POST gen4/video

Create a video using Runway Gen-4 Aleph (video-to-video)

August 4, 2025

Request Headers
Request Body
Responses
Model
Examples
Try It

Gen-4 Aleph is Runway’s video-to-video generation model that allows you to transform an input video using text prompts and optional image conditioning.

Please be aware that Runway’s moderation system analyzes your video and text prompts and may fail task with moderation message if the prompt is determined to be offensive. Runway monitors the rate and the number of moderated tasks, which may result in your account being suspended when the internal threshold is exceeded.

https://api.useapi.net/v1/runwayml/gen4/video

Request Headers

Authorization: Bearer {API token}
Content-Type: application/json
# Alternatively you can use multipart/form-data
# Content-Type: multipart/form-data

API token is required, see Setup useapi.net for details.

Request Body

{
    "video_assetId": "Required assetId of video asset",
    "image_assetId": "Optional assetId of image asset",
    "text_prompt": "Required text prompt describing the transformation",
    "seed": 12345678,
    "exploreMode": true,    
    "replyUrl": "Place your call back URL here",
    "replyRef": "Place your reference id here",
    "maxJobs": 5
}

video_assetId is required. Specify the video assetId you want to transform. The video must have duration, width, and height metadata. Use GET /assets/?mediaType=video to see the list of video assets. To upload a new video asset use POST /assets.
image_assetId is optional. Specify an image assetId to use as additional conditioning for the video transformation. Use GET /assets/?mediaType=image to see the list of image assets.
text_prompt is required. Describe the desired transformation or style for the video. Creating with Aleph.
Maximum length: 1000 characters.
seed is optional. Random seed for reproducible results.
Valid range 1…4294967294.
exploreMode is optional. Set to true if you have a Runway Unlimited plan and wish to execute relaxed generation. You are not charged credits for Explore mode generations.
replyUrl is optional, if not provided value from useapi.net account will be used.
Place here your callback URL. API will call the provided replyUrl once Runway task completed or failed.
Maximum length 1024 characters.
We recommend using sites like webhook.site to test callback URL functionality.
replyRef is optional, place here your reference id which will be stored and returned along with this Runway task response / result.
Maximum length 1024 characters.
maxJobs is optional, if not provided value for referenced by video assetId account will be used.
Valid range: 1…10.
Runway has dynamic query capacity and guarantees that, for a given account, at least one job will run — often two, and very rarely, three. If you have a single account linked, keep adding new jobs until you receive a 429 response. Once you get a 429, wait for xx seconds or until at least one job completes, then try again. If you need to run more jobs in parallel, simply add more Runway accounts.

Responses

200 OK

Use returned taskId to retrieve task status and results using GET /tasks/taskId. The generated video url can be found in the artifacts array of the task with the status SUCCEEDED.

If you specify the optional parameter replyUrl the API will call the provided replyUrl with task progress updates until the task is complete or fails.

{
  "task": {
    "taskId": "user:user_id-runwayml:account_email-task:task_uuid",
    "id": "<uuid>",
    "name": "<name>",
    "image": null,
    "createdAt": "2024-08-01T01:02:03.456Z",
    "updatedAt": "2024-08-01T01:02:03.456Z",
    "taskType": "gen4_aleph",
    "options": {
        "name": "<name>",
        "text_prompt": "<your text prompt>",
        "seed": 12345789,
        "exploreMode": true,
        "watermark": false,
        "seconds": 5,
        "width": 1280,
        "height": 720,
        "video": "<input video url>",
        "images": ["<optional image url>"],
        "imageAssetIds": ["<optional image asset id>"],
        "assetGroupId": "<asset group id>",
        "recordingEnabled": true
    },
    "status": "PENDING",
    "error": null,
    "progressText": null,
    "progressRatio": null,
    "estimatedTimeToStartSeconds": 0,
    "artifacts": [],
    "sharedAsset": null,
    "replyUrl": "https://webhook.site/abc",
    "replyRef": "<your optional reference id>",
    "code": 200
  }
}

400 Bad Request

{
  "error": "<Error message>",
  "code": 400
}

401 Unauthorized

{
  "error": "Unauthorized",
  "code": 401
}

404 Not Found

{
    "error": "Unable to retrieve assetId <uuid> (Not found.)",
    "code": 404
}

412 Insufficient credits

You do not have enough credits to run this task.

