> ## Documentation Index
> Fetch the complete documentation index at: https://apixo.ai/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# Runway Gen4 Video Turbo

> Runway Gen4 image-to-video API with prompt guidance, one source image, and per-second billing

## Overview

Runway Gen4 Video Turbo animates a source image into a short video using a text prompt. Use it when you already have an image and want controlled motion, camera direction, or atmosphere.

| Capability    | Value                                                   |
| ------------- | ------------------------------------------------------- |
| Model ID      | `runway-gen4-video-turbo`                               |
| Mode          | `image-to-video`                                        |
| Prompt        | Required non-empty string                               |
| Source image  | Exactly 1 public image URL                              |
| Duration      | Integer or integer string from `5` through `10` seconds |
| Aspect ratios | `16:9`, `4:3`, `1:1`, `3:4`, `9:16`                     |
| Billing       | Per second                                              |

## Endpoint and authentication

Base URL:

```text theme={null}
https://api.apixo.ai/api/v1
```

| Method | Endpoint                                              | Purpose                               |
| ------ | ----------------------------------------------------- | ------------------------------------- |
| `POST` | `/generateTask/runway-gen4-video-turbo`               | Submit a video generation task        |
| `GET`  | `/statusTask/runway-gen4-video-turbo?taskId={taskId}` | Poll task status and retrieve results |

All requests require your APIXO API key:

```http theme={null}
Authorization: Bearer YOUR_API_KEY
```

Submit requests also require:

```http theme={null}
Content-Type: application/json
```

## Copy-paste async quickstart

```bash theme={null}
curl -X POST "https://api.apixo.ai/api/v1/generateTask/runway-gen4-video-turbo" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "request_type": "async",
    "input": {
      "prompt": "The subject walks forward through soft morning fog, cinematic camera movement",
      "image_urls": [
        "https://example.com/source-image.png"
      ],
      "duration": 5,
      "aspect_ratio": "16:9"
    }
  }'
```

Successful response:

```json theme={null}
{
  "code": 200,
  "message": "success",
  "data": {
    "taskId": "task_12345678"
  }
}
```

## Poll for result

```bash theme={null}
curl -X GET "https://api.apixo.ai/api/v1/statusTask/runway-gen4-video-turbo?taskId=task_12345678" \
  -H "Authorization: Bearer YOUR_API_KEY"
```

Success response:

```json theme={null}
{
  "code": 200,
  "message": "success",
  "data": {
    "taskId": "task_12345678",
    "state": "success",
    "resultJson": "{\"resultUrls\":[\"https://file.apixo.ai/runway-gen4-video-turbo.mp4\"]}",
    "createTime": 1782980000000,
    "completeTime": 1782980060000,
    "costTime": 60000
  }
}
```

## Request body

### Image-to-video

```json theme={null}
{
  "request_type": "async",
  "input": {
    "mode": "image-to-video",
    "prompt": "He lifts the noodles with chopsticks as steam curls around his face",
    "image_urls": [
      "https://example.com/source-image.png"
    ],
    "duration": "10",
    "aspect_ratio": "4:3"
  }
}
```

The `mode` field is optional on this endpoint. If omitted, APIXO uses `image-to-video`.

## Parameters

<ParamField body="request_type" type="string" default="async">
  Result delivery mode. Use `async` for polling with `statusTask`, or `callback` for webhook delivery.
</ParamField>

<ParamField body="callback_url" type="string">
  Required when `request_type` is `callback`. Must be a public HTTPS URL that can receive the final task payload. See [Webhooks](/api-reference/webhooks).
</ParamField>

<ParamField body="input" type="object" required>
  Runway Gen4 Video Turbo input parameters.

  <Expandable title="properties">
    <ParamField body="mode" type="string" default="image-to-video">
      Optional generation mode. This endpoint supports `image-to-video` only.
    </ParamField>

    <ParamField body="prompt" type="string" required>
      Text prompt describing the desired motion, camera movement, and scene changes. The prompt must be a non-empty string after trimming whitespace.
    </ParamField>

    <ParamField body="image_urls" type="string[]" required>
      Source image URLs. Provide exactly 1 public, directly accessible image URL.
    </ParamField>

    <ParamField body="duration" type="integer | string" default="5">
      Output duration in seconds. Accepts a JSON integer or integer string from `5` through `10`. Decimal values are not valid.
    </ParamField>

    <ParamField body="aspect_ratio" type="string">
      Optional output aspect ratio. Supported values: `16:9`, `4:3`, `1:1`, `3:4`, `9:16`.
    </ParamField>
  </Expandable>
</ParamField>

## Response format

### Submit task response

`POST /generateTask/runway-gen4-video-turbo` returns a task ID when the task is accepted:

<ResponseField name="code" type="integer">
  API status code. `200` means the task was accepted.
</ResponseField>

