CognitoIdentityProvider / Client / admin_respond_to_auth_challenge



Some API operations in a user pool generate a challenge, like a prompt for an MFA code, for device authentication that bypasses MFA, or for a custom authentication challenge. An AdminRespondToAuthChallenge API request provides the answer to that challenge, like a code or a secure remote password (SRP). The parameters of a response to an authentication challenge vary with the type of challenge.

For more information about custom authentication challenges, see Custom authentication challenge Lambda triggers.


This action might generate an SMS text message. Starting June 1, 2021, US telecom carriers require you to register an origination phone number before you can send SMS messages to US phone numbers. If you use SMS text messages in Amazon Cognito, you must register a phone number with Amazon Pinpoint. Amazon Cognito uses the registered number automatically. Otherwise, Amazon Cognito users who must receive SMS messages might not be able to sign up, activate their accounts, or sign in.

If you have never used SMS text messages with Amazon Cognito or any other Amazon Web Service, Amazon Simple Notification Service might place your account in the SMS sandbox. In sandbox mode , you can send messages only to verified phone numbers. After you test your app while in the sandbox environment, you can move out of the sandbox and into production. For more information, see SMS message settings for Amazon Cognito user pools in the Amazon Cognito Developer Guide.


Amazon Cognito evaluates Identity and Access Management (IAM) policies in requests for this API operation. For this operation, you must use IAM credentials to authorize requests, and you must grant yourself the corresponding IAM permission in a policy.

Learn more

See also: AWS API Documentation

Request Syntax

response = client.admin_respond_to_auth_challenge(
        'string': 'string'
        'AnalyticsEndpointId': 'string'
        'IpAddress': 'string',
        'ServerName': 'string',
        'ServerPath': 'string',
        'HttpHeaders': [
                'headerName': 'string',
                'headerValue': 'string'
        'EncodedData': 'string'
        'string': 'string'
  • UserPoolId (string) –


    The ID of the Amazon Cognito user pool.

  • ClientId (string) –


    The app client ID.

  • ChallengeName (string) –


    The challenge name. For more information, see AdminInitiateAuth.

  • ChallengeResponses (dict) –

    The responses to the challenge that you received in the previous request. Each challenge has its own required response parameters. The following examples are partial JSON request bodies that highlight challenge-response parameters.


    You must provide a SECRET_HASH parameter in all challenge responses to an app client that has a client secret.


    "ChallengeName": "SMS_MFA", "ChallengeResponses": {"SMS_MFA_CODE": "[SMS_code]", "USERNAME": "[username]"}


    "ChallengeName": "PASSWORD_VERIFIER", "ChallengeResponses": {"PASSWORD_CLAIM_SIGNATURE": "[claim_signature]", "PASSWORD_CLAIM_SECRET_BLOCK": "[secret_block]", "TIMESTAMP": [timestamp], "USERNAME": "[username]"}

    Add "DEVICE_KEY" when you sign in with a remembered device.


    "ChallengeName": "CUSTOM_CHALLENGE", "ChallengeResponses": {"USERNAME": "[username]", "ANSWER": "[challenge_answer]"}

    Add "DEVICE_KEY" when you sign in with a remembered device.


    "ChallengeName": "NEW_PASSWORD_REQUIRED", "ChallengeResponses": {"NEW_PASSWORD": "[new_password]", "USERNAME": "[username]"}

    To set any required attributes that InitiateAuth returned in an requiredAttributes parameter, add "userAttributes.[attribute_name]": "[attribute_value]". This parameter can also set values for writable attributes that aren’t required by your user pool.


    In a NEW_PASSWORD_REQUIRED challenge response, you can’t modify a required attribute that already has a value. In RespondToAuthChallenge, set a value for any keys that Amazon Cognito returned in the requiredAttributes parameter, then use the UpdateUserAttributes API operation to modify the value of any additional attributes.


    "ChallengeName": "SOFTWARE_TOKEN_MFA", "ChallengeResponses": {"USERNAME": "[username]", "SOFTWARE_TOKEN_MFA_CODE": [authenticator_code]}


    "ChallengeName": "DEVICE_SRP_AUTH", "ChallengeResponses": {"USERNAME": "[username]", "DEVICE_KEY": "[device_key]", "SRP_A": "[srp_a]"}


    "ChallengeName": "DEVICE_PASSWORD_VERIFIER", "ChallengeResponses": {"DEVICE_KEY": "[device_key]", "PASSWORD_CLAIM_SIGNATURE": "[claim_signature]", "PASSWORD_CLAIM_SECRET_BLOCK": "[secret_block]", "TIMESTAMP": [timestamp], "USERNAME": "[username]"}


    "ChallengeName": "MFA_SETUP", "ChallengeResponses": {"USERNAME": "[username]"}, "SESSION": "[Session ID from VerifySoftwareToken]"


    "ChallengeName": "SELECT_MFA_TYPE", "ChallengeResponses": {"USERNAME": "[username]", "ANSWER": "[SMS_MFA or SOFTWARE_TOKEN_MFA]"}

    For more information about SECRET_HASH, see Computing secret hash values. For information about DEVICE_KEY, see Working with user devices in your user pool.

    • (string) –

      • (string) –

  • Session (string) – The session that should be passed both ways in challenge-response calls to the service. If an InitiateAuth or RespondToAuthChallenge API call determines that the caller must pass another challenge, it returns a session with other challenge parameters. This session should be passed as it is to the next RespondToAuthChallenge API call.

  • AnalyticsMetadata (dict) –

    The analytics metadata for collecting Amazon Pinpoint metrics for AdminRespondToAuthChallenge calls.

    • AnalyticsEndpointId (string) –

      The endpoint ID.

  • ContextData (dict) –

    Contextual data about your user session, such as the device fingerprint, IP address, or location. Amazon Cognito advanced security evaluates the risk of an authentication event based on the context that your app generates and passes to Amazon Cognito when it makes API requests.

    • IpAddress (string) – [REQUIRED]

      The source IP address of your user’s device.

    • ServerName (string) – [REQUIRED]

      Your server endpoint where this API is invoked.

    • ServerPath (string) – [REQUIRED]

      Your server path where this API is invoked.

    • HttpHeaders (list) – [REQUIRED]

      HttpHeaders received on your server in same order.

      • (dict) –

        The HTTP header.

        • headerName (string) –

          The header name.

        • headerValue (string) –

          The header value.

    • EncodedData (string) –

      Encoded device-fingerprint details that your app collected with the Amazon Cognito context data collection library. For more information, see Adding user device and session data to API requests.

  • ClientMetadata (dict) –

    A map of custom key-value pairs that you can provide as input for any custom workflows that this action triggers.

    You create custom workflows by assigning Lambda functions to user pool triggers. When you use the AdminRespondToAuthChallenge API action, Amazon Cognito invokes any functions that you have assigned to the following triggers:

    • pre sign-up

    • custom message

    • post authentication

    • user migration

    • pre token generation

    • define auth challenge

    • create auth challenge

    • verify auth challenge response

    When Amazon Cognito invokes any of these functions, it passes a JSON payload, which the function receives as input. This payload contains a clientMetadata attribute that provides the data that you assigned to the ClientMetadata parameter in your AdminRespondToAuthChallenge request. In your function code in Lambda, you can process the clientMetadata value to enhance your workflow for your specific needs.

    For more information, see Customizing user pool Workflows with Lambda Triggers in the Amazon Cognito Developer Guide.


    When you use the ClientMetadata parameter, remember that Amazon Cognito won’t do the following:

    • Store the ClientMetadata value. This data is available only to Lambda triggers that are assigned to a user pool to support custom workflows. If your user pool configuration doesn’t include triggers, the ClientMetadata parameter serves no purpose.

    • Validate the ClientMetadata value.

    • Encrypt the ClientMetadata value. Don’t use Amazon Cognito to provide sensitive information.

    • (string) –

      • (string) –

Return type:



Response Syntax

    'Session': 'string',
    'ChallengeParameters': {
        'string': 'string'
    'AuthenticationResult': {
        'AccessToken': 'string',
        'ExpiresIn': 123,
        'TokenType': 'string',
        'RefreshToken': 'string',
        'IdToken': 'string',
        'NewDeviceMetadata': {
            'DeviceKey': 'string',
            'DeviceGroupKey': 'string'

Response Structure

  • (dict) –

    Responds to the authentication challenge, as an administrator.

    • ChallengeName (string) –

      The name of the challenge. For more information, see AdminInitiateAuth.

    • Session (string) –

      The session that should be passed both ways in challenge-response calls to the service. If the caller must pass another challenge, they return a session with other challenge parameters. This session should be passed as it is to the next RespondToAuthChallenge API call.

    • ChallengeParameters (dict) –

      The challenge parameters. For more information, see AdminInitiateAuth.

      • (string) –

        • (string) –

    • AuthenticationResult (dict) –

      The result returned by the server in response to the authentication request.

      • AccessToken (string) –

        A valid access token that Amazon Cognito issued to the user who you want to authenticate.

      • ExpiresIn (integer) –

        The expiration period of the authentication result in seconds.

      • TokenType (string) –

        The token type.

      • RefreshToken (string) –

        The refresh token.

      • IdToken (string) –

        The ID token.

      • NewDeviceMetadata (dict) –

        The new device metadata from an authentication result.

        • DeviceKey (string) –

          The device key.

        • DeviceGroupKey (string) –

          The device group key.


  • CognitoIdentityProvider.Client.exceptions.ResourceNotFoundException

  • CognitoIdentityProvider.Client.exceptions.InvalidParameterException

  • CognitoIdentityProvider.Client.exceptions.NotAuthorizedException

  • CognitoIdentityProvider.Client.exceptions.CodeMismatchException

  • CognitoIdentityProvider.Client.exceptions.ExpiredCodeException

  • CognitoIdentityProvider.Client.exceptions.UnexpectedLambdaException

  • CognitoIdentityProvider.Client.exceptions.InvalidPasswordException

  • CognitoIdentityProvider.Client.exceptions.UserLambdaValidationException

  • CognitoIdentityProvider.Client.exceptions.InvalidLambdaResponseException

  • CognitoIdentityProvider.Client.exceptions.TooManyRequestsException

  • CognitoIdentityProvider.Client.exceptions.InvalidUserPoolConfigurationException

  • CognitoIdentityProvider.Client.exceptions.InternalErrorException

  • CognitoIdentityProvider.Client.exceptions.MFAMethodNotFoundException

  • CognitoIdentityProvider.Client.exceptions.InvalidSmsRoleAccessPolicyException

  • CognitoIdentityProvider.Client.exceptions.InvalidSmsRoleTrustRelationshipException

  • CognitoIdentityProvider.Client.exceptions.AliasExistsException

  • CognitoIdentityProvider.Client.exceptions.PasswordResetRequiredException

  • CognitoIdentityProvider.Client.exceptions.UserNotFoundException

  • CognitoIdentityProvider.Client.exceptions.UserNotConfirmedException

  • CognitoIdentityProvider.Client.exceptions.SoftwareTokenMFANotFoundException