CLIO Library Catalog Open Data
Columbia University Libraries publishes its full catalogue — bibliographic and holdings records from the integrated library system behind CLIO — as gzipped MARCXML bulk extracts under a CC0 1.0 Public Domain Dedication, refreshed monthly, alongside a deletes file. 108 files were present in the extract directory at probe time, served from an open Apache directory index with no credential and no rate limit. Covers books, serials, music, video and manuscripts; excludes Law Library and ReCAP partner records. There is no manifest, no checksum, no change feed and no harvesting protocol — a consumer diffs the directory listing.