Import Users

The Firebase Admin SDK provides the auth.importUsers() API for importing users in bulk to Firebase Authentication with elevated privileges. While this feature is also available in the Firebase CLI, the Admin SDK lets you upload existing users from an external authentication system or other Firebase project programmatically without having to create intermediate CSV or JSON files.

The user import API offers the following advantages:

  • Ability to migrate users from an external authentication system using a different password hashing algorithm.
  • Ability to migrate users from another Firebase project.
  • Optimization for speedy and efficient bulk import operations. This operation processes users without checking for uid, email, phoneNumber or other identifier duplication.
  • Ability to migrate existing or create new OAuth users (Google, Facebook, etc).
  • Ability to import users with custom claims directly in bulk.

Usage

Up to 1000 users can be imported in a single API call. Note that this operation is optimized for speed and does not check for uid, email, phoneNumber and other unique identifier duplication. Consequently, when you use this API, you must ensure that you do not duplicate any unique fields.

Node.js

// Up to 1000 users can be imported at once.
var userImportRecords = [
  {
    uid: 'uid1',
    email: 'user1@example.com',
    passwordHash: Buffer.from('passwordHash1'),
    passwordSalt: Buffer.from('salt1')
  },
  {
    uid: 'uid2',
    email: 'user2@example.com',
    passwordHash: Buffer.from('passwordHash2'),
    passwordSalt: Buffer.from('salt2')
  },
  ...
];

Java

// Up to 1000 users can be imported at once.
List<ImportUserRecord> users = new ArrayList<>();
users.add(ImportUserRecord.builder()
    .setUid("uid1")
    .setEmail("user1@example.com")
    .setPasswordHash("passwordHash1".getBytes())
    .setPasswordSalt("salt1".getBytes())
    .build());
users.add(ImportUserRecord.builder()
    .setUid("uid2")
    .setEmail("user2@example.com")
    .setPasswordHash("passwordHash2".getBytes())
    .setPasswordSalt("salt2".getBytes())
    .build());

Python

# Up to 1000 users can be imported at once.
users = [
    auth.ImportUserRecord(
        uid='uid1',
        email='user1@example.com',
        password_hash=b'password_hash_1',
        password_salt=b'salt1'
    ),
    auth.ImportUserRecord(
        uid='uid2',
        email='user2@example.com',
        password_hash=b'password_hash_2',
        password_salt=b'salt2'
    ),
]

Go

// Up to 1000 users can be imported at once.
var users []*auth.UserToImport
users = append(users, (&auth.UserToImport{}).
	UID("uid1").
	Email("user1@example.com").
	PasswordHash([]byte("passwordHash1")).
	PasswordSalt([]byte("salt1")))
users = append(users, (&auth.UserToImport{}).
	UID("uid2").
	Email("user2@example.com").
	PasswordHash([]byte("passwordHash2")).
	PasswordSalt([]byte("salt2")))

In this example, the hashing options are specified to help Firebase securely authenticate these users the next time they try to sign in with Firebase Authentication. On successful sign-in, Firebase re-hashes the user's password with the internal Firebase hashing algorithm. Learn more about the required fields per algorithm below.

Firebase Authentication attempts to upload the entire list of provided users even when a user-specific error occurs. The operation returns a result with the summary of successful and failed imports. Error details are returned per failed user import.

Node.js

var userImportOptions = {
  hash: {
    algorithm: 'HMAC_SHA256',
    key: Buffer.from('secretKey')
  }
};

admin.auth().importUsers(userImportRecords, userImportOptions)
  .then(function(userImportResult) {
    // The number of successful imports is determined via: userImportResult.successCount.
    // The number of failed imports is determined via: userImportResult.failureCount.
    // To get the error details.
    userImportResult.forEach(function(indexedError) {
        // The corresponding user that failed to upload.
        console.log(userImportRecords[indexedError.index].uid +' failed to import',
            indexedError.error);
    });
  })
  .catch(function(error) {
    // Some unrecoverable error occurred that prevented the operation from running.
  });

