CreateFaceLivenessSession - Amazon Rekognition


This API operation initiates a Face Liveness session. It returns a SessionId, which you can use to start streaming Face Liveness video and get the results for a Face Liveness session.

You can use the OutputConfig option in the Settings parameter to provide an Amazon S3 bucket location. The Amazon S3 bucket stores reference images and audit images. If no Amazon S3 bucket is defined, raw bytes are sent instead.

You can use AuditImagesLimit to limit the number of audit images returned when GetFaceLivenessSessionResults is called. This number is between 0 and 4. By default, it is set to 0. The limit is best effort and based on the duration of the selfie-video.

Request Syntax

{ "ClientRequestToken": "string", "KmsKeyId": "string", "Settings": { "AuditImagesLimit": number, "OutputConfig": { "S3Bucket": "string", "S3KeyPrefix": "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.


Idempotent token is used to recognize the Face Liveness request. If the same token is used with multiple CreateFaceLivenessSession requests, the same session is returned. This token is employed to avoid unintentionally creating the same session multiple times.

Type: String

Length Constraints: Minimum length of 1. Maximum length of 64.

Pattern: ^[a-zA-Z0-9-_]+$

Required: No


The identifier for your AWS Key Management Service key (AWS KMS key). Used to encrypt audit images and reference images.

Type: String

Length Constraints: Minimum length of 1. Maximum length of 2048.

Pattern: ^[A-Za-z0-9][A-Za-z0-9:_/+=,@.-]{0,2048}$

Required: No


A session settings object. It contains settings for the operation to be performed. For Face Liveness, it accepts OutputConfig and AuditImagesLimit.

Type: CreateFaceLivenessSessionRequestSettings object

Required: No

Response Syntax

{ "SessionId": "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.


A unique 128-bit UUID identifying a Face Liveness session. A new sessionID must be used for every Face Liveness check. If a given sessionID is used for subsequent Face Liveness checks, the checks will fail. Additionally, a SessionId expires 3 minutes after it's sent, making all Liveness data associated with the session (e.g., sessionID, reference image, audit images, etc.) unavailable.

Type: String

Length Constraints: Fixed length of 36.

Pattern: [0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}


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


You are not authorized to perform the action.

HTTP Status Code: 400


Amazon Rekognition experienced a service issue. Try your call again.

HTTP Status Code: 500


Input parameter violated a constraint. Validate your parameter before calling the API operation again.

HTTP Status Code: 400


The number of requests exceeded your throughput limit. If you want to increase this limit, contact Amazon Rekognition.

HTTP Status Code: 400


Amazon Rekognition is temporarily unable to process the request. Try your call again.

HTTP Status Code: 500

See Also

For more information about using this API in one of the language-specific AWS SDKs, see the following: