> ## Documentation Index > Fetch the complete documentation index at: https://docs.vidgo.ai/llms.txt > Use this file to discover all available pages before exploring further. # Kling 2.1 Image to Video > Kling 2.1 Standard image-to-video with a required start frame. 1. Submit the request with `VIDGO_API_KEY`. A `task_id` is returned immediately. Keep it until the task reaches `finished` or `failed`. 2. Use [Query Task Status](/api-manual/task-management/status) to retrieve the result. If you provide a `callback_url`, Vidgo sends the result to your [webhook](/api-manual/task-management/webhooks) when the task finishes or fails. # Kling 2.1 Image to Video Kling 2.1 Standard image-to-video with a required start frame. ## Available Models * **kwaivgi/kling-video/v2.1/standard/image-to-video** - Generate video from image input. ## Duration Options * **5, 10 seconds** - Set `duration` as an integer. Optional. Default: **5 seconds** when omitted. Strings, booleans, null and fractional values are rejected. ## Key Features * Generate video from image input. * Use `start_image_url` to supply the starting frame. * For an optional ending frame, use the [Pro endpoint](/api-manual/video-series/kwaivgi-kling-video-v2-1-pro-image-to-video). ## Advanced Parameters Set `model` and optional `callback_url` at the request root. Place all workflow parameters, including output options, inside `input`. Send only the input fields supported by this workflow. Unsupported `input` fields are rejected before credits are deducted. Input URLs must use HTTP(S), include a hostname, and contain no embedded credentials. ### Prompt * `prompt`: Required. Describe the scene and desired motion. Length: **1-5,000 characters**. * The value must be a string and must not be blank after trimming. Non-string values are rejected. ### Start Image URL * `start_image_url`: Required. Provide the starting frame URL. Use a publicly accessible HTTP(S) URL without credentials or whitespace. Empty URLs and null are rejected. ### Negative Prompt * `negative_prompt`: Optional. Describe content to avoid. ## Billing Factors Billed per video according to the selected model tier (Standard or Pro) and video duration (`duration`). Credits are deducted on submission and refunded if the task fails. ## OpenAPI ````yaml api-manual/video-series/kwaivgi-kling-video-v2-1-standard-image-to-video.json POST /api/generate/submit openapi: 3.0.0 info: title: Vidgo API - Kling 2.1 Image to Video description: Kling 2.1 Standard image-to-video with a required start frame. version: 1.0.0 servers: - url: https://api.vidgo.ai security: - BearerAuth: [] paths: /api/generate/submit: post: tags: - Video Series summary: Kling 2.1 Image to Video description: >- Kling 2.1 Standard image-to-video with a required start frame. Unsupported input fields are rejected before credits are deducted. Billed per video according to the selected model tier (Standard or Pro) and video duration (`duration`). operationId: submit_kwaivgi_kling_video_v2_1_standard_image_to_video requestBody: required: true content: application/json: schema: type: object required: - model - input additionalProperties: true properties: model: type: string example: kwaivgi/kling-video/v2.1/standard/image-to-video input: type: object required: - prompt - start_image_url properties: prompt: type: string maxLength: 5000 minLength: 1 description: >- Required nonblank string, maximum 5,000 Unicode characters after trimming. duration: type: integer enum: - 5 - 10 default: 5 description: >- Optional integer: 5 or 10 seconds. Defaults to 5 when omitted. Strings, booleans, null and fractional durations are rejected. start_image_url: type: string format: uri description: >- Required first-frame public HTTP(S) URL, with a hostname and no credentials or whitespace. Empty URLs and null are rejected. negative_prompt: type: string description: Negative prompt. additionalProperties: false callback_url: type: string nullable: true description: >- Optional public HTTP(S) endpoint for task completion notifications. HTTPS is recommended. Omit, use null, or use an empty string to disable callbacks. description: >- Keep model and callback_url at the root. Unknown root fields are ignored; unsupported input fields are rejected. examples: basic: summary: Basic workflow value: model: kwaivgi/kling-video/v2.1/standard/image-to-video input: prompt: >- A quiet forest under soft morning light, with natural detail. start_image_url: https://example.com/image.png duration: 5 callback: summary: Receive a completion callback value: model: kwaivgi/kling-video/v2.1/standard/image-to-video input: prompt: >- A quiet forest under soft morning light, with natural detail. start_image_url: https://example.com/image.png duration: 5 callback_url: https://your-domain.com/callback responses: '200': description: Task submitted content: application/json: schema: type: object required: - code - data properties: code: type: integer enum: - 200 data: type: object required: - task_id - status - created_time properties: task_id: type: string status: type: string enum: - not_started - running - finished - failed created_time: type: string format: date-time example: code: 200 data: task_id: task-unified-example status: running created_time: '2026-09-10T08:00:00' '400': description: >- Invalid input, unsupported tier, inaccessible media, or insufficient credits content: application/json: schema: type: object required: - detail properties: detail: oneOf: - type: string - type: object additionalProperties: true - type: array items: {} '401': description: Invalid credentials content: application/json: schema: type: object required: - detail properties: detail: oneOf: - type: string - type: object additionalProperties: true - type: array items: {} '403': description: Access denied content: application/json: schema: type: object required: - detail properties: detail: oneOf: - type: string - type: object additionalProperties: true - type: array items: {} '404': description: Unknown or disabled model content: application/json: schema: type: object required: - detail properties: detail: oneOf: - type: string - type: object additionalProperties: true - type: array items: {} '408': description: Request timed out content: text/plain: schema: type: string example: Request timeout '422': description: Invalid JSON or non-object request body content: application/json: schema: type: object required: - detail properties: detail: oneOf: - type: string - type: object additionalProperties: true - type: array items: {} '429': description: Rate or API key credit limit exceeded content: application/json: schema: type: object required: - detail properties: detail: oneOf: - type: string - type: object additionalProperties: true - type: array items: {} '500': description: Internal error content: application/json: schema: type: object required: - detail properties: detail: oneOf: - type: string - type: object additionalProperties: true - type: array items: {} '502': description: Unable to create the upstream generation task content: application/json: schema: type: object required: - detail properties: detail: oneOf: - type: string - type: object additionalProperties: true - type: array items: {} '503': description: Model configuration or capability is not approved content: application/json: schema: type: object required: - detail properties: detail: oneOf: - type: string - type: object additionalProperties: true - type: array items: {} components: securitySchemes: BearerAuth: type: http scheme: bearer description: Use VIDGO_API_KEY. ````