diff --git a/README.ja.md b/README.ja.md
index 0a09bed..6e5f993 100644
--- a/README.ja.md
+++ b/README.ja.md
@@ -20,7 +20,7 @@ Glendix は Marketplace やブラウザ自動化を実装しません。
 
 ```toml
 [dependencies]
-glendix = ">= 5.1.0 and < 6.0.0"
+glendix = ">= 6.0.0 and < 7.0.0"
 ```
 
 Mendix クライアント値または MPK コンポーネントが必要な場合だけ `mendraw`、
@@ -219,6 +219,15 @@ JavaScript 設定、最終 MPK ビルドを担当します。
 | `gleam run -m glendix/lint_fix` | lint 修正 |
 | `gleam run -m glendix/release` | release ビルド |
 
+## 6.0.0 の破壊的変更
+
+`glendix/js/array` は変換を `gleam/javascript/array` に委譲するようになり、手書き
+の JavaScript アダプターを同梱しなくなりました。`from_list` と `to_list` は関数
+名・ラベル・要素順序の挙動を維持するため、一般的な
+`list |> array.from_list |> array.to_list` の利用方法は変わりません。従来の
+opaque 型 `glendix/js/array.JsArray(element)` は削除されたので、値の型は
+`gleam/javascript/array.Array(element)` で注釈してください。
+
 ## 開発
 
 ```sh
diff --git a/README.ko.md b/README.ko.md
index ee6e75d..378fece 100644
--- a/README.ko.md
+++ b/README.ko.md
@@ -19,7 +19,7 @@ Glendix는 Marketplace나 브라우저 자동화를 구현하지 않는다.
 
 ```toml
 [dependencies]
-glendix = ">= 5.1.0 and < 6.0.0"
+glendix = ">= 6.0.0 and < 7.0.0"
 ```
 
 Mendix 클라이언트 값이나 MPK 컴포넌트가 필요할 때만 `mendraw`를 추가하고,
@@ -215,6 +215,15 @@ JavaScript 설정, 최종 MPK 빌드를 담당한다. Marketplace 위젯을 쓰
 | `gleam run -m glendix/lint_fix` | lint 수정 |
 | `gleam run -m glendix/release` | release 빌드 |
 
+## 6.0.0 호환성 변경
+
+`glendix/js/array`는 이제 변환을 `gleam/javascript/array`에 위임하며 수기
+JavaScript 어댑터를 더 이상 포함하지 않는다. `from_list`와 `to_list`는 함수
+이름·label·원소 순서 동작을 그대로 유지하므로 일반적인
+`list |> array.from_list |> array.to_list` 사용은 변경되지 않는다. 기존 opaque
+타입 `glendix/js/array.JsArray(element)`는 제거되었으므로 값의 타입은
+`gleam/javascript/array.Array(element)`로 표기한다.
+
 ## 개발
 
 ```sh
diff --git a/README.md b/README.md
index 8bb9a59..34a773f 100644
--- a/README.md
+++ b/README.md
@@ -21,7 +21,7 @@ Glendix does not implement Marketplace access or browser automation.
 
 ```toml
 [dependencies]
-glendix = ">= 5.1.0 and < 6.0.0"
+glendix = ">= 6.0.0 and < 7.0.0"
 ```
 
 Add `mendraw` only when the project uses Mendix client values or installed MPK
@@ -282,6 +282,15 @@ Projects that do not use Marketplace widgets omit the first two steps.
 | `gleam run -m glendix/lint_fix` | Apply lint fixes |
 | `gleam run -m glendix/release` | Run the release build |
 
+## Breaking changes in 6.0.0
+
+`glendix/js/array` now delegates its conversions to `gleam/javascript/array`
+and no longer ships a handwritten JavaScript adapter. The `from_list` and
+`to_list` functions keep their names, labels, and element-order behavior, so the
+common `list |> array.from_list |> array.to_list` usage is unchanged. The former
+opaque `glendix/js/array.JsArray(element)` type is removed; annotate values with
+`gleam/javascript/array.Array(element)` instead.
+
 ## Development
 
 ```sh
diff --git a/gleam.toml b/gleam.toml
index d2a2cc6..e383e6e 100644
--- a/gleam.toml
+++ b/gleam.toml
@@ -1,5 +1,5 @@
 name = "glendix"
-version = "5.1.0"
+version = "6.0.0"
 gleam = ">= 1.17.0"
 target = "javascript"
 description = "Mendix widget build tooling with external React bindings and a Lustre bridge"
diff --git a/glendix_guide.ja.md b/glendix_guide.ja.md
index 8efc1e6..19edc45 100644
--- a/glendix_guide.ja.md
+++ b/glendix_guide.ja.md
@@ -20,7 +20,7 @@ Glendix は Marketplace やブラウザ自動化を実装しません。
 
 ```toml
 [dependencies]
-glendix = ">= 5.1.0 and < 6.0.0"
+glendix = ">= 6.0.0 and < 7.0.0"
 ```
 
 Mendix クライアント値または MPK コンポーネントが必要な場合だけ `mendraw`、
diff --git a/glendix_guide.ko.md b/glendix_guide.ko.md
index 6811d85..acecff3 100644
--- a/glendix_guide.ko.md
+++ b/glendix_guide.ko.md
@@ -19,7 +19,7 @@ Glendix는 Marketplace나 브라우저 자동화를 구현하지 않는다.
 
