Kling Image API

Quick Start

Authentication

Add Authorization header with Bearer token to all requests:

Authorization: Bearer YOUR_API_KEY

Available Models

Pricing (up to 60% off)

Endpoints

Request Parameters

Text-to-Image / Image-to-Image

Multi-Image Reference (kling-multi-image)

Code Examples

curl -X POST https://api.apimodels.app/v1/images/generations \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "kling-v3-image",
    "prompt": "A majestic snow-capped mountain at sunrise with golden light",
    "aspect_ratio": "16:9",
    "resolution": "2k",
    "n": 1
  }'

Response Format

Create Task Response

{
  "code": 200,
  "msg": "success",
  "data": {
    "taskId": "clxxx...",
    "state": "pending",
    "model": "kling-image-gen/kling-v3"
  }
}

Success Response

{
  "code": 200,
  "msg": "success",
  "data": {
    "taskId": "clxxx...",
    "state": "completed",
    "model": "kling-image-gen/kling-v3",
    "resultUrls": ["https://...image.png"],
    "createTime": 1705123450000,
    "completeTime": 1705123500000
  }
}

Failed Response

{
  "code": 200,
  "msg": "success",
  "data": {
    "taskId": "clxxx...",
    "state": "failed",
    "model": "kling-image-gen/kling-v3",
    "failMsg": "Content policy violation"
  }
}

Webhook Callback (callback_url)

Pass callback_url in the create request. When the task reaches the completed or failed terminal state, our server sends a single HTTP POST to that URL with Content-Type: application/json (no signing header). Delivery is retried up to 3 times (exponential backoff 1s/2s/4s, 10s per attempt); if still unsuccessful, a background job keeps retrying for up to 30 minutes until your endpoint returns 2xx.

Payload Structure

POST {your callback_url}
Content-Type: application/json

{
  "code": 200,
  "msg": "success",
  "data": {
    "taskId": "clxxx...",
    "model": "kling-image-gen/kling-v3",
    "state": "completed" | "failed",
    "param": "<JSON string>",            // request params, JSON.parse once
    "resultJson": "<JSON string> | null", // result object, JSON.parse once
    "failCode": null | "CONTENT_MODERATION | INVALID_INPUT | INSUFFICIENT_BALANCE | UPSTREAM_BUSY | UPSTREAM_FAILED | TIMEOUT | INTERNAL_ERROR | OTHER",
    "failMsg": null | "string",
    "retryable": true | false,           // present when state=failed: safe to retry/fallback
    "costTime": 12345,                    // duration in ms
    "completeTime": 1705123500000,        // ms epoch
    "createTime": 1705123450000           // ms epoch
  }
}

Note: data.param and data.resultJson are both JSON strings — call JSON.parse once on each.

Image task: shape after JSON.parse(data.resultJson)

{
  "resultUrls": [
    "https://r2.apimodels.app/images/xxx.png"
  ]
}

resultUrls is an array of Cloudflare R2-hosted image URLs. Multi-image runs return more than one. When state=failed, resultJson is typically null or {"resultUrls":[]} — do not assume a link is present.

Node.js receiver example

app.post('/webhook/kling-image', express.json(), (req, res) => {
  const { taskId, state, resultJson, failMsg } = req.body.data
  if (state === 'completed') {
    const { resultUrls } = JSON.parse(resultJson)
    console.log('image ready', taskId, resultUrls[0])
  } else {
    console.warn('image failed', taskId, failMsg)
  }
  res.status(200).end()                 // must be 2xx, otherwise we retry
})

Notes

• -A task stops retrying only after a 2xx response — once delivered it is never pushed again.
• -Callbacks are not signed today. Embed a random token in your callback_url path and verify it on receipt.
• -Use a public HTTPS endpoint that responds within 10 seconds (per-attempt timeout).

Task States

Error Codes

Important Notes

• *Image files are stored for 30 days, download promptly
• *All prices are per image; multiply by n for total cost
• *Prompt supports max 2500 characters
• *Multi-image reference supports up to 4 subject images
• *Poll every 5-10 seconds to check status
• *kling-v2-new style transfer resolution matches input image