Request Syntax Request Parameters Response Syntax Response Elements Errors Examples See Also

AdminInitiateAuth

Starts sign-in for applications with a server-side component, for example a traditional web application. This operation specifies the authentication flow that you'd like to begin. The authentication flow that you specify must be supported in your app client configuration. For more information about authentication flows, see Authentication flows.

Note

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 Services 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.

Note

Amazon Cognito evaluates Amazon 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

Request Syntax


{
   "AnalyticsMetadata": { 
      "AnalyticsEndpointId": "string"
   },
   "AuthFlow": "string",
   "AuthParameters": { 
      "string" : "string" 
   },
   "ClientId": "string",
   "ClientMetadata": { 
      "string" : "string" 
   },
   "ContextData": { 
      "EncodedData": "string",
      "HttpHeaders": [ 
         { 
            "headerName": "string",
            "headerValue": "string"
         }
      ],
      "IpAddress": "string",
      "ServerName": "string",
      "ServerPath": "string"
   },
   "Session": "string",
   "UserPoolId": "string"
}

Request Parameters

For information about the parameters that are common to all actions, see Common Parameters.

The request accepts the following data in JSON format.

AnalyticsMetadata

Information that supports analytics outcomes with Amazon Pinpoint, including the user's endpoint ID. The endpoint ID is a destination for Amazon Pinpoint push notifications, for example a device identifier, email address, or phone number.

Type: AnalyticsMetadataType object

Required: No

AuthFlow

The authentication flow that you want to initiate. Each AuthFlow has linked AuthParameters that you must submit. The following are some example flows.

Include the required AdminInitiateAuth:AuthParameters for the flow that you choose.

USER_AUTH: The entry point for choice-based authentication with passwords, one-time passwords, and WebAuthn authenticators. Request a preferred authentication type or review available authentication types. From the offered authentication types, select one in a challenge response and then authenticate with that method in an additional challenge response. To activate this setting, your user pool must be in the Essentials tier or higher.
USER_SRP_AUTH: Username-password authentication with the Secure Remote Password (SRP) protocol. For more information, see Use SRP password verification in custom authentication flow.
REFRESH_TOKEN_AUTH and REFRESH_TOKEN: Receive new ID and access tokens when you pass a REFRESH_TOKEN parameter with a valid refresh token as the value. For more information, see Using the refresh token.
CUSTOM_AUTH: Custom authentication with Lambda triggers. For more information, see Custom authentication challenge Lambda triggers.
ADMIN_USER_PASSWORD_AUTH: Server-side username-password authentication with the password sent directly in the request. For more information about client-side and server-side authentication, see SDK authorization models.

USER_PASSWORD_AUTH is a flow type of InitiateAuth and isn't valid for AdminInitiateAuth.

Type: String

Required: Yes

AuthParameters

The authentication parameters. These are inputs corresponding to the AuthFlow that you're invoking. The required values depend on the value of AuthFlow for example:

For USER_AUTH: USERNAME (required), PREFERRED_CHALLENGE. If you don't provide a value for PREFERRED_CHALLENGE, Amazon Cognito responds with the AvailableChallenges parameter that specifies the available sign-in methods.
For USER_SRP_AUTH: USERNAME (required), SRP_A (required), SECRET_HASH (required if the app client is configured with a client secret), DEVICE_KEY.
For ADMIN_USER_PASSWORD_AUTH: USERNAME (required), PASSWORD (required), SECRET_HASH (required if the app client is configured with a client secret), DEVICE_KEY.
For REFRESH_TOKEN_AUTH/REFRESH_TOKEN: REFRESH_TOKEN (required), SECRET_HASH (required if the app client is configured with a client secret), DEVICE_KEY.
For CUSTOM_AUTH: USERNAME (required), SECRET_HASH (if app client is configured with client secret), DEVICE_KEY. To start the authentication flow with password verification, include ChallengeName: SRP_A and SRP_A: (The SRP_A Value).

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.

Type: String to string map

Key Length Constraints: Minimum length of 0. Maximum length of 131072.

Value Length Constraints: Minimum length of 0. Maximum length of 131072.

Required: No

ClientId

The ID of the app client where the user wants to sign in.

Type: String

Length Constraints: Minimum length of 1. Maximum length of 128.

Pattern: [\w+]+

Required: Yes

ClientMetadata

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

You create custom workflows by assigning Amazon Lambda functions to user pool triggers. When you use the AdminInitiateAuth API action, Amazon Cognito invokes the Lambda functions that are specified for various triggers. The ClientMetadata value is passed as input to the functions for only the following triggers:

Pre signup
Pre authentication
User migration

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

When you use the AdminInitiateAuth API action, Amazon Cognito also invokes the functions for the following triggers, but it doesn't provide the ClientMetadata value as input:

Post authentication
Custom message
Pre token generation
Create auth challenge
Define auth challenge
Custom email sender
Custom SMS sender

For more information, see Using Lambda triggers in the Amazon Cognito Developer Guide.

Note

When you use the ClientMetadata parameter, note that Amazon Cognito won't do the following:

Store the ClientMetadata value. This data is available only to Amazon 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 send sensitive information in this parameter.

Type: String to string map

Key Length Constraints: Minimum length of 0. Maximum length of 131072.

Value Length Constraints: Minimum length of 0. Maximum length of 131072.

Required: No

ContextData

Contextual data about your user session like the device fingerprint, IP address, or location. Amazon Cognito threat protection 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.

For more information, see Collecting data for threat protection in applications.

Type: ContextDataType object

Required: No

Session

The optional session ID from a ConfirmSignUp API request. You can sign in a user directly from the sign-up process with an AuthFlow of USER_AUTH and AuthParameters of EMAIL_OTP or SMS_OTP, depending on how your user pool sent the confirmation-code message.

Type: String

Length Constraints: Minimum length of 20. Maximum length of 2048.

Required: No

UserPoolId

The ID of the user pool where the user wants to sign in.

Type: String

Length Constraints: Minimum length of 1. Maximum length of 55.

Pattern: [\w-]+_[0-9a-zA-Z]+

Required: Yes

Response Syntax


{
   "AuthenticationResult": { 
      "AccessToken": "string",
      "ExpiresIn": number,
      "IdToken": "string",
      "NewDeviceMetadata": { 
         "DeviceGroupKey": "string",
         "DeviceKey": "string"
      },
      "RefreshToken": "string",
      "TokenType": "string"
   },
   "AvailableChallenges": [ "string" ],
   "ChallengeName": "string",
   "ChallengeParameters": { 
      "string" : "string" 
   },
   "Session": "string"
}

Response Elements

If the action is successful, the service sends back an HTTP 200 response.

The following data is returned in JSON format by the service.

AuthenticationResult

The outcome of successful authentication. This is only returned if the user pool has no additional challenges to return. If Amazon Cognito returns another challenge, the response includes ChallengeName, ChallengeParameters, and Session so that your user can answer the challenge.

Type: AuthenticationResultType object

AvailableChallenges

This response parameter lists the available authentication challenges that users can select from in choice-based authentication. For example, they might be able to choose between passkey authentication, a one-time password from an SMS message, and a traditional password.

Type: Array of strings

ChallengeName

The name of the challenge that you're responding to with this call. This is returned in the AdminInitiateAuth response if you must pass another challenge.

Possible challenges include the following:

Note

All of the following challenges require USERNAME and, when the app client has a client secret, SECRET_HASH in the parameters.

