diff --git a/CHANGELOG.md b/CHANGELOG.md
index 11722a95..6fd54d97 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -11,6 +11,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - `PageSource` parameter to `CadenzaClient#show`
 - `expandNavigator` option for `CadenzaClient#show` and `CadenzaClient#showMap`
 
+### Fixed
+- Included missing `sandbox.cjs` in npm package.
+
 ## 1.2.0 - 2023-11-08
 ### Added
 - `CadenzaClient#fetchData`
diff --git a/package.json b/package.json
index 976014d1..24a9657a 100644
--- a/package.json
+++ b/package.json
@@ -11,6 +11,7 @@
     "cadenza.js",
     "cadenza.d.ts",
     "CHANGELOG.md",
+    "sandbox.cjs",
     "sandbox.html"
   ],
   "scripts": {