Hey Tim!
As stated in our Security page, in the Data protection section:
Customer backups
Customers are free to comply with additional backup requirements beyond what Prismic provides by using the Export module (starting from the medium plan) or by querying their Repository API endpoint.
You can simply backup all of your content stored on your Prismic repository by querying all of the documents exposed by the API. Note that this will not fetch drafts, archived documents, or assets that are not linked to a document.
And to backup Custom types, the best practice is to keep a copy of the custom type in your codebase as it’s reflected there in the code. You can read more about that here:
If you have accidentally deleted a custom type, you can retrieve it: