Authenticate with Firebase using Password-Based Accounts on iOS

You can use Firebase Authentication to let your users authenticate with Firebase using their email addresses and passwords, and to manage your app's password-based accounts.

Before you begin

Add Firebase to your iOS project. Include the following pods in your Podfile:
```
pod 'Firebase/Auth'
```
If you haven't yet connected your app to your Firebase project, do so from the Firebase console.
Enable Email/Password sign-in:
1. In the Firebase console, open the Auth section.
2. On the Sign in method tab, enable the Email/password sign-in method and click Save.

Create a password-based account

To create a new user account with a password, complete the following steps in your app's sign-in activity:

Import the Firebase module in your UIApplicationDelegate:
Swift
```
import Firebase
```
Objective-C
```
@import Firebase;
```
Configure a FirebaseApp shared instance, typically in your app's application:didFinishLaunchingWithOptions: method:
Swift
```
// Use Firebase library to configure APIs
FirebaseApp.configure()
```
Objective-C
```
// Use Firebase library to configure APIs
[FIRApp configure];
```
When a new user signs up using your app's sign-up form, complete any new account validation steps that your app requires, such as verifying that the new account's password was correctly typed and meets your complexity requirements.

Create a new account by passing the new user's email address and password to createUserWithEmail:email:password:completion:.

Swift

Auth.auth().createUser(withEmail: email, password: password) { authResult, error in
  // ...
}

Objective-C

[[FIRAuth auth] createUserWithEmail:email
                           password:password
                         completion:^(FIRAuthDataResult * _Nullable authResult,
                                      NSError * _Nullable error) {
  // ...
}];

If the new account was successfully created, the user is signed in, and you can get the user's account data from the result object that's passed to the callback method.

Sign in a user with an email address and password

The steps for signing in a user with a password are similar to the steps for creating a new account. In your app's sign-in activity, do the following:

Import the Firebase module in your UIApplicationDelegate:
Swift
```
import Firebase
```
Objective-C
```
@import Firebase;
```
Configure a FirebaseApp shared instance, typically in your app's application:didFinishLaunchingWithOptions: method:
Swift
```
// Use Firebase library to configure APIs
FirebaseApp.configure()
```
Objective-C
```
// Use Firebase library to configure APIs
[FIRApp configure];
```

When a user signs in to your app, pass the user's email address and password to signInWithEmail:email:password:completion:.

Swift

Auth.auth().signIn(withEmail: email, password: password) { [weak self] user, error in
  guard let strongSelf = self else { return }
  // ...
}

Objective-C

[[FIRAuth auth] signInWithEmail:self->_emailField.text
                       password:self->_passwordField.text
                     completion:^(FIRAuthDataResult * _Nullable authResult,
                                  NSError * _Nullable error) {
  // ...
}];

If the user successfully signs in, you can get the user's account data from the result object that's passed to the callback method.

Next steps

After a user signs in for the first time, a new user account is created and linked to the credentials—that is, the user name and password, phone number, or auth provider information—the user signed in with. This new account is stored as part of your Firebase project, and can be used to identify a user across every app in your project, regardless of how the user signs in.

In your apps, you can get the user's basic profile information from the FIRUser object. See Manage Users.
In your Firebase Realtime Database and Cloud Storage Security Rules, you can get the signed-in user's unique user ID from the auth variable, and use it to control what data a user can access.

You can allow users to sign in to your app using multiple authentication providers by linking auth provider credentials to an existing user account.

To sign out a user, call signOut:.

Swift

    let firebaseAuth = Auth.auth()
do {
  try firebaseAuth.signOut()
} catch let signOutError as NSError {
  print ("Error signing out: %@", signOutError)
}

Objective-C

    NSError *signOutError;
BOOL status = [[FIRAuth auth] signOut:&signOutError];
if (!status) {
  NSLog(@"Error signing out: %@", signOutError);
  return;
}

You may also want to add error handling code for the full range of authentication errors. See Handle Errors.