WEB_AUTHN: Respond to the challenge with the results of a successful authentication with a WebAuthn authenticator, or passkey. Examples of WebAuthn authenticators include biometric devices and security keys.
PASSWORD: Respond with USER_PASSWORD_AUTH parameters: USERNAME (required), PASSWORD (required), SECRET_HASH (required if the app client is configured with a client secret), DEVICE_KEY.
PASSWORD_SRP: Respond with USER_SRP_AUTH parameters: USERNAME (required), SRP_A (required), SECRET_HASH (required if the app client is configured with a client secret), DEVICE_KEY.
SELECT_CHALLENGE: Respond to the challenge with USERNAME and an ANSWER that matches one of the challenge types in the AvailableChallenges response parameter.
SMS_MFA: Respond with an SMS_MFA_CODE that your user pool delivered in an SMS message.
EMAIL_OTP: Respond with an EMAIL_OTP_CODE that your user pool delivered in an email message.
PASSWORD_VERIFIER: Respond with PASSWORD_CLAIM_SIGNATURE, PASSWORD_CLAIM_SECRET_BLOCK, and TIMESTAMP after client-side SRP calculations.
CUSTOM_CHALLENGE: This is returned if your custom authentication flow determines that the user should pass another challenge before tokens are issued. The parameters of the challenge are determined by your Lambda function.
DEVICE_SRP_AUTH: Respond with the initial parameters of device SRP authentication. For more information, see Signing in with a device.
DEVICE_PASSWORD_VERIFIER: Respond with PASSWORD_CLAIM_SIGNATURE, PASSWORD_CLAIM_SECRET_BLOCK, and TIMESTAMP after client-side SRP calculations. For more information, see Signing in with a device.
NEW_PASSWORD_REQUIRED: For users who are required to change their passwords after successful first login. Respond to this challenge with NEW_PASSWORD and any required attributes that Amazon Cognito returned in the requiredAttributes parameter. You can also set values for attributes that aren't required by your user pool and that your app client can write.

Amazon Cognito only returns this challenge for users who have temporary passwords. When you create passwordless users, you must provide values for all required attributes.

Note
In a NEW_PASSWORD_REQUIRED challenge response, you can't modify a required attribute that already has a value. In AdminRespondToAuthChallenge or RespondToAuthChallenge, set a value for any keys that Amazon Cognito returned in the requiredAttributes parameter, then use the AdminUpdateUserAttributes or UpdateUserAttributes API operation to modify the value of any additional attributes.
MFA_SETUP: For users who are required to setup an MFA factor before they can sign in. The MFA types activated for the user pool will be listed in the challenge parameters MFAS_CAN_SETUP value.

To set up time-based one-time password (TOTP) MFA, use the session returned in this challenge from InitiateAuth or AdminInitiateAuth as an input to AssociateSoftwareToken. Then, use the session returned by VerifySoftwareToken as an input to RespondToAuthChallenge or AdminRespondToAuthChallenge with challenge name MFA_SETUP to complete sign-in.

To set up SMS or email MFA, collect a phone_number or email attribute for the user. Then restart the authentication flow with an InitiateAuth or AdminInitiateAuth request.

Type: String

ChallengeParameters

The parameters of an authentication challenge. Amazon Cognito returns challenge parameters as a guide to the responses your user or application must provide for the returned ChallengeName. Calculate responses to the challenge parameters and pass them in the ChallengeParameters of AdminRespondToAuthChallenge.

All challenges require USERNAME and, when the app client has a client secret, SECRET_HASH.

In SRP challenges, Amazon Cognito returns the username attribute in USER_ID_FOR_SRP instead of any email address, preferred username, or phone number alias that you might have specified in your AdminInitiateAuth request. You must use the username and not an alias in the ChallengeResponses of your challenge response.

Type: String to string map

Key Length Constraints: Minimum length of 0. Maximum length of 131072.

Value Length Constraints: Minimum length of 0. Maximum length of 131072.

Session

The session that must be passed to challenge-response requests. If an AdminInitiateAuth or AdminRespondToAuthChallenge API request results in another authentication challenge, Amazon Cognito returns a session ID and the parameters of the next challenge. Pass this session ID in the Session parameter of AdminRespondToAuthChallenge.

Type: String

Length Constraints: Minimum length of 20. Maximum length of 2048.

Errors

For information about the errors that are common to all actions, see Common Errors.

InternalErrorException

This exception is thrown when Amazon Cognito encounters an internal error.

HTTP Status Code: 500

InvalidEmailRoleAccessPolicyException

This exception is thrown when Amazon Cognito isn't allowed to use your email identity. HTTP status code: 400.

HTTP Status Code: 400

InvalidLambdaResponseException

This exception is thrown when Amazon Cognito encounters an invalid Amazon Lambda response.

HTTP Status Code: 400

InvalidParameterException

This exception is thrown when the Amazon Cognito service encounters an invalid parameter.

HTTP Status Code: 400

InvalidSmsRoleAccessPolicyException

This exception is returned when the role provided for SMS configuration doesn't have permission to publish using Amazon SNS.

