Metropolitan Museum of Art vs Rijksmuseum

The Met's Collection API exposes all 502,000+ objects in its Open Access collection — the same data behind its own site — fully keyless and free, asking only that callers self-throttle to 80 requests per second. A live GET against the real gateway, collectionapi.metmuseum.org, returned genuine object data carrying Access-Control-Allow-Origin: *, correcting cors no -> yes while reconfirming auth None.

The Rijksmuseum has replaced its old key-gated REST collection API with a free, fully keyless Linked Open Data service: a Linked Art-based Search API at data.rijksmuseum.nl/search/collection and a Persistent Identifier Resolver at id.rijksmuseum.nl, both returning JSON-LD. A live GET against the real search endpoint returned 1,463 genuine matching results for a Rembrandt query with Access-Control-Allow-Origin: *, and its own docs explicitly state no API key is needed — correcting the stored url off its retired /object-metadata/api/ path (now a 404), auth API Key -> None, and cors unknown -> yes.