Kling 2.1

Overview

Kling 2.1 is a tiered Kuaishou video model for image-to-video generation and master-quality text-to-video generation. Use this page when you are ready to call the API after trying the model in the APIXO playground.

Capability	Value
Model ID	`kling-2-1`
Modes	`standard-image-to-video`, `pro-image-to-video`, `master-text-to-video`, `master-image-to-video`
Prompt length	1-5000 characters
Duration	`5` or `10` seconds
Reference images	None for `master-text-to-video`; exactly 1 for `standard-image-to-video` and `master-image-to-video`; 1-2 for `pro-image-to-video`
Aspect ratios	`16:9`, `9:16`, `1:1` for `master-text-to-video` only
Output format	MP4 URLs in `resultJson.resultUrls`

Endpoint and authentication

Base URL:

https://api.apixo.ai/api/v1

Method	Endpoint	Purpose
`POST`	`/generateTask/kling-2-1`	Submit a generation task
`GET`	`/statusTask/kling-2-1?taskId={taskId}`	Poll task status and retrieve results

All requests require your APIXO API key:

Authorization: Bearer YOUR_API_KEY

Submit requests also require:

Content-Type: application/json

Copy-paste async quickstart

This minimal request submits a standard image-to-video task and returns a taskId.

curl -X POST "https://api.apixo.ai/api/v1/generateTask/kling-2-1" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "request_type": "async",
    "input": {
      "mode": "standard-image-to-video",
      "prompt": "animate this still life scene with subtle camera movement",
      "duration": 5,
      "image_urls": [
        "https://example.com/source.jpg"
      ]
    }
  }'

Successful response:

{
  "code": 200,
  "message": "success",
  "data": {
    "taskId": "task_12345678"
  }
}

Save the taskId; you need it to poll for the final result.

Poll for result

curl -X GET "https://api.apixo.ai/api/v1/statusTask/kling-2-1?taskId=task_12345678" \
  -H "Authorization: Bearer YOUR_API_KEY"

Processing response:

{
  "code": 200,
  "message": "success",
  "data": {
    "taskId": "task_12345678",
    "state": "processing",
    "createTime": 1767965610929
  }
}

Success response:

{
  "code": 200,
  "message": "success",
  "data": {
    "taskId": "task_12345678",
    "state": "success",
    "resultJson": "{\"resultUrls\":[\"https://file.apixo.ai/xxx.mp4\"]}",
    "createTime": 1767965610929,
    "completeTime": 1767965710132,
    "costTime": 99203
  }
}

Failed response:

{
  "code": 200,
  "message": "success",
  "data": {
    "taskId": "task_12345678",
    "state": "failed",
    "failCode": "SensitiveContent",
    "failMsg": "Content violates upstream policy, please adjust the prompt",
    "createTime": 1767965610929,
    "completeTime": 1767965620132,
    "costTime": 9203
  }
}

Parse resultJson after state becomes success:

const payload = JSON.parse(data.resultJson);
const videoUrls = payload.resultUrls;

Request body

Standard image-to-video

{
  "request_type": "async",
  "input": {
    "mode": "standard-image-to-video",
    "prompt": "animate this still life scene with subtle camera movement",
    "duration": 5,
    "image_urls": [
      "https://example.com/source.jpg"
    ],
    "negative_prompt": "blur, low quality",
    "cfg_scale": 0.6
  }
}

Pro image-to-video

{
  "request_type": "async",
  "input": {
    "mode": "pro-image-to-video",
    "prompt": "city skyline timelapse from day to night",
    "duration": 10,
    "image_urls": [
      "https://example.com/start.jpg",
      "https://example.com/end.jpg"
    ],
    "cfg_scale": 0.4
  }
}

Master text-to-video

{
  "request_type": "async",
  "input": {
    "mode": "master-text-to-video",
    "prompt": "a futuristic drone flying through neon-lit streets at night",
    "duration": 5,
    "aspect_ratio": "9:16",
    "negative_prompt": "grainy, noisy, static",
    "cfg_scale": 0.3
  }
}

Master image-to-video

{
  "request_type": "async",
  "input": {
    "mode": "master-image-to-video",
    "prompt": "turn this product photo into a premium cinematic reveal",
    "duration": 5,
    "image_urls": [
      "https://example.com/product.jpg"
    ]
  }
}

Parameters

request_type

string

default:"async"

Result delivery mode. Use async for polling with statusTask, or callback for webhook delivery.

callback_url

string

Required when request_type is callback. Must be a public HTTPS URL that can receive the final task payload. See Webhooks.

input

object

required

Kling 2.1 input parameters.

