Inference Logoinference shell

Kling Video V4

Kling V4.0 video generation. Text-to-video and image-to-video with start and end frames, 3-30s billed per second, 720p or 1080p, native audio and automatic shot-splitting.

text to videoimage to videonative audio
run in browser →run via APIrun with your agent
maker
klingai
category
video
input → output
text → video, image → video
runs via
api, javascript and python sdk, belt cli, mcp
updated
2026-11-11
price
$0.157/s at 720p, $0.235/s at 1080p

api reference

about

kling v4.0 video generation. text-to-video and image-to-video with start and end frames, 3-30s billed per second, 720p or 1080p, native audio and automatic shot-splitting.

get an api key

create one in settings → api keys. the examples read it from INFERENCE_API_KEY.

bash
1export INFERENCE_API_KEY="inf_your_key"

1. calling the api

install the client

nothing to install. any http client works; the examples use curl, and jq to read responses. every response wraps its result in a data field.

run and get result

send "wait": true to hold the connection until the task finishes. without it the call returns right away with the task still running.

bash
12# "wait": true holds the connection until the task finishes.3# the response is {"data": {"id", "status", "status_text", "output", ...}}4curl -X POST https://api.inference.sh/apps/run \5  -H "Authorization: Bearer $INFERENCE_API_KEY" \6  -H "Content-Type: application/json" \7  -d '{8    "app": "klingai/video-v4",9    "input": {10      "prompt": "A cinematic drone shot sweeping over a coastal city at golden hour, waves crashing against the harbor"11    },12    "wait": true13  }'

stream live updates

get real-time progress updates as the task runs. ideal for showing progress bars, partial results, or long-running tasks. send "stream": true and the response is a server-sent event stream that ends when the task does.

bash
12# "stream": true answers with server-sent events until the task finishes3curl -N -X POST https://api.inference.sh/apps/run \4  -H "Authorization: Bearer $INFERENCE_API_KEY" \5  -H "Content-Type: application/json" \6  -d '{7    "app": "klingai/video-v4",8    "input": {9      "prompt": "A cinematic drone shot sweeping over a coastal city at golden hour, waves crashing against the harbor"10    },11    "stream": true12  }'

run in the background

start the task and get its id back right away, then check on it later. for long tasks, or when you'd rather be called back, see webhooks.

bash
1# without "wait" the call returns the task right away (status 1, "received")2TASK_ID=$(curl -s -X POST https://api.inference.sh/apps/run \3  -H "Authorization: Bearer $INFERENCE_API_KEY" \4  -H "Content-Type: application/json" \5  -d '{6    "app": "klingai/video-v4",7    "input": {8      "prompt": "A cinematic drone shot sweeping over a coastal city at golden hour, waves crashing against the harbor"9    }10  }' | jq -r '.data.id')1112# later: read its state. done when status is 10 (completed), 11 (failed) or 12 (cancelled)13curl -s https://api.inference.sh/tasks/$TASK_ID \14  -H "Authorization: Bearer $INFERENCE_API_KEY" | jq '.data | {status, status_text, output}'

2. authentication

the api uses api keys for authentication. see the authentication docs for detailed setup instructions.

3. files

file inputs are automatically handled by the sdk. you can pass local paths, urls, or base64 data.

automatic upload

pass urls directly or use data uris for inline content.

bash
1# pass URLs or data URIs as input values2curl -X POST https://api.inference.sh/apps/run \3  -H "Authorization: Bearer $INFERENCE_API_KEY" \4  -H "Content-Type: application/json" \5  -d '{6    "app": "klingai/video-v4",7    "input": {8      "image": "https://example.com/image.png",9      "audio": "data:audio/mp3;base64,..."10    },11    "wait": true12  }'

manual upload

you can also upload files manually and use the returned url.

bash
1# 1. create the file: the response has an upload_url and the file's uri2FILE=$(curl -s -X POST https://api.inference.sh/files \3  -H "Authorization: Bearer $INFERENCE_API_KEY" \4  -H "Content-Type: application/json" \5  -d '{"files": [{"filename": "image.png", "content_type": "image/png"}]}')67# 2. PUT the bytes to upload_url8curl -X PUT "$(echo "$FILE" | jq -r '.data[0].upload_url')" \9  -H "Content-Type: image/png" \10  --data-binary @image.png1112# 3. pass the uri as an input value13echo "$FILE" | jq -r '.data[0].uri'

4. webhooks

get notified when a task completes by providing a webhook url. when the task reaches a terminal state (completed, failed, or cancelled), a POST request is sent to your url with the task result.