Java

UserImportOptions options = UserImportOptions.withHash(
    HmacSha256.builder()
        .setKey("secretKey".getBytes())
        .build());
try {
  UserImportResult result = FirebaseAuth.getInstance().importUsers(users, options);
  System.out.println("Successfully imported " + result.getSuccessCount() + " users");
  System.out.println("Failed to import " + result.getFailureCount() + " users");
  for (ErrorInfo indexedError : result.getErrors()) {
    System.out.println("Failed to import user at index: " + indexedError.getIndex()
        + " due to error: " + indexedError.getReason());
  }
} catch (FirebaseAuthException e) {
  // Some unrecoverable error occurred that prevented the operation from running.
}

Python

hash_alg = auth.UserImportHash.hmac_sha256(key=b'secret_key')
try:
    result = auth.import_users(users, hash_alg=hash_alg)
    print('Successfully imported {0} users. Failed to import {1} users.'.format(
        result.success_count, result.failure_count))
    for err in result.errors:
        print('Failed to import {0} due to {1}'.format(users[err.index].uid, err.reason))
except auth.AuthError:
    # Some unrecoverable error occurred that prevented the operation from running.
    pass

Go

client, err := app.Auth(ctx)
if err != nil {
	log.Fatalln("Error initializing Auth client", err)
}

h := hash.HMACSHA256{
	Key: []byte("secretKey"),
}
result, err := client.ImportUsers(ctx, users, auth.WithHash(h))
if err != nil {
	log.Fatalln("Unrecoverable error prevented the operation from running", err)
}

log.Printf("Successfully imported %d users\n", result.SuccessCount)
log.Printf("Failed to import %d users\n", result.FailureCount)
for _, e := range result.Errors {
	log.Printf("Failed to import user at index: %d due to error: %s\n", e.Index, e.Reason)
}

If no password hashing is needed (phone number, custom token user, OAuth user etc.), do not provide hashing options.

Import users with HMAC hashed passwords

HMAC hashing algorithms include: HMAC_MD5, HMAC_SHA1, HMAC_SHA256 and HMAC_SHA512. For these hashing algorithms, you must provide the hash signer key.

Node.js

admin.auth().importUsers([{
  uid: 'some-uid',
  email: 'user@example.com',
  // Must be provided in a byte buffer.
  passwordHash: Buffer.from('password-hash'),
  // Must be provided in a byte buffer.
  passwordSalt: Buffer.from('salt')
}], {
  hash: {
    algorithm: 'HMAC_SHA256',
    // Must be provided in a byte buffer.
    key: Buffer.from('secret')
  }
}).then(function(results) {
  results.errors.forEach(function(indexedError) {
    console.log('Error importing user ' + indexedError.index);
  });
}).catch(function(error) {
  console.log('Error importing users:', error);
});

Java

try {
  List<ImportUserRecord> users = Collections.singletonList(ImportUserRecord.builder()
      .setUid("some-uid")
      .setEmail("user@example.com")
      .setPasswordHash("password-hash".getBytes())
      .setPasswordSalt("salt".getBytes())
      .build());
  UserImportOptions options = UserImportOptions.withHash(
      HmacSha256.builder()
          .setKey("secret".getBytes())
          .build());
  UserImportResult result = FirebaseAuth.getInstance().importUsers(users, options);
  for (ErrorInfo indexedError : result.getErrors()) {
    System.out.println("Failed to import user: " + indexedError.getReason());
  }
} catch (FirebaseAuthException e) {
  System.out.println("Error importing users: " + e.getMessage());
}

Python

users = [
    auth.ImportUserRecord(
        uid='some-uid',
        email='user@example.com',
        password_hash=b'password_hash',
        password_salt=b'salt'
    ),
]

hash_alg = auth.UserImportHash.hmac_sha256(key=b'secret')
try:
    result = auth.import_users(users, hash_alg=hash_alg)
    for err in result.errors:
        print('Failed to import user:', err.reason)
except auth.AuthError as error:
    print('Error importing users:', error)

