diff --git a/.eslintrc.json b/.eslintrc.json
index ad06ff05..3ad61648 100644
--- a/.eslintrc.json
+++ b/.eslintrc.json
@@ -110,13 +110,7 @@
         {
             "files": [
                 "ext/js/core.js",
-                "ext/js/data/anki-note-data-creator.js",
-                "ext/js/display/pronunciation-generator.js",
-                "ext/js/display/structured-content-generator.js",
-                "ext/js/dom/css-style-applier.js",
-                "ext/js/language/dictionary-data-util.js",
-                "ext/js/templates/template-renderer.js",
-                "ext/js/templates/template-renderer-media-provider.js"
+                "ext/js/**/sandbox/**/*.js"
             ],
             "env": {
                 "webextensions": false
@@ -126,13 +120,7 @@
             "files": ["ext/**/*.js"],
             "excludedFiles": [
                 "ext/js/core.js",
-                "ext/js/data/anki-note-data-creator.js",
-                "ext/js/display/pronunciation-generator.js",
-                "ext/js/display/structured-content-generator.js",
-                "ext/js/dom/css-style-applier.js",
-                "ext/js/language/dictionary-data-util.js",
-                "ext/js/templates/template-renderer.js",
-                "ext/js/templates/template-renderer-media-provider.js"
+                "ext/js/**/sandbox/**/*.js"
             ],
             "globals": {
                 "serializeError": "readonly",
@@ -159,13 +147,7 @@
             "excludedFiles": [
                 "ext/js/core.js",
                 "ext/js/yomichan.js",
-                "ext/js/data/anki-note-data-creator.js",
-                "ext/js/display/pronunciation-generator.js",
-                "ext/js/display/structured-content-generator.js",
-                "ext/js/dom/css-style-applier.js",
-                "ext/js/language/dictionary-data-util.js",
-                "ext/js/templates/template-renderer.js",
-                "ext/js/templates/template-renderer-media-provider.js"
+                "ext/js/**/sandbox/**/*.js"
             ],
             "globals": {
                 "yomichan": "readonly"
@@ -217,9 +199,9 @@
                 "ext/js/general/regex-util.js",
                 "ext/js/general/text-source-map.js",
                 "ext/js/language/deinflector.js",
-                "ext/js/language/dictionary-data-util.js",
                 "ext/js/language/dictionary-database.js",
-                "ext/js/language/japanese-util.js",
+                "ext/js/language/sandbox/dictionary-data-util.js",
+                "ext/js/language/sandbox/japanese-util.js",
                 "ext/js/language/translator.js",
                 "ext/js/media/audio-downloader.js",
                 "ext/js/media/media-util.js",
diff --git a/dev/translator-vm.js b/dev/translator-vm.js
index d628608a..742036a8 100644
--- a/dev/translator-vm.js
+++ b/dev/translator-vm.js
@@ -45,17 +45,17 @@ class TranslatorVM extends DatabaseVM {
     async prepare(dictionaryDirectory, dictionaryName) {
         this.execute([
             'js/core.js',
-            'js/data/anki-note-data-creator.js',
+            'js/data/sandbox/anki-note-data-creator.js',
             'js/data/database.js',
             'js/data/json-schema.js',
             'js/general/cache-map.js',
             'js/general/regex-util.js',
             'js/general/text-source-map.js',
             'js/language/deinflector.js',
-            'js/language/dictionary-data-util.js',
+            'js/language/sandbox/dictionary-data-util.js',
             'js/language/dictionary-importer.js',
             'js/language/dictionary-database.js',
-            'js/language/japanese-util.js',
+            'js/language/sandbox/japanese-util.js',
             'js/language/translator.js',
             'js/media/media-util.js'
         ]);
diff --git a/docs/templates.md b/docs/templates.md
index 28878c87..8ee3bb0c 100644
--- a/docs/templates.md
+++ b/docs/templates.md
@@ -3,7 +3,7 @@
 ## Helpers
 
 Yomichan supports several custom Handlebars helpers for rendering templates.
