| topic_arn | string | no | no | The ARN of the target SNS topic. |
| message_group_id | string | yes | no | An optional group ID to set for messages. |
| message_deduplication_id | expression | yes | no | An optional deduplication ID to set for messages. |
| max_in_flight | int | yes | no | The maximum number of parallel message batches to have in flight at any given time. The value defaults to 64. |
| metadata | metadata | yes | no | Specify criteria for which metadata values are attached to objects as headers. |
| region | string | no | no | The AWS region to target. |
| endpoint | string | yes | no | Allows you to specify a custom endpoint for the AWS API. |
| credentials | credentials | no | no | Optional manual configuration of AWS credentials to use. More information can be found in the AWS Guide. |