# [Android Components](../../README.md) > Samples > Firefox Accounts (FxA)

![](src/main/res/mipmap-xhdpi/ic_launcher.png)

A simple app showcasing the service-firefox-account component.

## Concepts

The main concepts shown in the sample app are:

* Usage of the asynchronous result type `Deferred`
* Setting up a`FirefoxAccount` object, from a previous session or from scratch
* Spawning a custom tab or a WebView to handle the user's authentication flow

A minimal walkthrough is also provided in the [component README](https://github.com/mozilla-mobile/android-components/tree/master/components/service/firefox-accounts).

## Setting up the account

### From a previous session

`FirefoxAccount` is a representation of the authentication state for the current client. It provides two methods for saving and restoring state: `toJSONString` and `fromJSONString`.

> The state provided by `toJSONString` should be stored securely, as the credentials inside could in theory let a user stay authenticated forever.

To restore an account from an existing state in shared preferences:

```kotlin
// Inside a `launch` or `async` block:
getSharedPreferences(FXA_STATE_PREFS_KEY, Context.MODE_PRIVATE).getString(FXA_STATE_KEY, "").let {
	FirefoxAccount.fromJSONString(it)
}
```

To persist an account's state in shared preferences:

```kotlin
account.toJSONString().let {
    getSharedPreferences(FXA_STATE_PREFS_KEY, Context.MODE_PRIVATE).edit().putString(FXA_STATE_KEY, it).apply()
}
```

### From scratch

If no previous auth state was found, we have to create a new one using some default OAuth parameters. Find the hostname, or `CONFIG_URL` for your OAuth provider, then create a `CLIENT_ID` and `REDIRECT_URL` for your application. From there, we can create a `Config` object, and finally our `FirefoxAccount` object:

```kotlin
val config = Config(CONFIG_URL, CLIENT_ID, REDIRECT_URL)
// Some helpers such as Config.release(CLIENT_ID, REDIRECT_URL)
// are also provided for well-known Firefox Accounts servers.
val account = FirefoxAccount(config)
```

## Viewing the web pages

In order to complete the OAuth flow, the app can spawn a view and capture the code/state parameters in one of three ways:

* Opening a custom tab, then capturing params via intent filters
* Spawning a WebView with a page load hook
* Spawning an EngineView (WebView/GeckoView) [WIP]

## License

    This Source Code Form is subject to the terms of the Mozilla Public
    License, v. 2.0. If a copy of the MPL was not distributed with this
    file, You can obtain one at http://mozilla.org/MPL/2.0/