-The source code for these templates can be found [here](../ext/js/templates/template-renderer.js).
+The source code for these templates can be found [here](../ext/js/templates/sandbox/template-renderer.js).
 
 
 ### `dumpObject`
diff --git a/ext/background.html b/ext/background.html
index 15cd0b8c..57caa671 100644
--- a/ext/background.html
+++ b/ext/background.html
@@ -42,9 +42,9 @@
 <script src="/js/general/regex-util.js"></script>
 <script src="/js/general/text-source-map.js"></script>
 <script src="/js/language/deinflector.js"></script>
-<script src="/js/language/dictionary-data-util.js"></script>
 <script src="/js/language/dictionary-database.js"></script>
-<script src="/js/language/japanese-util.js"></script>
+<script src="/js/language/sandbox/dictionary-data-util.js"></script>
+<script src="/js/language/sandbox/japanese-util.js"></script>
 <script src="/js/language/translator.js"></script>
 <script src="/js/media/audio-downloader.js"></script>
 <script src="/js/media/media-util.js"></script>
diff --git a/ext/js/data/anki-note-data-creator.js b/ext/js/data/sandbox/anki-note-data-creator.js
similarity index 100%
rename from ext/js/data/anki-note-data-creator.js
rename to ext/js/data/sandbox/anki-note-data-creator.js
diff --git a/ext/js/display/pronunciation-generator.js b/ext/js/display/sandbox/pronunciation-generator.js
similarity index 100%
rename from ext/js/display/pronunciation-generator.js
rename to ext/js/display/sandbox/pronunciation-generator.js
diff --git a/ext/js/display/structured-content-generator.js b/ext/js/display/sandbox/structured-content-generator.js
similarity index 100%
rename from ext/js/display/structured-content-generator.js
rename to ext/js/display/sandbox/structured-content-generator.js
diff --git a/ext/js/dom/css-style-applier.js b/ext/js/dom/sandbox/css-style-applier.js
similarity index 100%
rename from ext/js/dom/css-style-applier.js
rename to ext/js/dom/sandbox/css-style-applier.js
diff --git a/ext/js/language/dictionary-data-util.js b/ext/js/language/sandbox/dictionary-data-util.js
similarity index 100%
rename from ext/js/language/dictionary-data-util.js
rename to ext/js/language/sandbox/dictionary-data-util.js
diff --git a/ext/js/language/japanese-util.js b/ext/js/language/sandbox/japanese-util.js
similarity index 100%
rename from ext/js/language/japanese-util.js
rename to ext/js/language/sandbox/japanese-util.js
diff --git a/ext/js/templates/template-renderer-frame-api.js b/ext/js/templates/sandbox/template-renderer-frame-api.js
similarity index 100%
rename from ext/js/templates/template-renderer-frame-api.js
rename to ext/js/templates/sandbox/template-renderer-frame-api.js
diff --git a/ext/js/templates/template-renderer-frame-main.js b/ext/js/templates/sandbox/template-renderer-frame-main.js
similarity index 100%
rename from ext/js/templates/template-renderer-frame-main.js
rename to ext/js/templates/sandbox/template-renderer-frame-main.js
diff --git a/ext/js/templates/template-renderer-media-provider.js b/ext/js/templates/sandbox/template-renderer-media-provider.js
similarity index 100%
rename from ext/js/templates/template-renderer-media-provider.js
rename to ext/js/templates/sandbox/template-renderer-media-provider.js
diff --git a/ext/js/templates/template-renderer.js b/ext/js/templates/sandbox/template-renderer.js
similarity index 100%
rename from ext/js/templates/template-renderer.js
rename to ext/js/templates/sandbox/template-renderer.js
diff --git a/ext/popup.html b/ext/popup.html
index 065bcfa1..1f336943 100644
--- a/ext/popup.html
+++ b/ext/popup.html
@@ -110,9 +110,9 @@
