AdoptAPet vs Cat Facts

AdoptAPet's free Pet List API lets a registered shelter or rescue pull its own current adoptable-pet listings — name, photo, breed, and a link back to the pet's page — for display on its own website; it doesn't cover other shelters' animals or expose network-wide search. Access needs a per-shelter API key passed as a key query parameter to endpoints like api.adoptapet.com/search/pets_at_shelter, confirmed live by a real GET that returns a JSON invalid_key error rather than a redirect or outage, with a separate OPTIONS preflight and that same GET both echoing access-control-allow-origin: * back for a test Origin header. The official documentation page now sits behind a shelter-account login (a live probe returns 401 with a Basic-auth challenge, a change from when it was openly readable), but the API endpoint itself remains fully live and free, returning JSON or XML depending on the output parameter.

catfact.ninja is a free, keyless REST API built on Laravel that serves a curated database of cat trivia facts alongside a separate cat-breed dataset (coat, pattern, country of origin, and more). Its /fact endpoint returns one random fact, while /facts and /breeds paginate through the full ~166- and 98-page collections respectively. The API documents itself via a Swagger UI hosted at its own root and throttles unauthenticated requests to 100 per minute per IP.