Show properties

mode

string

required

Generation mode. Supported values: standard-image-to-video, pro-image-to-video, master-text-to-video, master-image-to-video.

prompt

string

required

Text prompt describing the video. Must be a non-empty string with 1-5000 characters.

duration

integer

required

Video duration in seconds. Supported values: 5 or 10.

image_urls

string[]

Reference image URLs. Do not send this field for master-text-to-video. Send exactly 1 URL for standard-image-to-video and master-image-to-video. Send 1-2 URLs for pro-image-to-video; the second URL is accepted as an end-frame reference on routes that support tail-frame continuity.

aspect_ratio

string

default:"16:9"

Output aspect ratio for master-text-to-video. Supported values: 16:9, 9:16, 1:1. If omitted in master-text-to-video, the backend sends 16:9. Image-to-video modes do not forward this field.

negative_prompt

string

Negative prompt for unwanted visual elements. Maximum length is 500 characters. Blank values are not forwarded.

cfg_scale

number

Prompt guidance scale. Supported range is 0 to 1 with step 0.1. Recommended range: 0.3-0.7.

Response format

Submit task response

POST /generateTask/kling-2-1 returns a task ID when the task is accepted:

code

integer

API status code. 200 means the task was accepted.

message

string

Human-readable status message.

data.taskId

string

Unique task identifier used with the status endpoint.

Status response fields

taskId

string

Unique task identifier.

state

string

Current task state: pending, processing, success, or failed.

resultJson

string

JSON string containing the generated video URLs. Present when state is success.

failCode

string

Machine-readable failure code. Present when state is failed.

failMsg

string

Human-readable failure message. Present when state is failed.

createTime

integer

Task creation timestamp in Unix milliseconds.

completeTime

integer

Task completion timestamp in Unix milliseconds. Present after completion.

costTime

integer

Processing duration in milliseconds. Present after successful completion and often present after failure.

Webhook callback mode

Use callback mode when your backend should receive the final result automatically instead of polling.

curl -X POST "https://api.apixo.ai/api/v1/generateTask/kling-2-1" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "request_type": "callback",
    "callback_url": "https://your-server.com/webhooks/apixo",
    "input": {
      "mode": "master-text-to-video",
      "prompt": "a futuristic drone flying through neon-lit streets at night",
      "duration": 5,
      "aspect_ratio": "16:9"
    }
  }'

The callback payload uses the same unified response format as the status endpoint. See Webhooks for delivery requirements and retry behavior.

Billing

Kling 2.1 is billed per generated video. The selected mode determines the tier, and duration determines the unit price.

Mode	Tier	5 seconds	10 seconds
`standard-image-to-video`	Standard	`$0.20 / video`	`$0.40 / video`
`pro-image-to-video`	Pro	`$0.35 / video`	`$0.70 / video`
`master-text-to-video`	Master	`$1.00 / video`	`$2.00 / video`
`master-image-to-video`	Master	`$1.00 / video`	`$2.00 / video`

For current route and market comparison pricing, see Pricing.

Latency and polling

Actual latency may vary by prompt complexity, selected tier, input image size, route, and current queue load.

Duration	Typical generation time	Recommended first poll	Poll interval
`5` seconds	60s-90s	60s after task creation	5s-10s
`10` seconds	90s-120s	60s after task creation	5s-10s

For production video workloads, use callback mode to avoid frequent polling. Result URLs are stored through APIXO and are generally available for 15 days, so download important outputs promptly.

