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

# Text to Video

> Source: https://kling.ai/document-api/api/video/4-0-flash/text-to-video
> Locale: en
> Current Tab: Text to Video
> Sibling Tabs: Text to Video / Image to Video / Omni Video Generation / Element Management
> This content is optimized for LLMs. In-page tabs are expanded and UI-only controls are omitted.

---

## Create Task

### API Overview

- Method: `POST`
- Path: `/text-to-video/kling-4.0-flash`
- Auth: `Authorization: Bearer <API_KEY>`
- Content-Type: `application/json`

### Headers

| Field | Type | Required | Default | Enum | Description |
|---|---|---:|---|---|---|
| `Content-Type` | string | Yes | `application/json` | - | Data Exchange Format |
| `Authorization` | string | Yes | - | - | Authentication information, refer to API authentication |

### Request Body

| Field Path | Type | Required | Default | Enum | Description |
|---|---|---:|---|---|---|
| `prompt` | string | Yes | - | - | The prompt can include positive and negative descriptions |
| `settings` | object | No | - | - | Output configuration-related parameters, such as resolution, duration, etc |
| `settings.resolution` | string | No | `720p` | `720p` | The resolution of the generated video |
| `settings.aspect_ratio` | string | No | `16:9` | `21:9`, `16:9`, `9:16`, `1:1` | The aspect ratio (width:height) of the generated video frames |
| `settings.duration` | int | No | - | `3`, `4`, `5`, `6`, `7`, `8`, `9`, `10`, `11`, `12`, `13`, `14`, `15`, `16`, `17`, `18`, `19`, `20` | Target duration of the generated video, in seconds. Integer values are supported. |
| `options` | object | No | - | - | General configurations, such as callback address, whether to include watermark, etc |
| `options.callback_url` | string | No | - | - | Callback notification URL for task result |
| `options.external_task_id` | string | No | - | - | Customized Task ID |
| `options.watermark_info` | object | No | - | - | Whether to generate watermarked results simultaneously |
| `options.watermark_info.enabled` | boolean | No | `false` | - | true: generate watermarked result; false: do not generate |

#### Request Body Field Notes

- `prompt`: English-only input supports up to 26,000 characters, and non-English-only input supports up to 11,000 characters. Mixed input must satisfy E / 26000 + N / 11000 <= 1, where E is the number of English characters and N is the number of non-English characters.
- `prompt`: > **The Kling 4.0 Flash Text-to-Video endpoint generates videos from prompts that describe scene content, character actions, camera movement, event sequences, and visual style.**
  >
  > 
  > 1. **Define the scene.** Describe the characters, setting, visual style, and lighting. For example: “A man in a white shirt walks along a beach at sunset, in a realistic cinematic style.”
  >
  > 
  > 2. **Describe actions and camera movement.** Specify how characters or objects move, how the camera follows them, and the order of events. For a sequence with multiple stages, describe each stage in chronological order. For more details, see the [Kling 4.0 & Kling 4.0 Flash User Guide](https://kling.ai/document-api/api/usage-guide/kling-4-0).
  >
  > 
  > 3. **This endpoint generates videos from text prompts. To provide reference images, videos, or elements, use the Omni Reference Generation endpoint.**
- `settings.resolution`: 720p: output video with a resolution of 720P
- `settings.duration`: When this parameter is set, its value takes precedence over any duration requested in the prompt.
- `settings.duration`: When this parameter is omitted, the model uses an explicit duration identified in the prompt. For example, "Generate a 15-second video" sets the target duration to 15 seconds.
- `settings.duration`: When this parameter is omitted and no explicit duration is identified in the prompt, the default is 10 seconds.
- `settings.duration`: The final target duration is used to bill the output video. It is returned as usage.output_duration in the task query response and as output_duration in deduction details. Use output_duration when calculating the cost, and apply the corresponding [billing rules](https://kling.ai/document-api/pricing/base/video).
- `options.callback_url`: If configured, the server will actively notify when the task status changes
- `options.callback_url`: For specific message schema, see [Callback Protocol](https://kling.ai/document-api/api/get-started/callbacks)
- `options.external_task_id`: Will not overwrite the system-generated task ID, but can be used for task queries
- `options.external_task_id`: Must be unique within a single user account
- `options.watermark_info`: Defined through the enabled parameter:
  ```json
  "watermark_info": {
    "enabled": false // true: generate watermarked result; false: do not generate; default: false
  }
  ```
- `options.watermark_info`: Custom watermarks are not currently supported

### Request Example

```bash
curl --location 'https://api-singapore.klingai.com/text-to-video/kling-4.0-flash' \
  --header 'Content-Type: application/json' \
  --header "Authorization: Bearer ${KLING_API_KEY}" \
  --data '{
    "prompt": "A girl sat on the train, looking out the window with a melancholic expression, her head swaying with the train.",
    "settings": {
      "duration": 16,
      "resolution": "720p",
      "aspect_ratio": "9:16"
    },
    "options": {
      "callback_url": "https://xxx/callback",
      "external_task_id": "",
      "watermark_info": {
        "enabled": false
      }
    }
  }'
```

### Response Example

```json
{
  "code": 0, // Error code. See Error Codes for details
  "message": "string", // Error information
  "request_id": "string", // Request ID, generated by the system
  "data": {
    "id": "string", // The task ID generated by the system
    "status": "string", // Task status, Enum values: submitted, processing, succeeded, failed
    "create_time": 1781080778802, // Task creation time, Unix timestamp, unit ms
    "update_time": 1781080794151, // Task update time, Unix timestamp, unit ms
    "external_id": "string" // The custom task ID for this task (if any)
  }
}
```

---

## Query Task (By task ID)

### API Overview

- Method: `GET`
- Path: `/tasks`
- Auth: `Authorization: Bearer <API_KEY>`
- Content-Type: `application/json`

### Description

> Note: The API currently supports querying async tasks only

### Headers

| Field | Type | Required | Default | Enum | Description |
|---|---|---:|---|---|---|
| `Content-Type` | string | Yes | `application/json` | - | Data Exchange Format |
| `Authorization` | string | Yes | - | - | Authentication information, refer to API authentication |

### Query Params

| Field | Type | Required | Default | Enum | Description |
|---|---|---:|---|---|---|
| `task_ids` | string | No | - | - | The task ID defined by the system that needs to be queried |
| `external_task_ids` | string | No | - | - | The custom task ID that needs to be queried |

#### Query Params Field Notes

- `task_ids`: Query parameter; provide the value in the URL query string
- `task_ids`: When querying a task, you can choose between two query methods: task_ids and external_task_ids, but you cannot use them simultaneously
- `task_ids`: Support batch queries, separated by ","
- `external_task_ids`: Query parameter; provide the value in the URL query string
- `external_task_ids`: When querying a task, you can choose between two query methods: task_ids and external_task_ids, but you cannot use them simultaneously
- `external_task_ids`: Support batch queries, separated by ","

### Request Example

```bash
curl --location 'https://api-singapore.klingai.com/tasks?task_ids=123' \
  --header 'Content-Type: application/json' \
  --header "Authorization: Bearer ${KLING_API_KEY}"
```

```bash
curl --location 'https://api-singapore.klingai.com/tasks?external_task_ids=123' \
  --header 'Content-Type: application/json' \
  --header "Authorization: Bearer ${KLING_API_KEY}"
```

### Response Example

```json
{
  "code": 0, // Error code. See Error Codes for details
  "message": "string", // Error information
  "request_id": "string", // Request ID, generated by the system, is used to track requests and troubleshoot problems
  "data": [
    {
      "id": "893605946402811985", // The task ID being queried
      "status": "string", // Task status, Enum values: submitted, processing, succeeded, failed
      "message": "string", // Task status information, displaying the failure reason when the task fails (such as triggering the content risk control of the platform, etc.)
      "create_time": 1781080778802, // Task creation time, Unix timestamp, unit ms
      "update_time": 1781080794151, // Task update time, Unix timestamp, unit ms
      "external_id": "string", // The custom task ID for this task (if any)
      "outputs": [
        {
          "type": "video", // When the generated result is "video", the return value and related fields vary by content type. Enum values: image, video, audio, element, voice
          "id": "string", // Video ID, generated by the system
          "url": "string", // Generated result URL with hotlink protection. (Generated results are retained for 30 days; save them promptly.)
          "watermark_url": "string", // URL for generating result with watermark, hotlink protection format
          "duration": "string" // The actual duration of the generated video file, in seconds. For the output video duration used for billing, see usage.output_duration.
        },
        {
          "type": "image", // When the generated result is "image", the return value and related fields vary by content type. Enum values: image, video, audio, element, voice
          "url": "string", // Generated result URL with hotlink protection. (Generated results are retained for 30 days; save them promptly.)
          "watermark_url": "string", // Image download URL with watermark, protected URL
          "group_id": "string" // Only appears when generating grouped images, used to mark grouping relationships
        },
        {
          "type": "audio", // When the generated result is "audio", the return value and related fields vary by content type. Enum values: image, video, audio, element, voice
          "id": "string", // Audio ID, generated by the system
          "mp3_url": "string", // Generated MP3 URL with hotlink protection. (Generated results are retained for 30 days; save them promptly.)
          "wav_url": "string", // Generated WAV URL with hotlink protection. (Generated results are retained for 30 days; save them promptly.)
          "mp3_duration": "string", // The duration of the generated MP3 format audio, in seconds
          "wav_duration": "string" // The duration of the generated WAV format audio, in seconds
        },
        {
          "type": "voice", // When the generated result is "voice", the return value and related fields vary by content type. Enum values: image, video, audio, element, voice
          "id": "string", // Voice ID, generated by the system
          "name": "string", // Voice name
          "url": "string", // Material download link
          "owned_by": "string", // Voice source, kling is the official voice library, and the number is the creator ID
          "status": "succeeded" // Voice status. Enum values: succeeded, deleted
        },
        {
          "type": "element", // When the generated result is "element", the return value and related fields vary by content type. Enum values: image, video, audio, element, voice
          "id": "string", // Element ID, generated by the system
          "name": "string", // Element name
          "description": "string", // Element description
          "element_type": "string", // Element type, divided into video character element and multi-image element, enumeration values are: video_character_elements and multi_image_elements
          "references": [ // Related materials of element
            {
              "type": "image", // When returning 'image' materials, the enumeration values for each content type are: image, video, voice
              "role": "string", // Image reference material attributes are divided into frontal reference images and other reference images, with enumeration values of frontal and reference, respectively
              "url": "string" // Material download link
            },
            {
              "type": "video", // When returning "video" materials, the enumeration values for each content type are: image, video, voice
              "role": "refer", // Video reference material attribute, fixed value: refer
              "url": "string" // Material download link
            },
            {
              "type": "voice", // When "voice" material is returned, enumeration values of each content type: image, video, voice
              "role": "refer", // Voice reference material attribute, fixed value: refer
              "url": "string", // Material download link
              "id": "string", // Voice ID
              "name": "string", // Voice name
              "owned_by": "string" // Voice source. kling means official voice library; numbers are creator IDs
            }
          ],
          "owned_by": "string", // Element source. kling means the official Element library; numbers are creator IDs
          "status": "string", // Element status. Enum values: succeeded, deleted
          "tags": [ // Element label related information
            {
              "id": 1, // Tag ID
              "name": "string", // Tag name
              "description": "string" // Tag description
            }
          ]
        }
      ],
      "usage": { // Usage: returned only after the task ends and usage is available; otherwise omitted. Available only for Kling 4.0 and Kling 4.0 Flash tasks.
        "input_duration": "8.03", // The total input video duration, including feature_video, base_video, and video character elements, returned as a string with two decimal places in seconds. Available only for Kling 4.0 and Kling 4.0 Flash tasks with video input. The duration is measured after system normalization, so it may differ slightly from the duration of the original video files.
        "output_duration": "5" // The output video duration used for billing, in seconds. Uses the duration specified in settings.duration when provided; otherwise, uses the generation duration specified in the prompt. If neither specifies a duration, the duration of base_video is rounded to the nearest whole second. If no base_video is provided, the default is 10 seconds.
      },
      "billing": [ // When task consumes balances from multiple cash types, the system will return multiple records.
        {
          "charge_type": "string", // Consumption account type: If the consumption is of balance, the parameter value is "cash"; if it is of resource package, the parameter value is "unit"
          "cash_type": "string", // Balance type. Only applicable when charge_type=cash. If the consumption is the official quota, the parameter value is balance. If the consumption is the test quota, the parameter value is test_balance. If the consumption is the reward quota, the parameter value is reward_balance.
          "amount": "string", // Deduction amount; In the balance deduction situation (charge_type=cash), it represents the discount price deducted from the balance, and in the resource package deduction situation (charge_type=unit), it represents the deduction amount of units; decimal system
          "currency": "string", // Consumption unit, which only exists in the consumption balance scenario (charge_type=cash), with a fixed parameter value of CNY/USD
          "package_type": "string", // Consumable resource bundle type, which only exists in the consumable resource bundle scenario (charge_type=unit), with fixed enumeration values: video, image, audio
          "list_price": "string" // Balance deduction list price only exists in the consumption limit scenario (charge_type=cash)
        }
      ]
    }
  ]
}
```

---

## Query Task (By Cursor)

### API Overview

- Method: `POST`
- Path: `/tasks`
- Auth: `Authorization: Bearer <API_KEY>`
- Content-Type: `application/json`

### Description

> Note: The API currently supports querying async tasks only

### Headers

| Field | Type | Required | Default | Enum | Description |
|---|---|---:|---|---|---|
| `Content-Type` | string | Yes | `application/json` | - | Data Exchange Format |
| `Authorization` | string | Yes | - | - | Authentication information, refer to API authentication |

### Request Body

| Field Path | Type | Required | Default | Enum | Description |
|---|---|---:|---|---|---|
| `start_time` | string | No | `end_time - 30 days` | - | Start time for task creation filtering |
| `end_time` | string | No | `current time` | - | End time for task creation filtering |
| `cursor` | string | No | - | - | Continuation cursor, i.e. query starting point |
| `limit` | int | No | `100` | - | Query the number of tasks |
| `filters` | array | No | - | - | Query task filtering criteria, such as task status and function type |
| `filters[].key` | string | No | - | `status`, `product_type` | Filtering dimensions, currently supporting filtering based on task status and other conditions |
| `filters[].values` | array | No | - | - | Filter value |

#### Request Body Field Notes

- `start_time`: Unix timestamp, in milliseconds
- `start_time`: The default value is end_time - 30 days
- `start_time`: Start time must be earlier than end time
- `end_time`: The default value is current time
- `end_time`: Unix timestamp, in milliseconds
- `end_time`: End time must be later than start time
- `cursor`: Use the next_cursor returned by the previous query
- `cursor`: When cursor is not empty, start_time and end_time are ignored
- `limit`: Maximum value: 500
- `filters`: Load with key/value format:
  ```json
  "filters": [
    {
      "key": "status", // Filter dimension by task status, fixed value: status
      "values": ["succeeded"]
    },
    {
      "key": "product_type", // Filter dimension by function type, fixed value: product_type
      "values": ["video"]
    }
  ]
  ```
- `filters[].key`: status: filter by task status
  - product_type: filter by function type
- `filters[].values`: status: submitted, processing, succeeded, failed
- `filters[].values`: product_type: video, image, try_on

### Request Example

```bash
curl --location 'https://api-singapore.klingai.com/tasks' \
  --header 'Content-Type: application/json' \
  --header "Authorization: Bearer ${KLING_API_KEY}" \
  --data '{
    "start_time": "1781193600000",
    "end_time": "1781516352968",
    "cursor": "",
    "limit": 500,
    "filters": [
      {
        "key": "status",
        "values": ["succeeded"]
      },
      {
        "key": "product_type",
        "values": ["video"]
      }
    ]
  }'
```

### Response Example

```json
{
  "code": 0, // Error code. See Error Codes for details
  "message": "string", // Error information
  "request_id": "string", // Request ID, generated by the system
  "data": {
    "result": [
      {
        "id": "string", // The task ID being queried
        "status": "string", // Task status, Enum values: submitted, processing, succeeded, failed
        "message": "string", // Task status information, displaying the failure reason when the task fails
        "create_time": 1781080778802, // Task creation time, Unix timestamp, unit ms
        "update_time": 1781080794151, // Task update time, Unix timestamp, unit ms
        "external_id": "string", // The custom task ID for this task (if any)
        "outputs": [
        {
          "type": "video", // When the generated result is "video", the return value and related fields vary by content type. Enum values: image, video, audio, element, voice
          "id": "string", // Video ID, generated by the system
          "url": "string", // Generated result URL with hotlink protection. (Generated results are retained for 30 days; save them promptly.)
          "watermark_url": "string", // URL for generating result with watermark, hotlink protection format
          "duration": "string" // The actual duration of the generated video file, in seconds. For the output video duration used for billing, see usage.output_duration.
        },
        {
          "type": "image", // When the generated result is "image", the return value and related fields vary by content type. Enum values: image, video, audio, element, voice
          "url": "string", // Generated result URL with hotlink protection. (Generated results are retained for 30 days; save them promptly.)
          "watermark_url": "string", // Image download URL with watermark, protected URL
          "group_id": "string" // Only appears when generating grouped images, used to mark grouping relationships
        },
        {
          "type": "audio", // When the generated result is "audio", the return value and related fields vary by content type. Enum values: image, video, audio, element, voice
          "id": "string", // Audio ID, generated by the system
          "mp3_url": "string", // Generated MP3 URL with hotlink protection. (Generated results are retained for 30 days; save them promptly.)
          "wav_url": "string", // Generated WAV URL with hotlink protection. (Generated results are retained for 30 days; save them promptly.)
          "mp3_duration": "string", // The duration of the generated MP3 format audio, in seconds
          "wav_duration": "string" // The duration of the generated WAV format audio, in seconds
        },
        {
          "type": "voice", // When the generated result is "voice", the return value and related fields vary by content type. Enum values: image, video, audio, element, voice
          "id": "string", // Voice ID, generated by the system
          "name": "string", // Voice name
          "url": "string", // Material download link
          "owned_by": "string", // Voice source, kling is the official voice library, and the number is the creator ID
          "status": "succeeded" // Voice status. Enum values: succeeded, deleted
        },
        {
          "type": "element", // When the generated result is "element", the return value and related fields vary by content type. Enum values: image, video, audio, element, voice
          "id": "string", // Element ID, generated by the system
          "name": "string", // Element name
          "description": "string", // Element description
          "element_type": "string", // Element type, divided into video character element and multi-image element, enumeration values are: video_character_elements and multi_image_elements
          "references": [ // Related materials of element
            {
              "type": "image", // When returning 'image' materials, the enumeration values for each content type are: image, video, voice
              "role": "string", // Image reference material attributes are divided into frontal reference images and other reference images, with enumeration values of frontal and reference, respectively
              "url": "string" // Material download link
            },
            {
              "type": "video", // When returning "video" materials, the enumeration values for each content type are: image, video, voice
              "role": "refer", // Video reference material attribute, fixed value: refer
              "url": "string" // Material download link
            },
            {
              "type": "voice", // When "voice" material is returned, enumeration values of each content type: image, video, voice
              "role": "refer", // Voice reference material attribute, fixed value: refer
              "url": "string", // Material download link
              "id": "string", // Voice ID
              "name": "string", // Voice name
              "owned_by": "string" // Voice source. kling means official voice library; numbers are creator IDs
            }
          ],
          "owned_by": "string", // Element source. kling means the official Element library; numbers are creator IDs
          "status": "string", // Element status. Enum values: succeeded, deleted
          "tags": [ // Element label related information
            {
              "id": 1, // Tag ID
              "name": "string", // Tag name
              "description": "string" // Tag description
            }
          ]
        }
      ],
        "usage": { // Usage: returned only after the task ends and usage is available; otherwise omitted. Available only for Kling 4.0 and Kling 4.0 Flash tasks.
          "input_duration": "8.03", // The total input video duration, including feature_video, base_video, and video character elements, returned as a string with two decimal places in seconds. Available only for Kling 4.0 and Kling 4.0 Flash tasks with video input. The duration is measured after system normalization, so it may differ slightly from the duration of the original video files.
          "output_duration": "5" // The output video duration used for billing, in seconds. Uses the duration specified in settings.duration when provided; otherwise, uses the generation duration specified in the prompt. If neither specifies a duration, the duration of base_video is rounded to the nearest whole second. If no base_video is provided, the default is 10 seconds.
        },
        "billing": [ // When task consumes balances from multiple cash types, the system will return multiple records.
          {
            "charge_type": "string", // Consumption account type: cash for balance, unit for resource package
            "cash_type": "string", // Balance type. Only applicable when charge_type=cash. If the consumption is the official quota, the parameter value is balance. If the consumption is the test quota, the parameter value is test_balance. If the consumption is the reward quota, the parameter value is reward_balance.
            "amount": "string", // Deduction amount; In the balance deduction situation (charge_type=cash), it represents the discount price deducted from the balance, and in the resource package deduction situation (charge_type=unit), it represents the deduction amount of units; decimal system
            "currency": "string", // Consumption unit, which only exists in the consumption balance scenario (charge_type=cash), with a fixed parameter value of CNY/USD
            "package_type": "string", // Consumable resource bundle type, which only exists in the consumable resource bundle scenario (charge_type=unit), with fixed enumeration values: video, image, audio
            "list_price": "string" // Balance deduction list price only exists in the consumption limit scenario (charge_type=cash)
          }
        ]
      }
    ],
    "count": 1, // Number of query results
    "next_cursor": "string", // Cursor for querying subsequent results
    "has_more": true // Whether there are more results based on cursor information
  }
}
```