Kling Video V2.1 Pro

POST/v1/run

Kling Video V2.1 Pro is KwaiVGI's image-to-video AI model. Bring static images to life with fluid animation, consistent character motion, and professional-grade video output.

Request body

Submit an async generation request. The model field selects the model; other fields are model-specific input parameters.

stringmodelrequired

Model identifier. Set to kwaivgi/kling-video/v2.1/pro/image-to-video.

Default: kwaivgi/kling-video/v2.1/pro/image-to-video

stringpromptrequired

Text prompt that describes the image or asset to generate.

stringimagerequired

URL of the image to be used for the video

Optional<string>end_image

URL of the image to be used for the end of the video

Optional<integer>duration

The duration of the generated video in seconds

Allowed values: 5, 10

Default: 5

Response Schema

The submit endpoint returns a run response. If its status is pending or running, poll GET /v1/run/{id} with the returned opaque ID until it reaches a terminal state.

stringidrequired

Opaque SandBase run identifier. Use it exactly as returned; no prefix is guaranteed.

stringstatusrequired

Current public run status.

Allowed values: pending, running, completed, failed, timeout

Optional<string>model

Public SandBase model name used for this run.

Optional<array<object>>outputs

Present only for completed runs. Each object is capability-specific; inspect the selected model schema for its fields.

Optional<object>error

Present only for failed or timeout runs. Contains a public error type and sanitized message.

Optional<string>error.type

Stable public error category.

Optional<string>error.message

Sanitized error message safe to show to clients.

Optional<object>usage

Usage details when available.

Model capabilities

array<string>capability_tagsrequired

Capabilities declared by the model registry.

Default: image-to-video

stringexecution_moderequired

Execution mode declared by the model registry.

Default: async

# 1. Submit a generation request
curl -X POST https://api.sandbase.ai/v1/run \
  -H "Authorization: Bearer $SANDBASE_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
  "model": "kwaivgi/kling-video/v2.1/pro/image-to-video",
  "prompt": "Warm, incandescent streetlights paint the rain-slicked cobblestones in pools of amber light as a couple walks hand-in-hand, their silhouettes stark against the blurry backdrop of a city shrouded in a gentle downpour; the camera lingers on the subtle textures of their rain-soaked coats and the glistening reflections dancing on the wet pavement, creating a sense of intimate vulnerability and shared quietude.",
  "image": "https://v3.fal.media/files/lion/_I_io6Gtk83c72d-afXf8_image.webp",
  "duration": 5
}'

# 2. If the response is still running, poll the returned id
curl https://api.sandbase.ai/v1/run/f3d2e8a1-7c4b-4a12-9d2e-123456789abc \
  -H "Authorization: Bearer $SANDBASE_API_KEY"

Response202 Accepted

{
  "id": "f3d2e8a1-7c4b-4a12-9d2e-123456789abc",
  "model": "kwaivgi/kling-video/v2.1/pro/image-to-video",
  "status": "running"
}