AdoptAPet vs Dogs

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.

The Dog CEO API serves random and breed-filtered dog images sourced from the Stanford Dogs Dataset plus community submissions, returning a direct image URL as JSON rather than the binary file itself. A live call to its breed list returns 108 main breeds and 99 named sub-breeds (42 of the mains have sub-breeds), giving 207 callable breed image paths across 165 leaf-level breed collections, each queryable via dedicated endpoints (e.g. /breed/hound/images/random), and it needs no signup or API key. The project is open-source with no pricing tier of any kind; hosting is covered by on-site ads plus voluntary PayPal donations.