bash
1curl -X POST https://api.inference.sh/apps/run \2  -H "Authorization: Bearer $INFERENCE_API_KEY" \3  -H "Content-Type: application/json" \4  -d '{5    "app": "klingai/video-v4",6    "input": {7        "prompt": "A cinematic drone shot sweeping over a coastal city at golden hour, waves crashing against the harbor"8    },9    "webhook": "https://your-server.com/webhook"10  }'

webhook payload

your endpoint receives a JSON POST with the task result:

json
1{2  "event": "task.completed",3  "timestamp": "2024-01-15T10:30:05Z",4  "data": {5    "id": "task_abc123",6    "short_id": "abc123",7    "status": 10,8    "status_text": "completed",9    "output": { ... },10    "created_at": "2024-01-15T10:30:00Z",11    "updated_at": "2024-01-15T10:30:05Z"12  }13}
eventstringtask.completed, task.failed or task.cancelled
timestampstringiso timestamp of the delivery
data.idstringtask id
data.short_idstringshort task id
data.statusnumberterminal status (10=completed, 11=failed, 12=cancelled, 13=rejected)
data.status_textstringthe status as a word: completed, failed or cancelled
data.outputobjecttask output (when completed)
data.errorstringerror message (when failed, omitted otherwise)
data.session_idstringsession id (when the task ran in a session, omitted otherwise)
data.created_atstringiso timestamp
data.updated_atstringiso timestamp

5. schema

input

promptstring*

text prompt describing the video content. a duration set here takes precedence over one named in the prompt.

example: "A cinematic drone shot sweeping over a coastal city at golden hour, waves crashing against the harbor"
imagestring(file)

start frame image for image-to-video. formats: jpg, jpeg, png. max 30mb, min 300px per side, aspect ratio between 2:5 and 5:2.

end_imagestring(file)

end frame image. requires image to be set as start frame.

resolutionstring

video resolution.

default: "1080p"
options:"720p""1080p"
aspect_ratiostring

video aspect ratio. text-to-video only; with an image the video follows the image.

default: "16:9"
options:"21:9""16:9""9:16""1:1"
durationinteger

video duration in seconds (3-30). billed per second.

default: 5min:3max:30

output

videostring(file)*

the generated video file.

other video apps

Pika H3 Flex (self-hosted)

pika/pika-h3-flex-oss

GPU time, billed per millisecond

Pika H3 Flex Upscale

pika/pika-h3-flex-upscale

$0.05-$0.14/sec (480p src), $0.03-$0.12/sec (768p src); 1080p/2K/4K targets

Pika H3 Flex Reference to Video

pika/pika-h3-flex-reference

$0.06/sec 480p, $0.12/sec 768p, $0.15/sec 1080p, $0.16/sec 2k, $0.20/sec 4k (output+input video sec). Stems: $0.001/sec

Pika H3 Flex

pika/pika-h3-flex

$0.02/sec 480p, $0.04/sec 768p, $0.07/sec 1080p, $0.08/sec 2K, $0.16/sec 4K; stems +$0.001/stem-sec

Gemini Omni 1.2 Flash

google/gemini-omni-1-2-flash

$0.0232/sec 360p, $0.0695/sec 720p, $0.1043/sec 1080p, $0.2085/sec 4K, plus $1.50/M input and $9.00/M thinking tokens

more from klingai

Kling Image V2

klingai/image-v2

$0.014-$0.056/image, t2i: $0.014/image, i2i: $0.028/image, multi-image: $0.056/image

Kling Image O1

klingai/image-o1

$0.028/run

Kling Image 3O

klingai/image-3o

$0.028/image (1K/2K), $0.056/image (4K)

Kling Image V1

klingai/image-v1

$0.0035/image

new models

  1. MiniMax H3 Image

    minimax/h3-image

    image$2.30/M text in, $1.50/M image in, $3.80/M image out (token-based)

  2. Pika H3 Flex (self-hosted)

    pika/pika-h3-flex-oss

    videoGPU time, billed per millisecond

  3. Pika H3 Flex Audio Stems

    pika/pika-h3-flex-audio-stems

    audio$0.001/stem-sec (3 stems: dialogue, music, effect)

  4. Pika H3 Flex Upscale

    pika/pika-h3-flex-upscale

    video$0.05-$0.14/sec (480p src), $0.03-$0.12/sec (768p src); 1080p/2K/4K targets

  5. Pika H3 Flex Reference to Video

    pika/pika-h3-flex-reference

    video$0.06/sec 480p, $0.12/sec 768p, $0.15/sec 1080p, $0.16/sec 2k, $0.20/sec 4k (output+input video sec). Stems: $0.001/sec

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