clientMetadata

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 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 request. In your function code, you can process the clientMetadata value to enhance your workflow for your specific needs.

To review the Lambda trigger types that Amazon Cognito invokes at runtime with API requests, see Connecting API actions to Lambda triggers in the Amazon Cognito Developer Guide.

The ClientMetadata value is passed as input to the functions for only the following triggers:

• Pre signup

• Pre authentication

• User migration

This request also invokes the functions for the following triggers, but doesn't pass ClientMetadata:

• Post authentication

• Custom message

• Pre token generation

• Create auth challenge

• Define auth challenge

• Custom email sender

• Custom SMS sender

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 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.