{
    "error": "You do not have enough credits to run this task."
}

429 Too Many Requests

Wait in a loop for at least 10..30 seconds and retry again.

There are two possible cases for API response 429:

API query is full and can not accept new gen4/video requests. Size of query defined by maxJobs optional parameter.

{
    "error": "Account <Runway account email> is busy executing <Account maxJobs> tasks",
    "runningTasks": {
        "<Runway account email>": [
            {
                "email": "<Runway account email>",
                "taskId": "user:user_id-runwayml:account_email-task:task_#1_uuid",
                "id": "<uuid>",
                "replyUrl": "<replyUrl if provided>",
                "replyRef": "<replyRef if provided>"
            },
            {
                "email": "<Runway account email>",
                "taskId": "user:user_id-runwayml:account_email-task:task_#N_uuid",
                "id": "<uuid>",
                "replyUrl": "<replyUrl if provided>",
                "replyRef": "<replyRef if provided>"
            }
        ]
    },
    "code": 429
}

The API received an HTTP response status 429 from Runway. Runway has dynamic query management and may limit the number of simultaneously executed tasks based on internal service load and policies.

{
    "error": "You have too many tasks running or pending. Please wait for some of them to finish before starting more."
}

Model

{ // TypeScript, all fields are optional
  task: {
    taskId: string,
    id: string,
    name: string,
    image: string,
    createdAt: string,
    updatedAt: string,
    taskType: string,
    options: {
          name: string,
          text_prompt: string,
          seed: number,
          exploreMode: boolean,
          watermark: boolean,
          seconds: number,
          width: number,
          height: number,
          video: string,
          images: string[],
          imageAssetIds: string[],
          assetGroupId: string,
          recordingEnabled: boolean
    },
    status: string,
    progressText: string,
    progressRatio: number,
    estimatedTimeToStartSeconds: number,
    artifacts: any[],
    sharedAsset: any,
    error: {
      errorMessage: string,
      reason: string,
      message: string,
      moderation_category: string,
      tally_asimov: boolean
    },  
    code: number,
    replyUrl: string,
    replyRef: string
  }
}

Examples

curl -H "Accept: application/json" \
     -H "Content-Type: application/json" \
     -H "Authorization: Bearer …" \
     -X POST "https://api.useapi.net/v1/runwayml/gen4/video" \
     -d '{"video_assetId": "…", "text_prompt": "transform this video into a cinematic scene"}'

const video_assetId = "assetId of video asset";      
const text_prompt = "transform this video into a cinematic scene";      
const apiUrl = `https://api.useapi.net/v1/runwayml/gen4/video`; 
const token = "API token";
const data = { 
  method: 'POST',
  headers: {
    'Authorization': `Bearer ${token}`,
    'Content-Type': 'application/json' }
};
data.body = JSON.stringify({ 
  video_assetId, text_prompt
});
const response = await fetch(apiUrl, data);
const result = await response.json();
console.log("response", {response, result});

import requests
video_assetId = "assetId of video asset"      
text_prompt = "transform this video into a cinematic scene"      
apiUrl = f"https://api.useapi.net/v1/runwayml/gen4/video" 
token = "API token"
headers = {
    "Content-Type": "application/json", 
    "Authorization" : f"Bearer {token}"
}
body = {
    "video_assetId": f"{video_assetId}",
    "text_prompt": f"{text_prompt}"
}
response = requests.post(apiUrl, headers=headers, json=body)
print(response, response.json())