HTTP Status Code: 400

InvalidSmsRoleTrustRelationshipException

This exception is thrown when the trust relationship is not valid for the role provided for SMS configuration. This can happen if you don't trust cognito-idp.amazonaws.com or the external ID provided in the role does not match what is provided in the SMS configuration for the user pool.

HTTP Status Code: 400

InvalidUserPoolConfigurationException

This exception is thrown when the user pool configuration is not valid.

HTTP Status Code: 400

MFAMethodNotFoundException

This exception is thrown when Amazon Cognito can't find a multi-factor authentication (MFA) method.

HTTP Status Code: 400

NotAuthorizedException

This exception is thrown when a user isn't authorized.

HTTP Status Code: 400

PasswordResetRequiredException

This exception is thrown when a password reset is required.

HTTP Status Code: 400

ResourceNotFoundException

This exception is thrown when the Amazon Cognito service can't find the requested resource.

HTTP Status Code: 400

TooManyRequestsException

This exception is thrown when the user has made too many requests for a given operation.

HTTP Status Code: 400

UnexpectedLambdaException

This exception is thrown when Amazon Cognito encounters an unexpected exception with Amazon Lambda.

HTTP Status Code: 400

UnsupportedOperationException

Exception that is thrown when you attempt to perform an operation that isn't enabled for the user pool client.

HTTP Status Code: 400

UserLambdaValidationException

This exception is thrown when the Amazon Cognito service encounters a user validation exception with the Amazon Lambda service.

HTTP Status Code: 400

UserNotConfirmedException

This exception is thrown when a user isn't confirmed successfully.

HTTP Status Code: 400

UserNotFoundException

This exception is thrown when a user isn't found.

HTTP Status Code: 400

Examples

Example

The following example request signs in the user "testuser" to an app client with a client secret. It includes context data for advanced security features and ClientMetadata for Lambda triggers. The device key and device group key in the response indicate that this user pool supports the device-remembering feature.

Sample Request


POST HTTP/1.1
Host: cognito-idp.us-west-2.amazonaws.com
X-Amz-Date: 20230613T200059Z
Accept-Encoding: gzip, deflate, br
X-Amz-Target: AWSCognitoIdentityProviderService.AdminInitiateAuth
User-Agent: <UserAgentString>
Authorization: AWS4-HMAC-SHA256 Credential=<Credential>, SignedHeaders=<Headers>, Signature=<Signature>
Content-Length: <PayloadSizeBytes>
{
    "AuthFlow": "ADMIN_USER_PASSWORD_AUTH",
    "ClientId": "1example23456789",
    "UserPoolId": "us-west-2_EXAMPLE",
    "AuthParameters": {
        "USERNAME": "testuser",
        "PASSWORD": "TestUserPassword1=",
        "SECRET_HASH": "cKtx2L2fvV1FeAbk3iUPgCyXY+5B0ItO0ItxhFaLkeA="
    },
    "ContextData": { 
      "EncodedData": "VGhpc0lzTXlFbmNvZGVkRGF0YQ",
      "HttpHeaders": [ 
         { 
            "headerName": "Referer",
            "headerValue": "https://home.example.com"
         }
      ],
      "IpAddress": "192.0.2.100",
      "ServerName": "auth.example.com",
      "ServerPath": "/web/private/program.html"
    },
    "ClientMetadata": {
        "MyTestKey": "MyTestValue"
    }
}

Sample Response


HTTP/1.1 200 OK
Date: Tue, 13 Jun 2023 20:00:59 GMT
Content-Type: application/x-amz-json-1.0
Content-Length: <PayloadSizeBytes>
x-amzn-requestid: a1b2c3d4-e5f6-a1b2-c3d4-EXAMPLE11111
Connection: keep-alive
{
	"AuthenticationResult": {
		"AccessToken": "eyJraACCESSEXAMPLE...",
		"ExpiresIn": 3600,
		"IdToken": "eyJraIDEXAMPLE...",
		"NewDeviceMetadata": {
			"DeviceGroupKey": "-v7w9UcY6",
			"DeviceKey": "us-west-2_a1b2c3d4-5678-90ab-cdef-EXAMPLE22222"
		},
		"RefreshToken": "eyJjREFRESHEXAMPLE...",
		"TokenType": "Bearer"
	},
	"ChallengeParameters": {}
}