diff --git a/packages/global-scope/README.md b/packages/global-scope/README.md
index adcd4d26..285c3048 100644
--- a/packages/global-scope/README.md
+++ b/packages/global-scope/README.md
@@ -10,6 +10,10 @@ yarn add @alwatr/global-scope
 
 ## Usage
 
+### globalScope
+
+Alternative to `globalThis` that works cross-platform.
+
 ```typescript
 import {globalScope} from '@alwatr/global-scope';
 
@@ -22,3 +26,19 @@ globalScope.setTimeout(() => {
   console.log(globalScope.alwatr.version); // 1.0.0
 }, 1_000);
 ```
+
+### sharedScope_
+
+A global variable that can be used to share state across modules without accessible publicly in the global scope.
+
+```typescript
+// module1.ts
+import {sharedScope_} from '@alwatr/global-scope';
+sharedScope_.foo = 'bar';
+```
+
+```typescript
+// module2.ts
+import {sharedScope_} from '@alwatr/global-scope';
+console.log(sharedScope_.foo); // 'bar'
+```
diff --git a/packages/global-scope/package.json b/packages/global-scope/package.json
index f092a76b..337dfc37 100644
--- a/packages/global-scope/package.json
+++ b/packages/global-scope/package.json
@@ -72,6 +72,7 @@
     "@alwatr/nano-build": "workspace:^",
     "@alwatr/prettier-config": "workspace:^",
     "@alwatr/tsconfig-base": "workspace:^",
+    "@types/node": "^20.10.5",
     "typescript": "^5.3.3"
   }
 }
diff --git a/packages/global-scope/src/main.ts b/packages/global-scope/src/main.ts
index 69121cb9..e8c74e50 100644
--- a/packages/global-scope/src/main.ts
+++ b/packages/global-scope/src/main.ts
@@ -1,8 +1,40 @@
 /**
  * Alternative to `globalThis` that works cross-platform.
+ *
+ * @example
+ * ```typescript
+ * globalScope.alwatr = {
+ *  ...globalScope.alwatr,
+ *  foo: 'bar',
+ * }
+ * ```
  */
-export const globalScope =
+export const globalScope: typeof globalThis =
   (typeof globalThis === 'object' && globalThis) ||
-  ('object' === typeof window && window) ||
-  ('object' === typeof global && global) ||
+  (typeof window === 'object' && window) ||
+  (typeof global === 'object' && global) ||
   self;
+
+/**
+ * A global variable that can be used to share state across modules without accessible publicly in the global scope.
+ *
+ * @example
+ * ```typescript
+ * // module1.ts
+ * shareScope_.foo = 'bar';
+ *
+ * // module2.ts
+ * console.log(shareScope_.foo); // 'bar'
+ * ```
+ */
+export const sharedScope_: Record<string, unknown> = {};
+
+declare global {
+  // eslint-disable-next-line no-var
+  var __shared_scope_defined__: boolean;
+}
+
+if (globalScope.__shared_scope_defined__ !== undefined) {
+  throw new Error('global_scope_module_duplicated');
+}
+globalScope.__shared_scope_defined__ = true;
diff --git a/packages/global-scope/src/platform.ts b/packages/global-scope/src/platform.ts
new file mode 100644
index 00000000..e69de29b
diff --git a/yarn.lock b/yarn.lock
index 716b2d54..b966da95 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -63,6 +63,7 @@ __metadata:
     "@alwatr/nano-build": "workspace:^"
     "@alwatr/prettier-config": "workspace:^"
     "@alwatr/tsconfig-base": "workspace:^"
+    "@types/node": "npm:^20.10.5"
     typescript: "npm:^5.3.3"
   languageName: unknown
   linkType: soft
@@ -1058,6 +1059,15 @@ __metadata:
   languageName: node
   linkType: hard
 
+"@types/node@npm:^20.10.5":
+  version: 20.10.5
+  resolution: "@types/node@npm:20.10.5"
+  dependencies:
+    undici-types: "npm:~5.26.4"
+  checksum: be30609aae0bfe492097815f166ccc07f465220cb604647fa4e5ec05a1d16c012a41b82b5f11ecfe2485cbb479d4d20384b95b809ca0bcff6d94d5bbafa645bb
+  languageName: node
+  linkType: hard
+
 "@types/normalize-package-data@npm:^2.4.1":
   version: 2.4.3
   resolution: "@types/normalize-package-data@npm:2.4.3"
@@ -5694,6 +5704,13 @@ __metadata:
   languageName: node
   linkType: hard
 
+"undici-types@npm:~5.26.4":
+  version: 5.26.5
+  resolution: "undici-types@npm:5.26.5"
+  checksum: bb673d7876c2d411b6eb6c560e0c571eef4a01c1c19925175d16e3a30c4c428181fb8d7ae802a261f283e4166a0ac435e2f505743aa9e45d893f9a3df017b501
+  languageName: node
+  linkType: hard
+
 "unicorn-magic@npm:^0.1.0":
   version: 0.1.0
   resolution: "unicorn-magic@npm:0.1.0"