 <script src="/js/display/display-resizer.js"></script>
 <script src="/js/display/element-overflow-controller.js"></script>
 <script src="/js/display/option-toggle-hotkey-handler.js"></script>
-<script src="/js/display/pronunciation-generator.js"></script>
 <script src="/js/display/query-parser.js"></script>
-<script src="/js/display/structured-content-generator.js"></script>
+<script src="/js/display/sandbox/pronunciation-generator.js"></script>
+<script src="/js/display/sandbox/structured-content-generator.js"></script>
 <script src="/js/dom/document-focus-controller.js"></script>
 <script src="/js/dom/document-util.js"></script>
 <script src="/js/dom/dom-text-scanner.js"></script>
@@ -125,8 +125,8 @@
 <script src="/js/input/hotkey-handler.js"></script>
 <script src="/js/input/hotkey-help-controller.js"></script>
 <script src="/js/input/hotkey-util.js"></script>
-<script src="/js/language/dictionary-data-util.js"></script>
-<script src="/js/language/japanese-util.js"></script>
+<script src="/js/language/sandbox/dictionary-data-util.js"></script>
+<script src="/js/language/sandbox/japanese-util.js"></script>
 <script src="/js/language/text-scanner.js"></script>
 <script src="/js/media/audio-system.js"></script>
 <script src="/js/media/media-loader.js"></script>
diff --git a/ext/search.html b/ext/search.html
index beceeb18..f32b5412 100644
--- a/ext/search.html
+++ b/ext/search.html
@@ -94,12 +94,12 @@
 <script src="/js/display/display-notification.js"></script>
 <script src="/js/display/element-overflow-controller.js"></script>
 <script src="/js/display/option-toggle-hotkey-handler.js"></script>
-<script src="/js/display/pronunciation-generator.js"></script>
 <script src="/js/display/query-parser.js"></script>
+<script src="/js/display/sandbox/pronunciation-generator.js"></script>
+<script src="/js/display/sandbox/structured-content-generator.js"></script>
 <script src="/js/display/search-action-popup-controller.js"></script>
 <script src="/js/display/search-display-controller.js"></script>
 <script src="/js/display/search-persistent-state-controller.js"></script>
-<script src="/js/display/structured-content-generator.js"></script>
 <script src="/js/dom/document-focus-controller.js"></script>
 <script src="/js/dom/document-util.js"></script>
 <script src="/js/dom/dom-text-scanner.js"></script>
@@ -111,8 +111,8 @@
 <script src="/js/input/hotkey-handler.js"></script>
 <script src="/js/input/hotkey-help-controller.js"></script>
 <script src="/js/input/hotkey-util.js"></script>
-<script src="/js/language/dictionary-data-util.js"></script>
-<script src="/js/language/japanese-util.js"></script>
+<script src="/js/language/sandbox/dictionary-data-util.js"></script>
+<script src="/js/language/sandbox/japanese-util.js"></script>
 <script src="/js/language/text-scanner.js"></script>
 <script src="/js/media/audio-system.js"></script>
 <script src="/js/media/media-loader.js"></script>
diff --git a/ext/settings.html b/ext/settings.html
index b45d8c22..9d2d9791 100644
--- a/ext/settings.html
+++ b/ext/settings.html
@@ -3449,10 +3449,10 @@
 <script src="/js/general/object-property-accessor.js"></script>
 <script src="/js/general/task-accumulator.js"></script>
 <script src="/js/input/hotkey-util.js"></script>
-<script src="/js/language/dictionary-data-util.js"></script>
 <script src="/js/language/dictionary-database.js"></script>
 <script src="/js/language/dictionary-importer.js"></script>
-<script src="/js/language/japanese-util.js"></script>
+<script src="/js/language/sandbox/dictionary-data-util.js"></script>
