We call ours "bombing-range"

We maintain an internal service that hosts two endpoints; /random-cat-picture (random >512KB image + UUID + text timestamp to evade caching) and /api/v1/generic.json which allows developers and platform folks to test out new ideas from commit to deploy behind a load balancer in an end-to-end fashion, it has saved countless headaches over the years.

a display of great wisdom, nice