Go

users := []*auth.UserToImport{
	(&auth.UserToImport{}).
		UID("some-uid").
		Email("user@example.com").
		PasswordHash([]byte("password-hash")).
		PasswordSalt([]byte("salt")),
}
h := hash.HMACSHA256{
	Key: []byte("secret"),
}
result, err := client.ImportUsers(ctx, users, auth.WithHash(h))
if err != nil {
	log.Fatalln("Error importing users", err)
}
for _, e := range result.Errors {
	log.Println("Failed to import user", e.Reason)
}

Import users with MD5, SHA and PBKDF hashed passwords

MD5, SHA and PBKDF hashing algorithms include: MD5, SHA1, SHA256, SHA512, PBKDF_SHA1 and PBKDF2_SHA256. For these hashing algorithms, you must provide the number of rounds (between 0 and 120000) used to hash the password.

Node.js

admin.auth().importUsers([{
  uid: 'some-uid',
  email: 'user@example.com',
  // Must be provided in a byte buffer.
  passwordHash: Buffer.from('password-hash'),
  // Must be provided in a byte buffer.
  passwordSalt: Buffer.from('salt')
}], {
  hash: {
    algorithm: 'PBKDF2_SHA256',
    rounds: 100000
  }
}).then(function(results) {
  results.errors.forEach(function(indexedError) {
    console.log('Error importing user ' + indexedError.index);
  });
}).catch(function(error) {
  console.log('Error importing users:', error);
});

Java

try {
  List<ImportUserRecord> users = Collections.singletonList(ImportUserRecord.builder()
      .setUid("some-uid")
      .setEmail("user@example.com")
      .setPasswordHash("password-hash".getBytes())
      .setPasswordSalt("salt".getBytes())
      .build());
  UserImportOptions options = UserImportOptions.withHash(
      Pbkdf2Sha256.builder()
          .setRounds(100000)
          .build());
  UserImportResult result = FirebaseAuth.getInstance().importUsers(users, options);
  for (ErrorInfo indexedError : result.getErrors()) {
    System.out.println("Failed to import user: " + indexedError.getReason());
  }
} catch (FirebaseAuthException e) {
  System.out.println("Error importing users: " + e.getMessage());
}

Python

users = [
    auth.ImportUserRecord(
        uid='some-uid',
        email='user@example.com',
        password_hash=b'password_hash',
        password_salt=b'salt'
    ),
]

hash_alg = auth.UserImportHash.pbkdf2_sha256(rounds=100000)
try:
    result = auth.import_users(users, hash_alg=hash_alg)
    for err in result.errors:
        print('Failed to import user:', err.reason)
except auth.AuthError as error:
    print('Error importing users:', error)

Go

users := []*auth.UserToImport{
	(&auth.UserToImport{}).
		UID("some-uid").
		Email("user@example.com").
		PasswordHash([]byte("password-hash")).
		PasswordSalt([]byte("salt")),
}
h := hash.PBKDF2SHA256{
	Rounds: 100000,
}
result, err := client.ImportUsers(ctx, users, auth.WithHash(h))
if err != nil {
	log.Fatalln("Error importing users", err)
}
for _, e := range result.Errors {
	log.Println("Failed to import user", e.Reason)
}

Import users with standard SCRYPT hashed passwords

Firebase Authentication supports the standard SCRYPT algorithm as well as an internal modified version. For the standard SCRYPT algorithm, the following hashing parameters are required:

  • memoryCost: the CPU/memory cost of the hashing algorithm.
  • parallelization: the parallelization of the hashing algorithm.
  • blockSize: the block size (normally 8) of the hashing algorithm.
  • derivedKeyLength: The derived key length of the hashing algorithm

Node.js

admin.auth().importUsers([{
  uid: 'some-uid',
  email: 'user@example.com',
  // Must be provided in a byte buffer.
  passwordHash: Buffer.from('password-hash'),
  // Must be provided in a byte buffer.
  passwordSalt: Buffer.from('salt')
}], {
  hash: {
    algorithm: 'STANDARD_SCRYPT',
    memoryCost: 1024,
    parallelization: 16,
    blockSize: 8,
    derivedKeyLength: 64
  }
}).then(function(results) {
  results.errors.forEach(function(indexedError) {
    console.log('Error importing user ' + indexedError.index);
  });
}).catch(function(error) {
  console.log('Error importing users:', error);
});

