
Based on the Stanford Dogs Dataset.
Dogs API is a free Animals API that requires no API key, is served over HTTPS and supports CORS, so it can be called from the browser.
Dog CEO's Dog API. Over 20,000 images of dogs programmaticaly accessible by over 120 breeds. Image supplied by the Stanford Dogs Dataset.
Details from dog.ceo.

Unified API suite · now live
Geocode an address, validate an email, track a flight or pull stock data with one account, one dashboard and one API key.
The Dogs API is provided by Dog API (dog.ceo). Dog CEO's Dog API. Over 20,000 images of dogs programmaticaly accessible by over 120 breeds. Image supplied by the Stanford Dogs Dataset.
Yes. The Dogs API is listed in the Animals category of the public-apis directory, which only includes APIs that are free or have a free tier. Check its documentation for rate limits and paid plans.
No. The Dogs API requires no authentication, so you can start making requests without signing up.
Yes. The Dogs API supports CORS, so front-end JavaScript can call it directly.
Yes. The Dogs API is served over HTTPS, so it's safe to use in production.