> For the complete documentation index, see [llms.txt](https://docs.cotter.app/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.cotter.app/master.md).

# Getting Started

## Get Started

Cotter allows you to build a login system in just a few minutes. **There are 3 main methods of logging-in.** You can either choose 1 or combine the methods. 

Quickly get started with **our 5-minutes tutorials**:

💬 **Sign in with email/phone number:** Authenticate using a Magic Link or Verification Code. [Learn More  →](/features/verify-email-phone.md)

* [HTML Quickstart](/quickstart-guides/html-magic-link-with-email-and-phone.md)
* [React Quickstart](/quickstart-guides/react-magic-link-with-email-and-phone.md)
* [Next.js Tutorial](https://blog.cotter.app/passwordless-login-with-email-and-json-web-token-jwt-authentication-with-nextjs/)
* [Angular Tutorial](https://blog.cotter.app/angular-send-email-sms-and-whatsapp-verification-code-for-new-users-worldwide/)
* [Webflow Tutorial](https://blog.cotter.app/integrate-cotter-magic-link-to-webflow-in-less-than-15-minutes/)

🔐 **Sign In with Device on Mobile Apps:** Authenticate users based on the ownership of a device. [Learn More  →](/features/passwordless-login.md)

* [React Native Quickstart](/quickstart-guides/react-native-quickstart.md)
* [Flutter Quickstart](/quickstart-guides/flutter-sign-in-with-device.md)
* [iOS Quickstart](/quickstart-guides/ios-quickstart.md)

🧬 **Sign in with WebAuthn:** Authenticate users using TouchID/Windows Hello from your website. [Learn More  →](/features/sign-in-with-webauthn.md)

* [React Quickstart](/quickstart-guides/react-webauthn.md)

## Customization

Customize Cotter's Login Form from the [Dashboard > Branding](https://dev.cotter.app/). Currently this works for the Web SDKs for Sign in with Email/Phone using a Magic Link and OTP.

## Dig Deeper

Follow the full SDK reference for a fully customizable login flow and get OAuth 2.0 support for your API endpoints.

* [Web](/sdk-reference/web.md)
* [React Native](/sdk-reference/react-native.md)
* [Flutter](/sdk-reference/flutter.md)
* [iOS](/sdk-reference/ios.md)
* [Android](/sdk-reference/android.md)
* [Other Mobile App Frameworks](/sdk-reference/api-for-other-mobile-apps.md)
* [Backend: Handling Response](/sdk-reference/backend-handling-response.md) that you receive when a user authenticates

## OAuth 2.0: Get Access Token from Cotter

Cotter can generate OAuth Tokens (access token, id token, and refresh token) to be used for your APIs. This functionality is available from Cotter's SDK.

{% content-ref url="/pages/-M4HUyscnpVWv0mVDRba" %}
[🗝️ Getting Access Token](/getting-access-token/handling-authentication-with-cotter.md)
{% endcontent-ref %}

## Example Apps

[HTML Example](https://codesandbox.io/s/client-side-working-example-hiy8w?file=/index.html)

[ReactNative Example App](https://github.com/cotterapp/react-native-sdk/tree/master/examples)

[Flutter Example App](https://github.com/cotterapp/flutter-sdk/tree/master/example)

[Android Example App](https://github.com/cotterapp/android-example)

[Biometric and PIN iOS Example](https://github.com/cotterapp/ios-sdk)