removeBackground may not be set to false: AI Uncrop always has to be combined with background removal.
The API will later start enforcing this.
Additional Parameters
uncrop.seed
If you make several calls to the Image Editing API with the same image, you will notice that it will generate a different uncropped subject every time.
In order to reduce the randomness, you can set a fixed value for the seed that the API's random generator will use. The value of the argument uncrop.seed can be any positive integer.
If you provide a value for uncrop.seed, then the API should produce similar-looking subject uncroppings for the same image.