Java

try {
  List<ImportUserRecord> users = Collections.singletonList(ImportUserRecord.builder()
      .setUid("some-uid")
      .setEmail("user@example.com")
      .setPasswordHash("password-hash".getBytes())
      .setPasswordSalt("salt".getBytes())
      .build());
  UserImportOptions options = UserImportOptions.withHash(
      StandardScrypt.builder()
          .setMemoryCost(1024)
          .setParallelization(16)
          .setBlockSize(8)
          .setDerivedKeyLength(64)
          .build());
  UserImportResult result = FirebaseAuth.getInstance().importUsers(users, options);
  for (ErrorInfo indexedError : result.getErrors()) {
    System.out.println("Failed to import user: " + indexedError.getReason());
  }
} catch (FirebaseAuthException e) {
  System.out.println("Error importing users: " + e.getMessage());
}

Python

users = [
    auth.ImportUserRecord(
        uid='some-uid',
        email='user@example.com',
        password_hash=b'password_hash',
        password_salt=b'salt'
    ),
]

hash_alg = auth.UserImportHash.standard_scrypt(
    memory_cost=1024, parallelization=16, block_size=8, derived_key_length=64)
try:
    result = auth.import_users(users, hash_alg=hash_alg)
    for err in result.errors:
        print('Failed to import user:', err.reason)
except auth.AuthError as error:
    print('Error importing users:', error)

Go

users := []*auth.UserToImport{
	(&auth.UserToImport{}).
		UID("some-uid").
		Email("user@example.com").
		PasswordHash([]byte("password-hash")).
		PasswordSalt([]byte("salt")),
}
h := hash.StandardScrypt{
	MemoryCost:       1024,
	Parallelization:  16,
	BlockSize:        8,
	DerivedKeyLength: 64,
}
result, err := client.ImportUsers(ctx, users, auth.WithHash(h))
if err != nil {
	log.Fatalln("Error importing users", err)
}
for _, e := range result.Errors {
	log.Println("Failed to import user", e.Reason)
}

Import users with BCRYPT hashed passwords

For BCRYPT hashed passwords, neither additional hash parameters, nor password salts per user are required.

Node.js

admin.auth().importUsers([{
  uid: 'some-uid',
  email: 'user@example.com',
  // Must be provided in a byte buffer.
  passwordHash: Buffer.from('password-hash')
}], {
  hash: {
    algorithm: 'BCRYPT'
  }
}).then(function(results) {
  results.errors.forEach(function(indexedError) {
    console.log('Error importing user ' + indexedError.index);
  });
}).catch(function(error) {
  console.log('Error importing users:', error);
});

Java

try {
  List<ImportUserRecord> users = Collections.singletonList(ImportUserRecord.builder()
      .setUid("some-uid")
      .setEmail("user@example.com")
      .setPasswordHash("password-hash".getBytes())
      .setPasswordSalt("salt".getBytes())
      .build());
  UserImportOptions options = UserImportOptions.withHash(Bcrypt.getInstance());
  UserImportResult result = FirebaseAuth.getInstance().importUsers(users, options);
  for (ErrorInfo indexedError : result.getErrors()) {
    System.out.println("Failed to import user: " + indexedError.getReason());
  }
} catch (FirebaseAuthException e) {
  System.out.println("Error importing users: " + e.getMessage());
}

Python

users = [
    auth.ImportUserRecord(
        uid='some-uid',
        email='user@example.com',
        password_hash=b'password_hash',
        password_salt=b'salt'
    ),
]

hash_alg = auth.UserImportHash.bcrypt()
try:
    result = auth.import_users(users, hash_alg=hash_alg)
    for err in result.errors:
        print('Failed to import user:', err.reason)
except auth.AuthError as error:
    print('Error importing users:', error)

Go

users := []*auth.UserToImport{
	(&auth.UserToImport{}).
		UID("some-uid").
		Email("user@example.com").
		PasswordHash([]byte("password-hash")).
		PasswordSalt([]byte("salt")),
}
h := hash.Bcrypt{}
result, err := client.ImportUsers(ctx, users, auth.WithHash(h))
if err != nil {
	log.Fatalln("Error importing users", err)
}
for _, e := range result.Errors {
	log.Println("Failed to import user", e.Reason)
}

Import users with Firebase SCRYPT hashed passwords

Importing passwords hashed with the modified Firebase version of the SCRYPT hashing algorithm is useful for migrating users from another existing Firebase project. In order to do so, the internal parameters need to be determined for the original project.

