books
HathiTrust
A large collaborative digital library of over 18 million digitized volumes drawn from research libraries. A keyless bibliographic interface returns catalogue records with deep links into the reader; public-domain volumes are readable while in-copyright full text is restricted to affiliated members. Reach for it to verify holdings and access scanned volumes, though its search interface can present a challenge page from some networks.
Why it’s useful & how it works
Full-text/content Data API was retired 17 Jul 2024; only the keyless Bibliographic API survives (works both ways for probes). User-facing search UI is CF-challenged → access downgraded to captcha to honestly describe the deep-link experience. Metadata + deep link; full text is login/affiliation-gated.
What’s inside
~18M+ volumes.
API access
https://catalog.hathitrust.org/api/volumes/brief/json/ <idtype>:<id>
Access
May require solving a captcha before it responds.