identityValidationExpression

A validation expression for the incoming identity token. For `TOKEN` authorizers, this value is a regular expression. For `COGNITO_USER_POOLS` authorizers, API Gateway will match the `aud` field of the incoming token from the client against the specified regular expression. It will invoke the authorizer's Lambda function when there is a match. Otherwise, it will return a 401 Unauthorized response without calling the Lambda function. The validation expression does not apply to the `REQUEST` authorizer.