react-native-shared-container

shared session storage for React Native.

Share a small key/value store (auth tokens, user id, feature flags, …) between multiple apps published by the same team / signed with the same key, plus a per-app private store.

| Platform | shared scope backed by | local scope backed by | | -------- | ------------------------ | ----------------------- | | iOS | App Group container (NSUserDefaults suite) | NSUserDefaults.standard | | Android | Exported, signature-protected ContentProvider | private SharedPreferences |

Only apps signed with the same key (Android) or sharing the same App Group (iOS) can read each other's shared data, so the store is safe from third-party apps.

Installation

npm install react-native-shared-container
# or
yarn add react-native-shared-container

iOS

cd ios && pod install

Then, for every app that should share data:

1. Add the App Groups capability and enable the same group id in each app target (e.g. group.com.technoidentity.shared.container).
2. Either add that id as SharedAppGroupID in each app's Info.plist, or pass it at runtime via configure({ appGroupId }).

Android

Autolinking registers the module and its ContentProvider. The provider authority and the signature-level permission are scoped to each app's applicationId automatically — no manifest edits are needed in the common case. All participating apps must be signed with the same key.

Usage

import {
  configure,
  getItem,
  setItem,
  removeItem,
  appId,
  type Scope,
} from 'react-native-shared-container';

// Call once at app start-up, before reading/writing the `shared` scope.
await configure({
  // Android: the OTHER apps that share the session (your own id is added automatically).
  peerAppIds: ['com.technoidentity.shared.container', 'com.technoidentity.shared.container.two'],
  // iOS: the App Group container (optional if set via SharedAppGroupID in Info.plist).
  appGroupId: 'group.com.technoidentity.shared.container',
});

// Cross-app, shared between all signed-together apps:
await setItem('shared', 'authToken', 'abc123');
const token = await getItem('shared', 'authToken'); // -> 'abc123' in every sibling app

// Per-app private:
await setItem('local', 'lastTab', 'home');

await removeItem('shared', 'authToken');

console.log('Running inside app:', appId);

API

configure(config?): Promise<boolean>

| Field | Platform | Description | | ------------ | -------- | ----------- | | peerAppIds | Android | applicationIds of the sibling apps that share the session. Your own id is always included. | | appGroupId | iOS | App Group container id for the shared scope. Falls back to SharedAppGroupID in Info.plist. |

getItem(scope, key): Promise<string | null>

setItem(scope, key, value): Promise<boolean>

removeItem(scope, key): Promise<boolean>

scope is 'local' (per-app private) or 'shared' (cross-app).

appId: string

The applicationId / bundle identifier of the running app.

How it works

• iOS — the shared scope opens an NSUserDefaults suite for the configured App Group. Every app target that declares the same group reads and writes the same container.
• Android — each app exposes an exported ContentProvider at content://<applicationId>.sharedsession, locked behind a signature-level permission. On write, the value is fanned out to every configured peer's provider; on read, peers are queried in turn. Apps that aren't installed are skipped safely.

Example

A runnable two-app demo (App A / App B) lives in example/.

License

MIT