[ aws . cognito-idp ]



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. A RespondToAuthChallenge 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 .


Amazon Cognito doesn’t evaluate Identity and Access Management (IAM) policies in requests for this API operation. For this operation, you can’t use IAM credentials to authorize requests, and you can’t grant IAM permissions in policies. For more information about authorization models in Amazon Cognito, see Using the Amazon Cognito user pools API and user pool endpoints .


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 .

See also: AWS API Documentation


--client-id <value>
--challenge-name <value>
[--session <value>]
[--challenge-responses <value>]
[--analytics-metadata <value>]
[--user-context-data <value>]
[--client-metadata <value>]
[--cli-input-json | --cli-input-yaml]
[--generate-cli-skeleton <value>]
[--endpoint-url <value>]
[--output <value>]
[--query <value>]
[--profile <value>]
[--region <value>]
[--version <value>]
[--color <value>]
[--ca-bundle <value>]
[--cli-read-timeout <value>]
[--cli-connect-timeout <value>]
[--cli-binary-format <value>]


--client-id (string)

The app client ID.

--challenge-name (string)

The challenge name. For more information, see InitiateAuth .

ADMIN_NO_SRP_AUTH isn’t a valid value.

Possible values:


--session (string)

The session that should be passed both ways in challenge-response calls to the service. If InitiateAuth or RespondToAuthChallenge API call determines that 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.

--challenge-responses (map)

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 .

key -> (string)

value -> (string)

Shorthand Syntax:


JSON Syntax:

{"string": "string"

--analytics-metadata (structure)

The Amazon Pinpoint analytics metadata that contributes to your metrics for RespondToAuthChallenge calls.

AnalyticsEndpointId -> (string)

The endpoint ID.

Shorthand Syntax:


JSON Syntax:

  "AnalyticsEndpointId": "string"

--user-context-data (structure)

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)

The source IP address of your user’s device.

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 .

Shorthand Syntax:


JSON Syntax:

  "IpAddress": "string",
  "EncodedData": "string"

--client-metadata (map)

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 RespondToAuthChallenge API action, Amazon Cognito invokes any functions that are assigned to the following triggers: post authentication , pre token generation , define auth challenge , create auth challenge , and verify auth challenge . 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, which provides the data that you assigned to the ClientMetadata parameter in your RespondToAuthChallenge 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.

key -> (string)

value -> (string)

Shorthand Syntax:


JSON Syntax:

{"string": "string"

--cli-input-json | --cli-input-yaml (string) Reads arguments from the JSON string provided. The JSON string follows the format provided by --generate-cli-skeleton. If other arguments are provided on the command line, those values will override the JSON-provided values. It is not possible to pass arbitrary binary values using a JSON-provided value as the string will be taken literally. This may not be specified along with --cli-input-yaml.

--generate-cli-skeleton (string) Prints a JSON skeleton to standard output without sending an API request. If provided with no value or the value input, prints a sample input JSON that can be used as an argument for --cli-input-json. Similarly, if provided yaml-input it will print a sample input YAML that can be used with --cli-input-yaml. If provided with the value output, it validates the command inputs and returns a sample output JSON for that command. The generated JSON skeleton is not stable between versions of the AWS CLI and there are no backwards compatibility guarantees in the JSON skeleton generated.

Global Options

--debug (boolean)

Turn on debug logging.

--endpoint-url (string)

Override command’s default URL with the given URL.

--no-verify-ssl (boolean)

By default, the AWS CLI uses SSL when communicating with AWS services. For each SSL connection, the AWS CLI will verify SSL certificates. This option overrides the default behavior of verifying SSL certificates.

--no-paginate (boolean)

Disable automatic pagination.

--output (string)

The formatting style for command output.

  • json
  • text
  • table
  • yaml
  • yaml-stream

--query (string)

A JMESPath query to use in filtering the response data.

--profile (string)

Use a specific profile from your credential file.

--region (string)

The region to use. Overrides config/env settings.

--version (string)

Display the version of this tool.

--color (string)

Turn on/off color output.

  • on
  • off
  • auto

--no-sign-request (boolean)

Do not sign requests. Credentials will not be loaded if this argument is provided.

--ca-bundle (string)

The CA certificate bundle to use when verifying SSL certificates. Overrides config/env settings.

--cli-read-timeout (int)

The maximum socket read time in seconds. If the value is set to 0, the socket read will be blocking and not timeout. The default value is 60 seconds.

--cli-connect-timeout (int)

The maximum socket connect time in seconds. If the value is set to 0, the socket connect will be blocking and not timeout. The default value is 60 seconds.

--cli-binary-format (string)

The formatting style to be used for binary blobs. The default format is base64. The base64 format expects binary blobs to be provided as a base64 encoded string. The raw-in-base64-out format preserves compatibility with AWS CLI V1 behavior and binary values must be passed literally. When providing contents from a file that map to a binary blob fileb:// will always be treated as binary and use the file contents directly regardless of the cli-binary-format setting. When using file:// the file contents will need to properly formatted for the configured cli-binary-format.

  • base64
  • raw-in-base64-out

--no-cli-pager (boolean)

Disable cli pager for output.

--cli-auto-prompt (boolean)

Automatically prompt for CLI input parameters.

--no-cli-auto-prompt (boolean)

Disable automatically prompt for CLI input parameters.



To use the following examples, you must have the AWS CLI installed and configured. See the Getting started guide in the AWS CLI User Guide for more information.

Unless otherwise stated, all examples have unix-like quotation rules. These examples will need to be adapted to your terminal’s quoting rules. See Using quotation marks with strings in the AWS CLI User Guide .

To respond to an authorization challenge

This example responds to an authorization challenge initiated with initiate-auth. It is a response to the NEW_PASSWORD_REQUIRED challenge. It sets a password for user jane@example.com.


aws cognito-idp respond-to-auth-challenge --client-id 3n4b5urk1ft4fl3mg5e62d9ado --challenge-name NEW_PASSWORD_REQUIRED --challenge-responses USERNAME=jane@example.com,NEW_PASSWORD="password" --session "SESSION_TOKEN"


  "ChallengeParameters": {},
  "AuthenticationResult": {
      "AccessToken": "ACCESS_TOKEN",
      "ExpiresIn": 3600,
      "TokenType": "Bearer",
      "RefreshToken": "REFRESH_TOKEN",
      "IdToken": "ID_TOKEN",
      "NewDeviceMetadata": {
          "DeviceKey": "us-west-2_fec070d2-fa88-424a-8ec8-b26d7198eb23",
          "DeviceGroupKey": "-wt2ha1Zd"


ChallengeName -> (string)

The challenge name. For more information, see InitiateAuth .

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 -> (map)

The challenge parameters. For more information, see InitiateAuth .

key -> (string)

value -> (string)

AuthenticationResult -> (structure)

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

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 -> (structure)

The new device metadata from an authentication result.

DeviceKey -> (string)

The device key.

DeviceGroupKey -> (string)

The device group key.