> For the complete documentation index, see [llms.txt](https://docs.wellcomecollection.org/storage-service/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.wellcomecollection.org/storage-service/how-to-advanced-usage/get-notifications-of-stored-bags.md).

# Getting notifications of newly stored bags

When the storage service successfully stores a bag, it sends a notification to an SNS topic. You can subscribe to this topic to react to updates, e.g. if you want to trigger some downstream processing.

This will be a topic whose name ends `registered_bag_notifications`.

This topic will receive JSON messages that look similar to the following:

```json
{
  "space": "digitised",
  "externalIdentifier": "b20278512",
  "version": "v1",
  "type": "RegisteredBagNotification"
}
```

Any bag described in this topic should be retrievable through the bags API.