Firebase generates unique password hash parameters for each Firebase project. To access these parameters, navigate to the Users tab in the Firebase Console and select Password Hash Parameters from the drop down in the upper-right hand corner of the table list of users.

Parameters needed to construct the hash options for this algorithm include:

  • key: the signer key normally provided in base64 encoding.
  • saltSeparator: the salt separator normally provided in base64 encoding(optional).
  • rounds: the number of rounds used to hash the passwords.
  • memoryCost: the memory cost required for this algorithm.

Node.js

admin.auth().importUsers([{
  uid: 'some-uid',
  email: 'user@example.com',
  // Must be provided in a byte buffer.
  passwordHash: Buffer.from('base64-password-hash', 'base64'),
  // Must be provided in a byte buffer.
  passwordSalt: Buffer.from('base64-salt', 'base64')
}], {
  hash: {
    algorithm: 'SCRYPT',
    // All the parameters below can be obtained from the Firebase Console's users section.
    // Must be provided in a byte buffer.
    key: Buffer.from('base64-secret', 'base64'),
    saltSeparator: Buffer.from('base64SaltSeparator', 'base64'),
    rounds: 8,
    memoryCost: 14
  }
}).then(function(results) {
  results.errors.forEach(function(indexedError) {
    console.log('Error importing user ' + indexedError.index);
  });
}).catch(function(error) {
  console.log('Error importing users:', error);
});

Java

try {
  List<ImportUserRecord> users = Collections.singletonList(ImportUserRecord.builder()
      .setUid("some-uid")
      .setEmail("user@example.com")
      .setPasswordHash("password-hash".getBytes())
      .setPasswordSalt("salt".getBytes())
      .build());
  UserImportOptions options = UserImportOptions.withHash(
      Scrypt.builder()
          // All the parameters below can be obtained from the Firebase Console's "Users"
          // section. Base64 encoded parameters must be decoded into raw bytes.
          .setKey(BaseEncoding.base64().decode("base64-secret"))
          .setSaltSeparator(BaseEncoding.base64().decode("base64-salt-separator"))
          .setRounds(8)
          .setMemoryCost(14)
          .build());
  UserImportResult result = FirebaseAuth.getInstance().importUsers(users, options);
  for (ErrorInfo indexedError : result.getErrors()) {
    System.out.println("Failed to import user: " + indexedError.getReason());
  }
} catch (FirebaseAuthException e) {
  System.out.println("Error importing users: " + e.getMessage());
}

Python

users = [
    auth.ImportUserRecord(
        uid='some-uid',
        email='user@example.com',
        password_hash=b'password_hash',
        password_salt=b'salt'
    ),
]

# All the parameters below can be obtained from the Firebase Console's "Users"
# section. Base64 encoded parameters must be decoded into raw bytes.
hash_alg = auth.UserImportHash.scrypt(
    key=base64.b64decode('base64_secret'),
    salt_separator=base64.b64decode('base64_salt_separator'),
    rounds=8,
    memory_cost=14
)
try:
    result = auth.import_users(users, hash_alg=hash_alg)
    for err in result.errors:
        print('Failed to import user:', err.reason)
except auth.AuthError as error:
    print('Error importing users:', error)

Go

users := []*auth.UserToImport{
	(&auth.UserToImport{}).
		UID("some-uid").
		Email("user@example.com").
		PasswordHash([]byte("password-hash")).
		PasswordSalt([]byte("salt")),
}
b64decode := func(s string) []byte {
	b, err := base64.StdEncoding.DecodeString(s)
	if err != nil {
		log.Fatalln("Failed to decode string", err)
	}
	return b
}

// All the parameters below can be obtained from the Firebase Console's "Users"
// section. Base64 encoded parameters must be decoded into raw bytes.
h := hash.Scrypt{
	Key:           b64decode("base64-secret"),
	SaltSeparator: b64decode("base64-salt-separator"),
	Rounds:        8,
	MemoryCost:    14,
}
result, err := client.ImportUsers(ctx, users, auth.WithHash(h))
if err != nil {
	log.Fatalln("Error importing users", err)
}
for _, e := range result.Errors {
	log.Println("Failed to import user", e.Reason)
}

Import users without passwords

You can import users without passwords. Users without passwords can be imported in combination with users that have OAuth providers, custom claims and phone numbers, and so on.

Node.js

admin.auth().importUsers([{
  uid: 'some-uid',
  displayName: 'John Doe',
  email: 'johndoe@gmail.com',
  photoURL: 'http://www.example.com/12345678/photo.png',
  emailVerified: true,
  phoneNumber: '+11234567890',
  // Set this user as admin.
  customClaims: {admin: true},
  // User with Google provider.
  providerData: [{
    uid: 'google-uid',
    email: 'johndoe@gmail.com',
    displayName: 'John Doe',
    photoURL: 'http://www.example.com/12345678/photo.png',
    providerId: 'google.com'
  }]
}]).then(function(results) {
  results.errors.forEach(function(indexedError) {
    console.log('Error importing user ' + indexedError.index);
  });
}).catch(function(error) {
  console.log('Error importing users:', error);
});

Java

try {
  List<ImportUserRecord> users = Collections.singletonList(ImportUserRecord.builder()
      .setUid("some-uid")
      .setDisplayName("John Doe")
      .setEmail("johndoe@gmail.com")
      .setPhotoUrl("http://www.example.com/12345678/photo.png")
      .setEmailVerified(true)
      .setPhoneNumber("+11234567890")
      .putCustomClaim("admin", true) // set this user as admin
      .addUserProvider(UserProvider.builder() // user with Google provider
          .setUid("google-uid")
          .setEmail("johndoe@gmail.com")
          .setDisplayName("John Doe")
          .setPhotoUrl("http://www.example.com/12345678/photo.png")
          .setProviderId("google.com")
          .build())
      .build());
  UserImportResult result = FirebaseAuth.getInstance().importUsers(users);
  for (ErrorInfo indexedError : result.getErrors()) {
    System.out.println("Failed to import user: " + indexedError.getReason());
  }
} catch (FirebaseAuthException e) {
  System.out.println("Error importing users: " + e.getMessage());
}

Python

users = [
    auth.ImportUserRecord(
        uid='some-uid',
        display_name='John Doe',
        email='johndoe@gmail.com',
        photo_url='http://www.example.com/12345678/photo.png',
        email_verified=True,
        phone_number='+11234567890',
        custom_claims={'admin': True}, # set this user as admin
        provider_data=[ # user with Google provider
            auth.UserProvider(
                uid='google-uid',
                email='johndoe@gmail.com',
                display_name='John Doe',
                photo_url='http://www.example.com/12345678/photo.png',
                provider_id='google.com'
            )
        ],
    ),
]
try:
    result = auth.import_users(users)
    for err in result.errors:
        print('Failed to import user:', err.reason)
except auth.AuthError as error:
    print('Error importing users:', error)

Go

users := []*auth.UserToImport{
	(&auth.UserToImport{}).
		UID("some-uid").
		DisplayName("John Doe").
		Email("johndoe@gmail.com").
		PhotoURL("http://www.example.com/12345678/photo.png").
		EmailVerified(true).
		PhoneNumber("+11234567890").
		CustomClaims(map[string]interface{}{"admin": true}). // set this user as admin
		ProviderData([]*auth.UserProvider{                   // user with Google provider
			{
				UID:         "google-uid",
				Email:       "johndoe@gmail.com",
				DisplayName: "John Doe",
				PhotoURL:    "http://www.example.com/12345678/photo.png",
				ProviderID:  "google.com",
			},
		}),
}
result, err := client.ImportUsers(ctx, users)
if err != nil {
	log.Fatalln("Error importing users", err)
}
for _, e := range result.Errors {
	log.Println("Failed to import user", e.Reason)
}

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