When I visit my local library, I open biblio.dcain.me to see which of my Goodreads titles are available for check-out.
An AWS Lambda function takes care of the catalog-querying logic. First, an authenticated request is made to the Goodreads API to retrieve a list of books I want to read. Then, a series of library catalog requests (exploiting undocumented API's) are executed in parallel. When these requests complete, the results are presented in simple interface for easy skimming.