> ## 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 4.0 Image to Video > The Kling 4.0 Image to Video API animates a start frame, optionally ending on a second image, into a 3–30 second 720p or 1080p video. > [!TIP] > > 1. After submission, a `task_id` will be returned. If you provided a `callback_url`, when the task status becomes `finished` or `failed`, a POST request will be sent to the `callback_url`. > 2. Regardless of whether `callback_url` is provided, you can retrieve the result through the unified [Query Task Status](https://docs.vidgo.ai/api-manual/task-management/status.md) endpoint. Kling 4.0 Image to Video animates a start frame into a 3–30 second video at 720p or 1080p. Add a second image and Kling 4.0 uses it as the end frame, generating the motion between the two. It suits product shots, character animation and before/after transitions. Kling 4.0 is Kuaishou's Kling AI video model. Vidgo exposes it as four model IDs: [Text to Video](https://docs.vidgo.ai/api-manual/video-series/kwaivgi-kling-v4-0-text-to-video.md), [Image to Video](https://docs.vidgo.ai/api-manual/video-series/kwaivgi-kling-v4-0-image-to-video.md), [Reference to Video](https://docs.vidgo.ai/api-manual/video-series/kwaivgi-kling-v4-0-reference-to-video.md) and [Video Edit](https://docs.vidgo.ai/api-manual/video-series/kwaivgi-kling-v4-0-video-edit.md). ## Models * **kwaivgi/kling-v4.0/image-to-video** — Image-to-video with Kling 4.0 from a start frame and an optional end frame. ## Features * Image-to-video up to 30 seconds from one start frame. * First and last frame control with a second image. * Single or multi-shot prompts. * 720p or 1080p output; the frame shape follows the input image. * Output includes an audio track. ## Input modes * **Start frame**: `image_urls` with one image. * **Start and end frame**: `image_urls` with two images, start frame first. Either mode takes a single `prompt` or a `multi_prompt` shot list: * **Single prompt**: send `prompt` and, optionally, `duration`. * **Multi-shot**: send `multi_prompt` with one entry per shot. The clip length is the sum of the shot durations; leave `duration` out or set it to that sum. ## Required parameters * `image_urls` (string\[]): One or two public HTTP(S) image URLs. The first is the start frame; the optional second is the end frame. * `prompt` (string) **or** `multi_prompt` (object\[]): send exactly one. * `prompt`: 1–26,000 characters after trimming. * `multi_prompt`: a non-empty list of shots `{prompt, duration?}`. Each shot `prompt` is 1–512 characters; each shot `duration` is an integer `1`–`30` (default `5`). The shot durations must total 3–30 seconds. ## Optional parameters * `duration` (integer): Output length, `3`–`30` seconds. Default `5`; with `multi_prompt` the default is the shot total, and an explicit value must equal it. * `resolution` (string): `720p` or `1080p`. Default `720p`. ## Output The finished task returns one MP4 video, with an audio track, in the `files` array of [Query Task Status](https://docs.vidgo.ai/api-manual/task-management/status.md) and the callback payload. ## Examples * **Start frame only**: one image of a dancer with a motion and music prompt, 5 seconds at 720p. * **Start and end frame, 1080p, with callback**: a bud and an open flower as start and end frames, an 8-second time-lapse and a `callback_url`. ## Notes * `aspect_ratio` is not supported on this ID because the input image sets the frame; sending it returns 400. * To guide the video with extra reference images, reference videos or subjects, use [Kling 4.0 Reference to Video](https://docs.vidgo.ai/api-manual/video-series/kwaivgi-kling-v4-0-reference-to-video.md). * Fields not listed above return 400. `model` and `callback_url` belong at the request root, not inside `input`. * Credits are reserved at submission and depend on `resolution` and the output `duration`. A failed task is refunded in full. See the [pricing page](https://vidgo.ai/apis/api-pricing) for current rates. * Output is 720p or 1080p only; there is no 4K or HDR tier, no audio on/off switch and no `seed` on this model. ## OpenAPI ````yaml api-manual/video-series/kwaivgi-kling-v4-0-image-to-video.json POST /api/generate/submit openapi: 3.0.0 info: title: Vidgo API - Kling 4.0 Image to Video description: >- The Kling 4.0 Image to Video API animates a start frame, optionally ending on a second image, into a 3–30 second 720p or 1080p video. version: 1.0.0 servers: - url: https://api.vidgo.ai description: Production server security: - BearerAuth: [] paths: /api/generate/submit: post: tags: - Video Series summary: Kling 4.0 Image to Video description: >- Send `image_urls` and exactly one of `prompt` or `multi_prompt`. `aspect_ratio` and reference fields are not supported and return 400. Image URLs must be public HTTP(S) URLs without embedded credentials. operationId: submit_kwaivgi_kling_v4_0_image_to_video requestBody: required: true content: application/json: schema: type: object required: - model - input properties: model: type: string