Storage

UnoFeatures: Storage (add to <UnoFeatures> in your .csproj)

Uno.Extensions.Storage facilitate local data storage across multiple platforms, including WebAssembly, Android, iOS, macOS, Desktop and Windows. This extension is particularly useful for applications that require secure, persistent storage of user preferences, configuration settings, and sensitive information such as tokens and credentials.

Important

On Apple platforms (iOS, Mac Catalyst) the Uno storage extension, used by the authentication extension, uses the OS Key Chain service to store secrets. This requires your application to have the proper entitlements to work properly.

Installation

Storage is provided as an Uno Feature. To enable Storage support in your application, add Storage to the <UnoFeatures> property in the Class Library (.csproj) file.

<UnoFeatures>
    Material;
    Extensions;
+   Storage;
    Toolkit;
    MVUX;
</UnoFeatures>

Important

If your project doesn't have any of the Uno.Extension features set up yet, check out our Installing Extensions in an existing project docs to ensure you have all the necessary setup details.

Important

This walkthrough assumes you created your app using the Single Project template. If you used a different template, please refer to our Migrating Projects to Single Project documentation.

For more information about UnoFeatures refer to our Using the Uno.Sdk docs.

Key-value storage

UseStorage() registers a default IKeyValueStorage per platform. Everything built on top of it — most visibly the authentication token cache — writes through this default:

Platform	Default store
Windows (WinAppSDK)	ApplicationData settings, DPAPI-encrypted
Android (native renderer)	KeyStore
iOS (native renderer)	Keychain
Android / iOS with the Skia renderer	ApplicationData settings (unencrypted, inside the app sandbox) — see the note below
WebAssembly	Browser storage — localStorage by default, see below
Other (e.g. Skia Desktop)	ApplicationData settings (unencrypted file)

Note

On Android and iOS heads built with UnoFeatures=SkiaRenderer, the Uno SDK loads this package's plain netX.0 build rather than its netX.0-android / netX.0-ios one (the same substitution it applies to every Uno.UI-referencing package), and the KeyStore / Keychain stores only exist in the platform builds. The default there is therefore ApplicationData, which the OS sandboxes per app but does not encrypt. Register your own IKeyValueStorage as the default if you need more than the sandbox on those heads.

WebAssembly: choosing the browser store

The browser has no protected store, so on WebAssembly the choice is about lifetime, not encryption. Configure it in the storage section:

{
  "KeyValueStorageConfiguration": {
    "BrowserCacheLocation": "LocalStorage"
  }
}

Value	Behavior
LocalStorage (default)	Survives a page reload, closing the tab, and restarting the browser. This is what WebAssembly used before the setting existed, so upgrading never relocates an app's existing data.
SessionStorage	Survives a page reload; cleared when the tab closes. The tightest persistent lifetime — worth opting into for anything holding credentials.
MemoryStorage	Nothing is written to browser storage; values live for the lifetime of the page only.

An invalid value throws while the host is being built rather than silently falling back — deliberate for a setting that decides where credentials live. Numeric values are rejected too. The setting is ignored on every other platform.

Because this selects the single host-wide default store, it also governs the authentication token cache — whatever the authentication provider is, and whatever name it was registered under. For the security implications when tokens are involved (MSAL, refresh-token lifetime, the Entra spa registration), see MSAL Authentication.