British National Bibliography vs Open Library

The British National Bibliography is the British Library's record of everything published in the UK and Ireland since 1950, now published as BIBFRAME/RDA linked open data through the multi-national "Share Family" platform. Its original bnb.data.bl.uk endpoint has been offline since the Library's October 2023 cyber-attack destroyed its digital infrastructure; the catalog has since resurfaced on a beta institutional search portal, per the Library's own service-status and metadata-services pages.

Open Library, an Internet Archive project, exposes its book catalog for search, work/edition/author lookups by identifier, subjects, and public reading lists, returned as JSON, YAML, or RDF/XML, with a separate Covers API serving cover art by ISBN or Open Library ID. No API key is required, though sending a descriptive User-Agent and contact email triples the default 1-request-per-second anonymous rate limit. Bulk access is deliberately kept off the live API — the project publishes free monthly data dumps for that instead.