Rate limits and concurrency can vary by account, API key, and route. If you receive 429, slow down requests and retry with backoff. For account-level details, see System APIs.

Errors and troubleshooting

HTTP errors

Code	Meaning	What to do
`400`	Invalid request body, missing required field, unsupported mode, or rejected input	Fix the request before retrying
`401`	Missing or invalid API key	Check the `Authorization` header
`402`	Insufficient balance or quota	Add balance or switch account/key
`403`	Key or route cannot access the model	Check permissions and routing settings
`429`	Rate limit or concurrency limit reached	Retry with exponential backoff
`500`	Server error	Retry with backoff
`502`	Upstream service error	Retry with backoff
`504`	Upstream timeout	Retry or use callback mode for long-running jobs

Task failure codes

Exact failCode values can vary because upstream errors are normalized before they are returned.

Fail code	Meaning	What to do
`Missing required parameter`	A required field such as `input`, `mode`, `prompt`, `duration`, `image_urls`, or `callback_url` is missing	Add the missing field
`Invalid parameter type`	A field has the wrong JSON type	Check `prompt`, `duration`, `image_urls`, `aspect_ratio`, `negative_prompt`, and `cfg_scale`
`Invalid parameter value`	A field has an unsupported value	Check `mode`, `duration`, `aspect_ratio`, and `cfg_scale`
`Param length exceeded`	Prompt, negative prompt, or image count exceeds the backend limit	Shorten text or reduce image count
`ImageNotAccess`	An input image URL could not be fetched	Use a public, direct HTTP(S) image URL
`SensitiveContent`, `PromptInvalid`, `ProhibitedContentDetected`, `NSFW`	Prompt, input image, or output failed safety checks	Change the prompt or image
`RateLimited`	Upstream rate limit was reached	Retry with backoff
`Timeout`	Upstream service timed out	Retry, reduce input complexity, or use callback mode
`Unknown error`	Upstream service returned an unmapped error	Retry with backoff or contact support with the `taskId`

Common request issues

Symptom	Likely cause	Fix
`mode` is rejected	The mode is missing or not one of the four supported values	Use `standard-image-to-video`, `pro-image-to-video`, `master-text-to-video`, or `master-image-to-video`
Text-to-video rejects `image_urls`	`master-text-to-video` does not allow reference images	Remove `image_urls`
Image-to-video rejects the request	Required image is missing or too many images were sent	Send exactly 1 image for standard/master image modes, or 1-2 images for pro mode
`aspect_ratio` appears ignored	The field only applies to `master-text-to-video`	Use `master-text-to-video` when aspect ratio control is required
Image URL fails before generation	The backend validates public URL reachability	Use a direct, reachable HTTP(S) URL and avoid private or localhost links

See Error Codes for the full error reference.

Getting Started

Image Models

Video Models

Audio Models

Overview

Endpoint and authentication

Copy-paste async quickstart

Poll for result

Request body

Standard image-to-video

Pro image-to-video

Master text-to-video

Master image-to-video

Parameters

Response format

Submit task response

Status response fields

Webhook callback mode

Billing

Latency and polling

Errors and troubleshooting

HTTP errors

Task failure codes

Common request issues

Getting Started

Image Models

Video Models

Audio Models

Documentation Index

​Overview

​Endpoint and authentication

​Copy-paste async quickstart

​Poll for result

​Request body

​Standard image-to-video

​Pro image-to-video

​Master text-to-video

​Master image-to-video

​Parameters

​Response format

​Submit task response

​Status response fields

​Webhook callback mode

​Billing

​Latency and polling

​Errors and troubleshooting

​HTTP errors

​Task failure codes

​Common request issues

​Related links

Overview

Endpoint and authentication

Copy-paste async quickstart

Poll for result

Request body

Standard image-to-video

Pro image-to-video

Master text-to-video

Master image-to-video

Parameters

Response format

Submit task response

Status response fields

Webhook callback mode

Billing

Latency and polling

Errors and troubleshooting

HTTP errors

Task failure codes

Common request issues

Related links