openlibrary — Book Metadata from Open Library

Query Open Library's 50M+ record catalog over its public HTTP API: search works and authors, walk the edition/work/author graph by ISBN or OLID, enumerate editions, and read community ratings. No API key exists; everything here is a keyless GET.

Setup

Nothing to authenticate: the public Open Library API requires no API key for reads. There is no token, no registration step, no lazy-auth dance.

# Optional etiquette: identified User-Agent gets ~3x rate budget (~3 req/s vs ~1)
export OL_EMAIL="you@example.com"