FLUX Kontext API Reference

Overview

Property	Value
Model ID	`flux-kontext`
Type	Text-to-Image, Image-to-Image
Pricing	Pro: $0.03/image · Max: $0.06/image
Average Time	10-15 seconds

Authentication

All API requests require authentication using a Bearer token in the Authorization header:

Authorization: Bearer YOUR_API_KEY

Endpoints

1. Submit Generation Task

POST https://api.apixo.ai/api/v1/generateTask/flux-kontext

2. Query Task Status

GET https://api.apixo.ai/api/v1/statusTask/flux-kontext?taskId={taskId}

Request Parameters

Request Body Structure

{
  "request_type": "async",
  "callback_url": "https://your-server.com/callback",
  "input": {
    "mode": "pro",
    "prompt": "Your image description",
    "aspect_ratio": "16:9",
    ...
  }
}

Top-Level Parameters

Parameter	Type	Required	Description
`request_type`	string	Yes	Request mode: `async` (poll results) or `callback` (webhook notification)
`callback_url`	string	No	Webhook URL for callback mode. Must be publicly accessible
`input`	object	Yes	Generation parameters (see below)

Input Parameters

Parameter	Type	Required	Default	Description
`mode`	string	Yes	-	Quality mode: `pro` ($0.03) or `max` ($0.06)
`prompt`	string	Yes	-	Image description (max 10,000 characters)
`image_url`	string	No	-	Input image URL for image-to-image editing
`aspect_ratio`	string	Yes	`16:9`	Output ratio: `21:9`, `16:9`, `4:3`, `1:1`, `3:4`, `9:16`
`output_format`	string	No	`jpeg`	Output format: `jpeg` or `png`
`promptUpsampling`	boolean	No	`false`	Enable AI prompt enhancement
`enableTranslation`	boolean	No	`true`	Auto-translate non-English prompts
`safetyTolerance`	integer	No	`2`	Content moderation: `0` (strict), `1` (moderate), `2` (balanced)
`watermark`	string	No	-	Custom watermark text
`uploadCn`	boolean	No	`false`	Use China servers (`true`) or international (`false`)

Response Format

Task Submission Response

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

Status Query Response

Processing:

{
  "code": 200,
  "message": "success",
  "data": {
    "taskId": "task_12345678",
    "state": "processing",
    "createTime": 1698765400000
  }
}

Success:

{
  "code": 200,
  "message": "success",
  "data": {
    "taskId": "task_12345678",
    "state": "success",
    "resultJson": "{\"resultUrls\":[\"https://example.com/image.jpg\"]}",
    "costTime": 12000,
    "createTime": 1698765400000,
    "completeTime": 1698765412000
  }
}

Failed:

{
  "code": 200,
  "message": "success",
  "data": {
    "taskId": "task_12345678",
    "state": "failed",
    "failCode": "CONTENT_VIOLATION",
    "failMsg": "Content does not meet safety guidelines",
    "createTime": 1698765400000,
    "completeTime": 1698765412000
  }
}

Response Fields:

Field	Type	Description
`code`	integer	HTTP status code (200 = success)
`data.taskId`	string	Unique task identifier
`data.state`	string	Task state: `pending`, `processing`, `success`, `failed`
`data.resultJson`	string	JSON string with `resultUrls` array (on success)
`data.costTime`	integer	Generation time in milliseconds
`data.failCode`	string	Error code (on failure)
`data.failMsg`	string	Error message (on failure)

Callback Response

When the task is completed, the system will send a POST request to your callBackUrl in the following format:

Success Callback

{
  "code": 200,
  "message": "success",
  "data": {
    "taskId": "task_12345678",
    "state": "success",
    "resultJson": "{\"resultUrls\":[\"https://example.com/result.jpg\"]}",
    "completeTime": 1698765432000,
    "createTime": 1698765400000,
    "costTime": 32000
  }
}

Failure Callback

{
  "code": 400,
  "message": "failed",
  "data": {
    "taskId": "task_12345678",
    "state": "failed",
    "failCode": "CONTENT_VIOLATION",
    "failMsg": "Content does not meet safety guidelines",
    "completeTime": 1698765432000,
    "createTime": 1698765400000,
    "costTime": 32000
  }
}

Quick Start

1. Text-to-Image Generation

curl -X POST https://api.apixo.ai/api/v1/generateTask/flux-kontext \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "request_type": "async",
    "input": {
      "mode": "pro",
      "prompt": "A serene mountain landscape at sunset with vibrant colors",
      "aspect_ratio": "16:9"
    }
  }'

Response:

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

2. Check Task Status

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

Response (Success):

{
  "code": 200,
  "message": "success",
  "data": {
    "taskId": "task_12345678",
    "state": "success",
    "resultJson": "{\"resultUrls\":[\"https://example.com/image.jpg\"]}"
  }
}

3. Image-to-Image Editing

curl -X POST https://api.apixo.ai/api/v1/generateTask/flux-kontext \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "request_type": "async",
    "input": {
      "mode": "pro",
      "prompt": "Transform into a watercolor painting style",
      "image_url": "https://example.com/input.jpg",
      "aspect_ratio": "16:9"
    }
  }'

Best Practices

Request Mode Selection

Mode	Use When
Callback	Production environments with public server endpoints
Async	Client-side apps or when webhook setup is not feasible

Performance Tips

Async Mode: Wait 8-10 seconds before first poll, then poll every 2-3 seconds
Timeout: Set maximum wait time to 2 minutes
Rate Limiting: Avoid excessive concurrent requests
Error Handling: Always check state field and handle failures gracefully

Resource Management

Image URLs may be temporary - download and store important results
Clean up failed tasks appropriately
Log taskId for debugging and support