# Sign In with Email/Phone Number

> **Concepts:** Learn about how [**Sign in with Email/Phone Number**](/features/verify-email-phone.md) works.

### Overview

Verifying **email and phone number** in your mobile app using our React Native SDK consists of the following steps:

1. Call Cotter's Login function
2. Setup deep linking
3. Receive user's email or phone number, and whether or not it's verified

### What you're building

![Cotter's React Native SDK on Android and iOS](/files/-M1dlHYUGE23fmcVeogG)

## Steps

1. [Import Cotter as a dependency](/sdk-reference/react-native/react-native-sdk-verify-email-phone.md#step-1-import-cotter-as-a-dependency)
2. [Sign Up or Login with Email or Phone](/sdk-reference/react-native/react-native-sdk-verify-email-phone.md#step-2-signing-up-or-logging-in)
3. [Setup deep linking](/sdk-reference/react-native/react-native-sdk-verify-email-phone.md#step-3-setup-deep-linking): Cotter's authentication will redirect back to your application using a URL scheme.
4. [Receive the Token](/sdk-reference/react-native/react-native-sdk-verify-email-phone.md#step-4-receiving-the-token-in-onsuccess-or-onerror): Include the returned OAuth token and email/phone number in your server

### Step 1: Import Cotter as a dependency

{% hint style="info" %}
Make sure you're using `react-native` version **< 0.63**
{% endhint %}

{% tabs %}
{% tab title="yarn" %}

```java
yarn add react-native-cotter react-native-device-info rn-secure-storage react-native-randombytes react-native-camera react-native-svg react-native-securerandom buffer react-native-inappbrowser-reborn react-native-sha256
npx pod-install ios
```

{% endtab %}

{% tab title="npm" %}

```
npm install --save react-native-cotter react-native-device-info rn-secure-storage react-native-randombytes react-native-camera react-native-svg react-native-securerandom buffer react-native-inappbrowser-reborn react-native-sha256
npx pod-install ios
```

{% endtab %}
{% endtabs %}

*(Optional) Checkout additional steps* [*for Android, React Native < 0.60, and Manual Installation*](/sdk-reference/react-native/installation.md)*.*&#x20;

### Step 2: Signing Up or Logging In

#### Sign Up: Use the sign up method to:

* Verify the user's email or phone number
* Then create a new user in Cotter if successful
* **If you passed-in the email/phone into the function**: if your user already exists, **it will return an error "User already exists"**
* **If you does not pass in the email/phone into the function:** users can enter their email/phone in the pop-up browser, but it will NOT check if the user already exists. It will behave like the Log In method below.

> **Tip:** Use the "Sign Up" method and pass in the user's email/phone to differentiate new and existing user. You can have an input text and collect the user's email/phone.

#### Log In: Use the login method to:

* To authenticate a user based on their email.
* If the user doesn't exist, this method **will automatically create a new user.**

> **Tip:** Use the "Log In" method to login or register user on the same page

{% tabs %}
{% tab title="Using Email" %}

```javascript
import { Cotter } from 'react-native-cotter';

let cotter = new Cotter(API_KEY_ID);   // your API_KEY_ID
await cotter.signUpWithEmailLink(      // use Email & Magic Link
  'myexample://auth_callback',         // (setup later) URL Scheme for deep linking
  (resp) => {console.log(resp)},       // Success Callback Function
  (err) => {console.log(err)}, // Error Callback Function
  {email: this.state.email},           // (Optional) , if you leave this blank, user can enter email in the in-app browser
);
```

#### Sign Up

* **Magic Link:** use `cotter.signUpWithEmailLink`
* **OTP:** use `cotter.signUpWithEmailOTP`

#### Sign In

* **Magic Link:** use `cotter.signInWithEmailLink`
* **OTP:** use `cotter.signInWithEmailOTP`

**If no email is specified**, the user can enter the email in the in-app browser
{% endtab %}

{% tab title="Using Phone" %}

```javascript
import { Cotter } from 'react-native-cotter';

let cotter = new Cotter(API_KEY_ID);            // your API_KEY_ID
await cotter.signUpWithPhoneLink(               // use Phone & Magic Link
  'myexample://auth_callback',                  // (setup later) URL Scheme for deep linking
  (resp) => {console.log(resp)},                // Success Callback Function
  (err) => {console.log(err)},          // Error Callback Function
  {phone: this.state.phone, channel: "SMS" },   // (Optional), if you leave this blank, user can enter email in the in-app browser
);
```

