diff --git a/web/app_options.js b/web/app_options.js
new file mode 100644
index 000000000..4325d22df
--- /dev/null
+++ b/web/app_options.js
@@ -0,0 +1,70 @@
+/* Copyright 2018 Mozilla Foundation
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+const OptionKind = {
+  VIEWER: 'viewer',
+  API: 'api',
+  WORKER: 'worker',
+};
+
+/**
+ * PLEASE NOTE: To avoid introducing unnecessary dependencies, we specify the
+ *              values below *explicitly* rather than relying on imported types;
+ *              compare with the format of `default_preferences.json`.
+ */
+const defaultOptions = {
+};
+
+const userOptions = Object.create(null);
+
+class AppOptions {
+  constructor() {
+    throw new Error('Cannot initialize AppOptions.');
+  }
+
+  static get(name) {
+    let defaultOption = defaultOptions[name], userOption = userOptions[name];
+    if (userOption !== undefined) {
+      return userOption;
+    }
+    return (defaultOption !== undefined ? defaultOption.value : undefined);
+  }
+
+  static getAll(kind = null) {
+    let options = Object.create(null);
+    for (let name in defaultOptions) {
+      let defaultOption = defaultOptions[name], userOption = userOptions[name];
+      if (kind && defaultOption.kind !== kind) {
+        continue;
+      }
+      options[name] = (userOption !== undefined ?
+                       userOption : defaultOption.value);
+    }
+    return options;
+  }
+
+  static set(name, value) {
+    userOptions[name] = value;
+  }
+
+  static remove(name) {
+    delete userOptions[name];
+  }
+}
+
+export {
+  AppOptions,
+  OptionKind,
+};
diff --git a/web/viewer.js b/web/viewer.js
index ba680ec65..ecd7bc6cf 100644
--- a/web/viewer.js
+++ b/web/viewer.js
@@ -35,9 +35,10 @@ if (typeof PDFJSDev !== 'undefined' && PDFJSDev.test('CHROME')) {
   })();
 }
 
-let pdfjsWebApp;
+let pdfjsWebApp, pdfjsWebAppOptions;
 if (typeof PDFJSDev !== 'undefined' && PDFJSDev.test('PRODUCTION')) {
   pdfjsWebApp = require('./app.js');
+  pdfjsWebAppOptions = require('./app_options.js');
 }
 
 if (typeof PDFJSDev !== 'undefined' && PDFJSDev.test('FIREFOX || MOZCENTRAL')) {
@@ -180,14 +181,17 @@ function webViewerLoad() {
   if (typeof PDFJSDev === 'undefined' || !PDFJSDev.test('PRODUCTION')) {
     Promise.all([
       SystemJS.import('pdfjs-web/app'),
+      SystemJS.import('pdfjs-web/app_options'),
       SystemJS.import('pdfjs-web/genericcom'),
       SystemJS.import('pdfjs-web/pdf_print_service'),
-    ]).then(function([app, ...otherModules]) {
+    ]).then(function([app, appOptions, ...otherModules]) {
       window.PDFViewerApplication = app.PDFViewerApplication;
+      window.PDFViewerApplicationOptions = appOptions.AppOptions;
       app.PDFViewerApplication.run(config);
     });
   } else {
     window.PDFViewerApplication = pdfjsWebApp.PDFViewerApplication;
+    window.PDFViewerApplicationOptions = pdfjsWebAppOptions.AppOptions;
     pdfjsWebApp.PDFViewerApplication.run(config);
   }
 }