HTTP Dog vs MeowFacts

http.dog serves a themed dog photo for most standard HTTP status codes (e.g. GET /200, /404, /451), following the same status-code-as-image idea as http.cat. A .json variant returns direct links to the same image in JPEG, WebP, AVIF, and JXL instead of the image itself. It's a static Cloudflare-fronted site with no server-side application logic, so there's no API key, authentication, or rate limit of any kind.

meowfacts is a free, keyless REST API that returns one or more random cat facts as JSON, with count and id query parameters for multiple or specific facts. A lang parameter serves community-translated fact sets in around 15 languages (English, Spanish, French, German, Korean, Russian, and others, by browser-style ISO 639 code). It's an open-source (GPL) side project hosted on a free Heroku dyno and documented via SwaggerHub, with no signup, key, or pricing tier.