#### **Sign Up**

* **Magic Link:** use `cotter.signUpWithPhoneLink`
* **OTP:** use `cotter.signUpWithPhoneOTP`

#### **Sign In**

* **Magic Link:** use `cotter.signInWithPhoneLink`
* **OTP:** use `cotter.signInWithPhoneOTP`

#### Channels: (default to "SMS" if phone is specified)

* To use SMS: `{phone: this.state.phone, channel: "SMS"}`
* To use WhatsApp: `{phone: this.state.phone, channel: "WHATSAPP"}`

**If no phone number is specified**, the user can enter the phone number in the in-app browser and there will be buttons for WhatsApp and SMS available (based on your settings in the Dashboard > Branding).

{% hint style="info" %}
To send code/link via SMS or WhatsApp, you'll need to add some balance to you project in the [Dashboard](https://dev.cotter.app/).
{% endhint %}
{% endtab %}
{% endtabs %}

{% hint style="success" %}
**Try this now!** You should see an in-app browser looking like the image below popping up and ask you to authenticate.
{% endhint %}

![](/files/-M1doM-5Nwjmc8sO7YxE)

### Step 3: Setup Deep Linking

Pick a unique URL scheme for redirecting the user back to your app after the verification in the in-app browser is successful. For this example, we'll use `myexample://auth_callback` .

{% hint style="warning" %}
Make sure your URL scheme (the front part before `://`) doesn't have an underscore or other special characters. To test it out, enter your Redirect URL here: <https://jsfiddle.net/omd02jn5/>
{% endhint %}

### Setup in Android

Add this in your [android/app/src/main/**AndroidManifest.xml**](https://github.com/cotterapp/react-native-cotter/blob/9bc206e3b5c815a5ded65627e8bb172db293f83d/examples/android/app/src/main/AndroidManifest.xml#L23)

```markup
<activity
    android:name=".MainActivity"
    android:launchMode="singleTask"> <!-- Make launchMode to singleTask --> 
    
    <intent-filter>
        <action android:name="android.intent.action.MAIN" />
        <category android:name="android.intent.category.LAUNCHER" />
    </intent-filter>

    <!--    Setup Deep Linking Here    -->
    <intent-filter>
        <action android:name="android.intent.action.VIEW" />
        <category android:name="android.intent.category.DEFAULT" />
        <category android:name="android.intent.category.BROWSABLE" />
        <!-- This is for myexample://auth_callback -->
        <!-- 👇 Change this to your own URL scheme -->
        <data android:scheme="myexample" android:host="auth_callback"/>
    </intent-filter>
    <!--  end -->
    
</activity>
```

### Setup in iOS

Add this in your [ios/\<YourAppName>/Info.plist](https://github.com/cotterapp/react-native-cotter/blob/master/examples/ios/examples/Info.plist#L26)

```markup
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>

	<!-- ADD THE LINES FROM HERE -->
	<key>CFBundleURLTypes</key>
	<array>
		<dict>
			<key>CFBundleTypeRole</key>
			<string>Editor</string>
			<key>CFBundleURLName</key>
			<string>myexample</string> <!-- 👈 Change this to your own URL Scheme -->
			<key>CFBundleURLSchemes</key>
			<array>
				<string>myexample</string> <!-- 👈 Change this to your own URL Scheme -->
			</array>
		</dict>
	</array>
	<!-- TO HERE -->

	<key>CFBundleDevelopmentRegion</key>
	<string>en</string>
```

If you're targeting iOS 9.x or newer, add the following lines to [YourApp/ios/YourApp/AppDelegate.m](https://github.com/proyecto26/react-native-inappbrowser/blob/master/example/ios/example/AppDelegate.m):

{% tabs %}
{% tab title="iOS 9.x or newer" %}

```swift
// Add the header at the top of the file:
#import <React/RCTLinkingManager.h>

// Add this above `@end`:
- (BOOL)application:(UIApplication *)application
   openURL:(NSURL *)url
   options:(NSDictionary<UIApplicationOpenURLOptionsKey,id> *)options
{
  return [RCTLinkingManager application:application openURL:url options:options];
}
```