 ```toml
 [dependencies]
-glendix = ">= 5.1.0 and < 6.0.0"
+glendix = ">= 6.0.0 and < 7.0.0"
 ```
 
 Mendix 클라이언트 값이나 MPK 컴포넌트가 필요할 때만 `mendraw`를 추가하고,
diff --git a/glendix_guide.md b/glendix_guide.md
index 905a7db..bd72f72 100644
--- a/glendix_guide.md
+++ b/glendix_guide.md
@@ -21,7 +21,7 @@ Glendix does not implement Marketplace access or browser automation.
 
 ```toml
 [dependencies]
-glendix = ">= 5.1.0 and < 6.0.0"
+glendix = ">= 6.0.0 and < 7.0.0"
 ```
 
 Add `mendraw` only when the project uses Mendix client values or installed MPK
diff --git a/src/glendix/js/array.gleam b/src/glendix/js/array.gleam
index 355be59..304e04d 100644
--- a/src/glendix/js/array.gleam
+++ b/src/glendix/js/array.gleam
@@ -1,22 +1,20 @@
-//// Converts between Gleam lists and JavaScript arrays at the FFI boundary.
+//// Converts between Gleam lists and JavaScript arrays.
+////
+//// The conversions delegate to `gleam/javascript/array`, so the standard
+//// `Array(element)` type is the JavaScript array representation and Glendix no
+//// longer owns equivalent runtime code. The former opaque `JsArray(element)`
+//// type is removed; annotate values with `gleam/javascript/array.Array`
+//// instead. See the repository README for the migration note.
 ////
 
-/// Represents a JavaScript array whose elements have a known Gleam type.
-pub type JsArray(element)
+import gleam/javascript/array as javascript_array
 
-/// Converts a Gleam list into a JavaScript array.
-pub fn from_list(list list: List(element)) -> JsArray(element) {
-  list_to_array(list)
+/// Converts a Gleam list into a JavaScript array, preserving element order.
+pub fn from_list(list list: List(element)) -> javascript_array.Array(element) {
+  javascript_array.from_list(list)
 }
 
-/// Converts a JavaScript array into a Gleam list.
-pub fn to_list(array array: JsArray(element)) -> List(element) {
-  array_to_list(array)
+/// Converts a JavaScript array into a Gleam list, preserving element order.
+pub fn to_list(array array: javascript_array.Array(element)) -> List(element) {
+  javascript_array.to_list(array)
 }
-
-// -- FFI --
-@external(javascript, "./array_ffi.mjs", "list_to_array")
-fn list_to_array(list: List(element)) -> JsArray(element)
-
-@external(javascript, "./array_ffi.mjs", "array_to_list")
-fn array_to_list(array: JsArray(element)) -> List(element)
diff --git a/src/glendix/js/array_ffi.mjs b/src/glendix/js/array_ffi.mjs
deleted file mode 100644
index 66a9747..0000000
--- a/src/glendix/js/array_ffi.mjs
+++ /dev/null
@@ -1,7 +0,0 @@
-import { toList } from "../../gleam.mjs";
-export function list_to_array(list) {
-  return list.toArray();
-}
-export function array_to_list(array) {
-  return toList(array);
-}
diff --git a/test/glendix_test.gleam b/test/glendix_test.gleam
index a4bf82f..5681626 100644
--- a/test/glendix_test.gleam
+++ b/test/glendix_test.gleam
@@ -1,6 +1,7 @@
 //// Exercises Glendix pure domain logic and JavaScript FFI contracts.
 ////
 
+import gleam/javascript/array as javascript_array
 import gleam/javascript/promise
 import gleam/json
 import gleam/list
@@ -217,12 +218,23 @@ pub fn define_failed_file_write_contract_test() -> Nil {
   }
 }
 
-/// Verifies the JavaScript array FFI preserves element order.
-pub fn javascript_array_round_trip_test() -> Nil {
-  [1, 2, 3]
+/// Verifies Int list round trips preserve empty, singleton, and ordered values.
+pub fn javascript_array_int_round_trip_test() -> Nil {
+  let examples = [[], [1], [1, 2, 3]]
+  list.each(examples, fn(example) {
+    let standard_array: javascript_array.Array(Int) = array.from_list(example)
+    standard_array
+    |> array.to_list
+    |> should.equal(example)
+  })
+}
+
+/// Verifies the conversion is generic over the element type.
+pub fn javascript_array_string_round_trip_test() -> Nil {
+  ["glendix", "js", "array"]
   |> array.from_list
   |> array.to_list
-  |> should.equal([1, 2, 3])
+  |> should.equal(["glendix", "js", "array"])
 }
 
 /// Verifies the JavaScript JSON FFI parses and serializes typed JSON values.