Use Z-Image through Rivya Public API v1 with model id z-image, supported inputs, parameters, Files API rules, credits, and response examples.

Available via APIText input readyImage

API model id

z-image

Inputs

text

Files API

Not required for the minimal request

Base credits

Capability

Image

Billing

FIXED

Prompt limit

1000 characters

Request contract

Send the model id at the top level. Model-specific controls belong in params.

Key	Type	Required	Default	Description
model	string	Yes	z-image	Use the z-image API model id.
prompt	string	Yes	-	Maximum 1000 characters for this model.
params	object	No	-	Model-specific parameter object. Use the rows below for allowed keys.
client_request_id	string	No	-	Optional client-side id for tracing requests in your system.

Model parameters

Key	Type	Required	Default	Range	Options	Description
aspect_ratio	select	No	1:1	-	1:1, 4:3, 3:4, 16:9, 9:16	Aspect ratio

Minimal request

{
  "model": "z-image",
  "prompt": "A clean editorial product image on a soft studio background",
  "params": {
    "aspect_ratio": "1:1"
  }
}

Create response

The create endpoint returns a public task id. Poll the status endpoint until the task succeeds or fails.

{
  "id": "task_z_image_example",
  "status": "queued",
  "model": "z-image",
  "reserved_credits": 1,
  "final_credits": 0,
  "created_at": "2026-05-11T00:00:00.000Z",
  "updated_at": "2026-05-11T00:00:00.000Z",
  "result": null,
  "error": null
}

Common errors

validation_failed, insufficient_credits, idempotency_conflict, rate_limited, not_found