+<script src="/js/language/sandbox/japanese-util.js"></script>
 <script src="/js/media/audio-system.js"></script>
 <script src="/js/media/media-util.js"></script>
 <script src="/js/media/text-to-speech-audio.js"></script>
diff --git a/ext/sw.js b/ext/sw.js
index a1fb7ea1..6394260e 100644
--- a/ext/sw.js
+++ b/ext/sw.js
@@ -39,9 +39,9 @@ self.importScripts(
     '/js/general/regex-util.js',
     '/js/general/text-source-map.js',
     '/js/language/deinflector.js',
-    '/js/language/dictionary-data-util.js',
     '/js/language/dictionary-database.js',
-    '/js/language/japanese-util.js',
+    '/js/language/sandbox/dictionary-data-util.js',
+    '/js/language/sandbox/japanese-util.js',
     '/js/language/translator.js',
     '/js/media/audio-downloader.js',
     '/js/media/media-util.js',
diff --git a/ext/template-renderer.html b/ext/template-renderer.html
index a3812b37..9e0769f9 100644
--- a/ext/template-renderer.html
+++ b/ext/template-renderer.html
@@ -17,16 +17,16 @@
 <!-- Scripts -->
 <script src="/lib/handlebars.min.js"></script>
 
-<script src="/js/data/anki-note-data-creator.js"></script>
-<script src="/js/display/structured-content-generator.js"></script>
-<script src="/js/dom/css-style-applier.js"></script>
-<script src="/js/language/dictionary-data-util.js"></script>
-<script src="/js/language/japanese-util.js"></script>
-<script src="/js/templates/template-renderer.js"></script>
-<script src="/js/templates/template-renderer-frame-api.js"></script>
-<script src="/js/templates/template-renderer-media-provider.js"></script>
+<script src="/js/data/sandbox/anki-note-data-creator.js"></script>
+<script src="/js/display/sandbox/structured-content-generator.js"></script>
+<script src="/js/dom/sandbox/css-style-applier.js"></script>
+<script src="/js/language/sandbox/dictionary-data-util.js"></script>
+<script src="/js/language/sandbox/japanese-util.js"></script>
+<script src="/js/templates/sandbox/template-renderer.js"></script>
+<script src="/js/templates/sandbox/template-renderer-frame-api.js"></script>
+<script src="/js/templates/sandbox/template-renderer-media-provider.js"></script>
 
-<script src="/js/templates/template-renderer-frame-main.js"></script>
+<script src="/js/templates/sandbox/template-renderer-frame-main.js"></script>
 
 </body>
 </html>
diff --git a/test/test-anki-note-builder.js b/test/test-anki-note-builder.js
index 4433e3e6..d6b41c3b 100644
--- a/test/test-anki-note-builder.js
+++ b/test/test-anki-note-builder.js
@@ -43,10 +43,10 @@ async function createVM() {
     vm.execute([
         'js/data/anki-note-builder.js',
         'js/data/anki-util.js',
-        'js/dom/css-style-applier.js',
-        'js/display/structured-content-generator.js',
-        'js/templates/template-renderer.js',
-        'js/templates/template-renderer-media-provider.js',
+        'js/dom/sandbox/css-style-applier.js',
+        'js/display/sandbox/structured-content-generator.js',
+        'js/templates/sandbox/template-renderer.js',
+        'js/templates/sandbox/template-renderer-media-provider.js',
         'lib/handlebars.min.js'
     ]);
 
diff --git a/test/test-japanese-util.js b/test/test-japanese-util.js
index 82abf50b..bfeac4f5 100644
--- a/test/test-japanese-util.js
+++ b/test/test-japanese-util.js
@@ -22,7 +22,7 @@ const {VM} = require('../dev/vm');
 const vm = new VM();
 vm.execute([
     'lib/wanakana.min.js',
-    'js/language/japanese-util.js',
+    'js/language/sandbox/japanese-util.js',
     'js/general/text-source-map.js'
 ]);
 const [JapaneseUtil, TextSourceMap, wanakana] = vm.get(['JapaneseUtil', 'TextSourceMap', 'wanakana']);