavigationKey.Metadata] and persisted
+ * across saved-state round-trips, so the identifier must be:
+ *
+ * - **Stable across runs** — serialised metadata must restore to the
+ *   same logical key on next launch.
+ * - **Unique per MetadataKey class** — two different MetadataKey objects
+ *   must not collide.
+ *
+ * On every target except Kotlin/JS this is `KClass.qualifiedName`. On
+ * Kotlin/JS, `qualifiedName` is unsupported by the Kotlin reflection
+ * API, so we fall back to `simpleName`. The JS fallback is correct for
+ * the common `object MyKey : MetadataKey<...>` pattern as long as the
+ * `MyKey` simple names are unique within the app.
+ */
+internal expect fun metadataKeyName(kClass: KClass<*>): String
diff --git a/enro-common/src/desktopMain/kotlin/dev/enro/metadataKeyName.desktop.kt b/enro-common/src/desktopMain/kotlin/dev/enro/metadataKeyName.desktop.kt
new file mode 100644
index 00000000..e33ec857
--- /dev/null
+++ b/enro-common/src/desktopMain/kotlin/dev/enro/metadataKeyName.desktop.kt
@@ -0,0 +1,9 @@
+package dev.enro
+
+import kotlin.reflect.KClass
+
+internal actual fun metadataKeyName(kClass: KClass<*>): String {
+    return kClass.qualifiedName
+        ?: kClass.simpleName
+        ?: error("MetadataKey class must have a qualifiedName or simpleName")
+}
diff --git a/enro-common/src/iosMain/kotlin/dev/enro/metadataKeyName.ios.kt b/enro-common/src/iosMain/kotlin/dev/enro/metadataKeyName.ios.kt
new file mode 100644
index 00000000..e33ec857
--- /dev/null
+++ b/enro-common/src/iosMain/kotlin/dev/enro/metadataKeyName.ios.kt
@@ -0,0 +1,9 @@
+package dev.enro
+
+import kotlin.reflect.KClass
+
+internal actual fun metadataKeyName(kClass: KClass<*>): String {
+    return kClass.qualifiedName
+        ?: kClass.simpleName
+        ?: error("MetadataKey class must have a qualifiedName or simpleName")
+}
diff --git a/enro-common/src/jsMain/kotlin/dev/enro/metadataKeyName.js.kt b/enro-common/src/jsMain/kotlin/dev/enro/metadataKeyName.js.kt
new file mode 100644
index 00000000..95837709
--- /dev/null
+++ b/enro-common/src/jsMain/kotlin/dev/enro/metadataKeyName.js.kt
@@ -0,0 +1,12 @@
+package dev.enro
+
+import kotlin.reflect.KClass
+
+// Kotlin/JS reflection does not expose qualifiedName. simpleName is the
+// only stable identifier available — collisions across packages are
+// possible in principle, but the recommended `object MyKey : MetadataKey<…>`
+// pattern produces a unique simpleName per definition site.
+internal actual fun metadataKeyName(kClass: KClass<*>): String {
+    return kClass.simpleName
+        ?: error("MetadataKey class must have a simpleName on Kotlin/JS")
+}
diff --git a/enro-common/src/wasmJsMain/kotlin/dev/enro/metadataKeyName.wasmJs.kt b/enro-common/src/wasmJsMain/kotlin/dev/enro/metadataKeyName.wasmJs.kt
new file mode 100644
index 00000000..e33ec857
--- /dev/null
+++ b/enro-common/src/wasmJsMain/kotlin/dev/enro/metadataKeyName.wasmJs.kt
@@ -0,0 +1,9 @@
+package dev.enro
+
+import kotlin.reflect.KClass
+
+internal actual fun metadataKeyName(kClass: KClass<*>): String {
+    return kClass.qualifiedName
+        ?: kClass.simpleName
+        ?: error("MetadataKey class must have a qualifiedName or simpleName")
+}