# 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  →](https://docs.cotter.app/features/verify-email-phone)

* [HTML Quickstart](https://docs.cotter.app/quickstart-guides/html-magic-link-with-email-and-phone)
* [React Quickstart](https://docs.cotter.app/quickstart-guides/react-magic-link-with-email-and-phone)
* [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  →](https://docs.cotter.app/features/passwordless-login)

* [React Native Quickstart](https://docs.cotter.app/quickstart-guides/react-native-quickstart)
* [Flutter Quickstart](https://docs.cotter.app/quickstart-guides/flutter-sign-in-with-device)
* [iOS Quickstart](https://docs.cotter.app/quickstart-guides/ios-quickstart)

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

* [React Quickstart](https://docs.cotter.app/quickstart-guides/react-webauthn)

## 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](https://docs.cotter.app/sdk-reference/web)
* [React Native](https://docs.cotter.app/sdk-reference/react-native)
* [Flutter](https://docs.cotter.app/sdk-reference/flutter)
* [iOS](https://docs.cotter.app/sdk-reference/ios)
* [Android](https://docs.cotter.app/sdk-reference/android)
* [Other Mobile App Frameworks](https://docs.cotter.app/sdk-reference/api-for-other-mobile-apps)
* [Backend: Handling Response](https://docs.cotter.app/sdk-reference/backend-handling-response) 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="getting-access-token" %}
[getting-access-token](https://docs.cotter.app/getting-access-token)
{% 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)


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://docs.cotter.app/master.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.