<ResponseField name="message" type="string">
  Human-readable status message.
</ResponseField>

<ResponseField name="data.taskId" type="string">
  Unique task identifier used with the status endpoint.
</ResponseField>

### Status response fields

<ResponseField name="taskId" type="string">
  Unique task identifier.
</ResponseField>

<ResponseField name="state" type="string">
  Current task state: `pending`, `processing`, `success`, or `failed`.
</ResponseField>

<ResponseField name="resultJson" type="string">
  JSON string containing generated video URLs in `resultUrls`. Present when `state` is `success`.
</ResponseField>

<ResponseField name="failCode" type="string">
  Machine-readable failure code. Present when `state` is `failed`.
</ResponseField>

<ResponseField name="failMsg" type="string">
  Human-readable failure message. Present when `state` is `failed`.
</ResponseField>

<ResponseField name="createTime" type="integer">
  Task creation timestamp in Unix milliseconds.
</ResponseField>

<ResponseField name="completeTime" type="integer">
  Task completion timestamp in Unix milliseconds. Present after completion.
</ResponseField>

<ResponseField name="costTime" type="integer">
  Processing duration in milliseconds when available.
</ResponseField>

## Webhook callback mode

Use callback mode when your backend should receive the final result automatically instead of polling.

```bash theme={null}
curl -X POST "https://api.apixo.ai/api/v1/generateTask/runway-gen4-video-turbo" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "request_type": "callback",
    "callback_url": "https://your-server.com/webhooks/apixo",
    "input": {
      "prompt": "Slow dolly-in, soft cinematic motion, rain on the window",
      "image_urls": [
        "https://example.com/source-image.png"
      ],
      "duration": 5,
      "aspect_ratio": "16:9"
    }
  }'
```

See [Webhooks](/api-reference/webhooks) for delivery requirements and retry behavior.

## Billing

Runway Gen4 Video Turbo is billed per output second.

| Unit       | APIXO price      |
| ---------- | ---------------- |
| Per second | `$0.01 / second` |

Formula:

```text theme={null}
total cost = duration * 0.01
```

## Latency and polling

Actual latency may vary by duration, prompt complexity, source image accessibility, and current queue load.

| Duration | Typical generation time | Recommended first poll  | Poll interval |
| -------- | ----------------------- | ----------------------- | ------------- |
| `5s`     | 45s-75s                 | 45s after task creation | 5s            |
| `10s`    | 75s-120s                | 60s after task creation | 5s            |

<Tip>
  For production video workloads, use callback mode to avoid frequent polling while generation is still running.
</Tip>

## Validation notes

| Parameter            | Backend behavior                                                                                                  |
| -------------------- | ----------------------------------------------------------------------------------------------------------------- |
| `input.mode`         | Optional. If provided, it must be `image-to-video`. If omitted, APIXO uses `image-to-video`.                      |
| `input.prompt`       | Required string. Must not be empty after trimming whitespace.                                                     |
| `input.image_urls`   | Required. Must be an array with exactly 1 non-empty string URL.                                                   |
| `input.duration`     | Optional. Defaults to `5`. Accepts a JSON integer or integer string from `5` through `10`; decimals are rejected. |
| `input.aspect_ratio` | Optional. If provided, must be one of `16:9`, `4:3`, `1:1`, `3:4`, `9:16`.                                        |

## Errors and troubleshooting

| Code  | Meaning                                                                                                       | What to do                                       |
| ----- | ------------------------------------------------------------------------------------------------------------- | ------------------------------------------------ |
| `400` | Invalid request body, missing source image, invalid duration, invalid aspect ratio, or inaccessible image URL | Fix the request before retrying                  |
| `401` | Missing or invalid API key                                                                                    | Check the `Authorization` header                 |
| `402` | Insufficient balance or quota                                                                                 | Add balance or switch account/key                |
| `403` | Key or route cannot access the model                                                                          | Check permissions and route strategy             |
| `429` | Rate limit or concurrency limit reached                                                                       | Retry with exponential backoff                   |
| `500` | Server error or unknown generation failure                                                                    | Retry with backoff                               |
| `502` | Generation service or network error                                                                           | Retry with backoff                               |
| `504` | Generation timeout                                                                                            | Retry or use callback mode for long-running jobs |

See [Error Codes](/api-reference/errors) for the full error reference.

## Related links

* [Generation API Overview](/models)
* [Generate Task](/api-reference/generate-task)
* [Status Task](/api-reference/status-task)
* [Webhooks](/api-reference/webhooks)
* [Error Codes](/api-reference/errors)
* [Parameter Specification](/api-reference/parameters)
* [Routing Strategies](/concepts/routing-strategies)
* [Pricing](https://apixo.ai/pricing)