{% endtab %}
{% endtabs %}

If you're targeting iOS 8.x or older, you can use the following code instead, add the following lines to [YourApp/ios/YourApp/AppDelegate.m](https://github.com/proyecto26/react-native-inappbrowser/blob/master/example/ios/example/AppDelegate.m):

```swift
// Add the header at the top of the file:
#import <React/RCTLinkingManager.h>

// Add this above `@end`:
- (BOOL)application:(UIApplication *)application openURL:(NSURL *)url
  sourceApplication:(NSString *)sourceApplication annotation:(id)annotation
{
  return [RCTLinkingManager application:application openURL:url
                      sourceApplication:sourceApplication annotation:annotation];
}
```

If your app is using Universal Links, you'll need to add the following code as well, add the following lines to [YourApp/ios/YourApp/AppDelegate.m](https://github.com/proyecto26/react-native-inappbrowser/blob/master/example/ios/example/AppDelegate.m):

```swift
// Add this above `@end`:
- (BOOL)application:(UIApplication *)application continueUserActivity:(nonnull NSUserActivity *)userActivity
 restorationHandler:(nonnull void (^)(NSArray<id<UIUserActivityRestoring>> * _Nullable))restorationHandler
{
 return [RCTLinkingManager application:application
                  continueUserActivity:userActivity
                    restorationHandler:restorationHandler];
}
```

### Setup in React Native Project

{% tabs %}
{% tab title="React Navigation" %}
In your App.js

```javascript
import { createStackNavigator } from 'react-navigation'

// Import Cotter's Loading Page
import { LoadingPage } from 'react-native-cotter';
 
const Main = createStackNavigator(
  {
    ...
    Register: { screen: Register },
    
    // Redirect users Cotter's Handler page
    CotterLoadingVerify: { 
      screen: LoadingPage, // Use Cotter's Loading Page
      path: 'auth_callback' // Enable Deep linking redirection
    },
    
  }
)
```

If you have Nested Stack Navigator, add `path: ''` to every parent stack.

```javascript
// TARGET STACK
const RegisterStack = createStackNavigator(
  {
    Register: { screen: Register },
    CotterLoadingVerify: {
      screen: LoadingPage, // Use Cotter's Loading Page
      path: 'auth_callback', // Enable Deep linking redirection
    },
  }
);

// PARENT 1
const RootStack = createStackNavigator(
  {
    // ADD path: '' here
    RegisterStack: { screen: RegisterStack, path: '' },
    ...
  }
);

// PARENT of PARENT 1
const RootSwitch = createSwitchNavigator(
  {
    Splash: { screen: Splash },
    // ADD path: '' here
    RootStack: { screen: RootStack, path: '' },
  }
);
```

{% endtab %}

{% tab title="React Navigation 5 or above" %}
If you're using the [newer version of React Navigation](https://reactnavigation.org/docs/deep-linking#deep-link-integration), copy paste the code below to your App.js or index.js.

**In your App.js or index.js**

```javascript
import { NavigationContainer, useLinking } from '@react-navigation/native';

function App() {
  const ref = React.useRef();

  const {getInitialState} = useLinking(ref, {
    prefixes: ['https://myexample.cotter.app', 'myexample://'],
    config: {
      CotterLoadingVerify: 'auth_callback', // ADD THIS TO REDIRECT TO COTTER'S HANDLER PAGE
    },
  });

  const [isReady, setIsReady] = React.useState(false);
  const [initialState, setInitialState] = React.useState();

  React.useEffect(() => {
    Promise.race([
      getInitialState(),
      new Promise(resolve =>
        // Timeout in 150ms if `getInitialState` doesn't resolve
        // Workaround for https://github.com/facebook/react-native/issues/25675
        setTimeout(resolve, 150)
      ),
    ])
      .catch(e => {
        console.error(e);
      })
      .then(state => {
        if (state !== undefined) {
          setInitialState(state);
        }

        setIsReady(true);
      });
  }, [getInitialState]);

  if (!isReady) {
    return null;
  }

  return (
    <NavigationContainer initialState={initialState} ref={ref}>
      {/* content 👈 */}
    </NavigationContainer>
  );
}
```

**In your Router**

```javascript
import {LoadingPage} from 'react-native-cotter';

function Router() {
  return (
    <Stack.Navigator>
      ...
      
      // Add CotterLoadingVerify page
      <Stack.Screen
        name="CotterLoadingVerify"
        component={LoadingPage}
        options={{headerShown: false}}
      />
      
    </Stack.Navigator>
  );
}
```

{% endtab %}
{% endtabs %}

{% hint style="info" %}
Remember to make sure your [callbackURL in Step 2 ](/sdk-reference/react-native/react-native-sdk-verify-email-phone.md#step-2-call-cotters-verify-function)is correct.
{% endhint %}

{% hint style="success" %}
**Try it again!** You should see the in-app browser redirecting back after you've successfully verified.
{% endhint %}

### Step 4: Receiving the Token in onSuccess or onError

#### onError

The `onError` function that you pass in will receive 2 parameters: `errorMessage` (string) and `errorResponse` (object). The `errorResponse` is an http response from attempt to verify the user's email/phone in Cotter's server.

#### onSuccess

The `onSuccess` function that you pass in will receive a `response` object that looks like this:

```javascript
{
  "identifier": {
    "ID": "f4286df9-a923-429c-bc33-5089ffed5f68",
    "created_at": "2020-07-21T22:53:21.211367Z",
    "updated_at": "2020-07-21T22:53:21.211367Z",
    "deleted_at": "0001-01-01T00:00:00Z",
    "identifier": "putri@cotter.app", // User's email
    "identifier_type": "EMAIL",
    "device_type": "BROWSER",
    "device_name": "Mozilla/5.0 (Linux; Android 9; Android SDK built for x86 Build/PSR1.180720.075) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/69.0.3497.100 Mobile Safari/537.36",
    "expiry": "2020-08-20T22:53:21.19705Z",
    "timestamp": "2020-07-21T22:53:21.19705Z"
  },
  "oauth_token": {
    "access_token": "eyJhbGciOiJFUz...", // Validate this access token
    "id_token": "eyJhbGciOiJFUzI1...",
    "refresh_token": "27944:lb31DY5pG229n...",
    "expires_in": 3600,
    "token_type": "Bearer",
    "auth_method": "OTP"
  },
  "token": {...},
  "user": {
    "ID": "643a42c7-316a-4abe-b27e-f4d0f903bfea", // [Deprecated] Cotter uesr ID
    "identifier": "putri@cotter.app",
    ...
  }
}
```

{% hint style="warning" %}
Please use the identifier (email/phone number) as your main way to identify users, **user.ID is deprecated.**
{% endhint %}

This JSON object contains 3 objects, `identifier` , `oauth_token` and `user` .&#x20;

* The identifier object contains information about the user's email or phone number, device type and name, and expiry.
* The `oauth_token` contains an `access_token` that you can validate in your backend.
* The `user` contains the User object in Cotter, which includes a "Cotter User ID". **You should associate your user with this Cotter User ID for reference.**

{% hint style="success" %}
You should include this JSON Object into your call to your backend for **Login** or **Registration**. Your backend should then verify that [the access token is valid.](/getting-access-token/verifying-jwt-tokens.md)
{% endhint %}

## Validating Cotter's Access Token&#x20;

Checkout how to verify the OAuth Tokens from Cotter here:

{% content-ref url="/pages/-M4HZPVawEx2QN3qLmnv" %}
[Verifying JWT Tokens](/getting-access-token/verifying-jwt-tokens.md)
{% endcontent-ref %}

## 🎉 You're done!

## Securing your Project

Since you'll be using your API Key from a front-end website or mobile app, your `API_KEY_ID` is exposed to anyone inspecting your code. Here are some ways to prevent abuse:

* [Only allow your website/app to use your API Key](/protecting-your-account/only-allow-your-website-app-to-use-your-api-key.md)
* [Rate Limit the number of authentication requests](/protecting-your-account/rate-limit.md)
* [Enable reCAPTCHA to prevent automated abuse](/protecting-your-account/enable-recaptcha-to-protect-against-automated-abuse.md)


---

# 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/sdk-reference/react-native/react-native-sdk-verify-email-phone.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.