> ## Documentation Index
> Fetch the complete documentation index at: https://docs.turnkey.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Overview

> Learn how to set up, log in, or sign up easily in your Android app using the Turnkey Kotlin SDK.

The Kotlin SDK makes authentication simple.
You can call specific login and signup functions to create your own UI components and authentication flow.

## Authentication state

To check if a user is authenticated, you can use the `authState` variable from the `TurnkeyContext`.

```kotlin theme={"system"}
val authState: AuthState = TurnkeyContext.authState.value
```

## Customize sub-organization creation

Need to configure default user names, passkey names, wallet creations or anything sub-org related?
You can learn more about customizing the sub-orgs you create in the [Sub-Organization Customization](/sdks/kotlin/sub-organization-customization) section.

Follow the guides below to learn how to set up email and SMS authentication, passkey authentication, and social logins in your Android app.

<CardGroup>
  <Card title="Email & SMS" href="/sdks/kotlin/authentication/email-sms" icon="file-lines" iconType="solid" horizontal>
    Learn how to set up email and SMS authentication in your Android app.
  </Card>

  <Card title="Passkey Authentication" href="/sdks/kotlin/authentication/passkey" icon="file-lines" iconType="solid" horizontal>
    Learn how to set up passkey authentication in your Android app.
  </Card>

  <Card title="Social Logins" href="/sdks/kotlin/authentication/social-logins" icon="file-lines" iconType="solid" horizontal>
    Discover how to create and manage social logins in your Kotlin
    application, including wallet creation, account derivation, and more.
  </Card>

  <Card title="Relying party ID (rpId) setup" href="/sdks/kotlin/authentication/rp-id-setup" icon="file-lines" iconType="solid" horizontal>
    Learn how to set up the relying party ID (rpId) for passkey authentication in your Android app.
  </Card>
</CardGroup>