Use the command line and client libraries

The papertotal command lists receipts and categories, exports a year of receipts and processes files. Install it with npm from the link at papertotal.com/developers, and set PAPERTOTAL_API_KEY to a key of yours.

The client libraries are generated from the OpenAPI document and tested against the API, with a typed method for every call, paging, retries that wait as long as Retry-After says, and typed errors. They are not in package registries yet, so download one from the same page. Its README says how to add it to a project.