Use Gen 4 Image with Comfy Router

Call runway/gen4_image through Comfy Router: endpoint, request shape and the response Router returns.

API Reference for runway/gen4_image, served by Comfy Router from Runway.

Quick start

Create a key in your Comfy workspace and export it as COMFY_API_KEY. The Python and TypeScript snippets use the Comfy SDKs (pip install comfy-sdk, npm install @comfyorg/sdk); the cURL snippet is the same call over raw HTTP.

Model ID: runway/gen4_image

Endpoint: POST https://api.comfy.org/v2/models/runway/gen4_image

Python

from comfy_sdk import Comfy

# Reads COMFY_API_KEY from the environment.
# The SDK automatically creates an idempotency key and reuses it for automatic retries.
with Comfy() as client:
    result = client.models.run(
        "runway/gen4_image",
        {
            "promptText": "a red circle",
            "ratio": "1024:1024",
        },
    )

print(result)

Schema

Input

model · string

Model to use for generation. On the Comfy Router route POST /v2/models/runway/{model} this field is supplied from the path and MUST NOT be sent; on the v1 POST /proxy/runway/text_to_image route it is required and constrained to gen4_image.

promptText · string · required

Text prompt for the image generation

ratio · string · required

Possible values: 1920:1080, 1080:1920, 1024:1024, 1360:768, 1080:1080, 1168:880, 1440:1080, 1080:1440, 1808:768, 2112:912

referenceImages · object[]

Array of reference images to guide the generation

referenceImages[].uri · string · required

A HTTPS URL or data URI containing an encoded image

Generated from the schema Router serves at GET /v2/models/runway/gen4_image/openapi.json, the same document it validates a call against before the request reaches the provider.

Output

createdAt · string (date-time) · required

Task creation timestamp

Format: date-time

id · string · required

Task ID

output · string[]

The finished generation’s asset URLs — for runway/gen4_image each element is an IMAGE URL. Present once the task terminates successfully; this list IS the result.

progress · number

Float value between 0 and 1 representing the progress of the task. Only available if status is RUNNING.

Range: 0 to 1

Format: float

status · string · required

Possible statuses for a Runway task.

Possible values: SUCCEEDED, RUNNING, FAILED, PENDING, CANCELLED, THROTTLED

Examples

Input

{
  "promptText": "a red circle",
  "ratio": "1024:1024"
}

Output

{
  "createdAt": "2027-01-01T00:00:00Z",
  "id": "5f7c1b28-9a03-4e61-8d2f-1b2c3d4e5f60",
  "output": [
    "https://example.invalid/runway/gen4_image/generated.png"
  ],
  "status": "SUCCEEDED"
}

Before you ship

The SDKs create an Idempotency-Key and reuse it for automatic retries. For manual retries, reuse the original key. Router can hold the connection for up to 10 minutes.

When a request fails, Router sends an X-Comfy-Error-Type response header explaining why. A 422 means Router rejected the input before calling the provider. Download generated assets promptly because result URLs can expire.

Headers

Authentication, idempotency, request IDs, error buckets, retry pacing, spend limits.

Using the Router API

Model discovery, validation errors, retries, and billing.

Limitations

What Router does not do today, and what to use instead.