[jamesponddotco]

Hardcover and ISBNDB have a good amount of data, with Hardcover being excellent for getting good covers and genres.

I'm hoping Goodreads and Anna's Archive will help fill in the gaps, especially since Anna's Archive have gigantic database dumps available[1].

[1]: https://todo.sr.ht/~pagina394/librario/12

[culi]

You should also consider OpenLibrary and LibraryThing. Both of which have good coverage on WikiData which also aggregates identifiers.

In fact, now that I think about it, you could also contribute your work to WikiData. I don't see ISBNdb ids on WikiData so you could write a script to make those contributions. Then anyone else using WikiData for this sort of thing can benefit from your work

[jamesponddotco]

I haven’t created a ticket for OpenLibrary yet, but it’s on my mental todo list. I’ll create the ticket for multiple new extractors today.

I’d love to help improve other services. I plan on charging for Librario at some point, but I’ll offer a free version and offer free API keys for projects like Calibre and others.

At least that’s the plan.

[zozbot234]

ISBNid seems to use ISBN-13 for its unique identifier, which is just Property:P212 on Wikidata.