description: Model ID. Use `kwaivgi/kling-v4.0/image-to-video`. example: kwaivgi/kling-v4.0/image-to-video callback_url: type: string format: uri nullable: true description: >- Optional public HTTP(S) endpoint that receives a POST when the task becomes `finished` or `failed`. HTTPS is recommended. Omit it, or send `null` or an empty string, to disable callbacks. example: https://your-domain.com/callback input: type: object required: - image_urls properties: image_urls: type: array items: type: string format: uri minItems: 1 maxItems: 2 example: - https://example.com/start.png description: >- One or two public HTTP(S) image URLs. The first image is the start frame; an optional second image is the end frame. prompt: type: string minLength: 1 maxLength: 26000 description: >- Text prompt, 1–26,000 characters after trimming. Send exactly one of `prompt` or `multi_prompt`. multi_prompt: type: array items: type: object required: - prompt properties: prompt: type: string minLength: 1 maxLength: 512 description: Shot prompt, 1–512 characters. duration: type: integer minimum: 1 maximum: 30 default: 5 description: Shot length in seconds (integer). additionalProperties: false description: One shot. minItems: 1 description: >- Multi-shot prompt: a non-empty list of shots, each with its own `prompt` and optional `duration`. Shot durations must total 3–30 seconds. Send exactly one of `prompt` or `multi_prompt`. duration: type: integer minimum: 3 maximum: 30 default: 5 description: >- Output length in seconds (integer). With `multi_prompt` it defaults to the shot total and, if sent, must equal it. resolution: type: string enum: - 720p - 1080p default: 720p description: Output resolution. It sets the billing rate. additionalProperties: false description: Generation parameters. examples: start_frame: summary: Start frame only value: model: kwaivgi/kling-v4.0/image-to-video input: image_urls: - https://example.com/dancer.png prompt: >- The dancer spins and her red dress flares out, the camera slowly circles her, soft piano music duration: 5 resolution: 720p start_end_frame: summary: Start and end frame, 1080p, with callback value: model: kwaivgi/kling-v4.0/image-to-video callback_url: https://your-domain.com/callback input: image_urls: - https://example.com/bud.png - https://example.com/flower.png prompt: >- Time-lapse: the bud slowly opens into a full flower as morning light moves across the petals duration: 8 resolution: 1080p responses: '200': description: Task submitted content: application/json: schema: type: object required: - code - data properties: code: type: integer enum: - 200 description: HTTP status code. data: type: object required: - task_id - status - created_time properties: task_id: type: string description: >- Task ID. Use it with [Query Task Status](/api-manual/task-management/status). status: type: string enum: - not_started description: Initial task status. created_time: type: string format: date-time description: Time the task was created (ISO 8601). example: code: 200 data: task_id: task-unified-1762160000-abc123 status: not_started created_time: '2026-11-03T10:30:00' '400': description: >- Invalid input, unsupported field, 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: {} description: Error message. '401': description: Invalid credentials content: application/json: schema: type: object required: - detail properties: detail: oneOf: - type: string - type: object additionalProperties: true - type: array items: {} description: Error message. '403': description: Access denied content: application/json: schema: type: object required: - detail properties: detail: oneOf: - type: string - type: object additionalProperties: true - type: array items: {} description: Error message. '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: {} description: Error message. '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: {} description: Error message. '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: {} description: Error message. '500': description: Internal error content: application/json: schema: type: object required: - detail properties: detail: oneOf: - type: string - type: object additionalProperties: true - type: array items: {} description: Error message. '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: {} description: Error message. '503': description: The requested model is temporarily unavailable content: application/json: schema: type: object required: - detail properties: detail: oneOf: - type: string - type: object additionalProperties: true - type: array items: {} description: Error message. components: securitySchemes: BearerAuth: type: http scheme: bearer bearerFormat: API Key description: >- All API endpoints require Bearer Token authentication Get your API Key: Go to **Dashboard → API Key** ([API Key Management Page](https://vidgo.ai/apis/dashboard/api-key)) to get your API Key Add it to the request header: ``` Authorization: Bearer VIDGO_API_KEY ``` ```` This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.