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POST
/
v1
/
upload-paint
Advanced Edit with Canvas
curl --request POST \
  --url https://api.legnext.ai/api/v1/upload-paint \
  --header 'Content-Type: multipart/form-data' \
  --header 'x-api-key: <api-key>' \
  --form 'imgUrl=<string>' \
  --form 'canvas={
  "width": 123,
  "height": 123
}' \
  --form 'imgPos={
  "width": 123,
  "height": 123,
  "x": 123,
  "y": 123
}' \
  --form 'mask={
  "areas": [
    {
      "width": 2298,
      "height": 2298,
      "points": [
        123
      ]
    }
  ],
  "url": "<string>"
}' \
  --form 'remixPrompt=<string>' \
  --form 'callback=<string>'
Perform advanced image editing operations using custom uploaded images with precise mask control and canvas positioning.

​
Endpoint

POST https://api.legnext.ai/api/v1/upload-paint

​
Headers

HeaderTypeRequiredDescription
x-api-keystringYesYour API key

​
Request Body

ParameterTypeRequiredDescription
imgUrlstringYesURL of the source image (max length: 1024 characters)
canvasCanvasYesTarget canvas dimensions
imgPosCanvasImgYesImage position and size on canvas
remixPromptstringYesText prompt for the editing operation
maskMaskYesAreas to edit on the original image
callbackstringNoCallback URL for task completion notifications

​
Data Types

​
Canvas

FieldTypeDescription
widthintegerCanvas width in pixels
heightintegerCanvas height in pixels

​
CanvasImg

FieldTypeDescription
widthintegerImage width in pixels
heightintegerImage height in pixels
xintegerHorizontal offset from canvas top-left
yintegerVertical offset from canvas top-left

​
Mask

FieldTypeDescription
areasPolygon[]Polygonal areas to edit (optional)
urlstringBlack and white mask image URL (optional)

​
Polygon

FieldTypeDescription
widthintegerImage width in pixels (500-4096)
heightintegerImage height in pixels (500-4096)
pointsinteger[]Polygon coordinates in XYXY format, clockwise from top-left

​
Example Request

curl -X POST "https://api.legnext.ai/api/v1/upload-paint" \
  -H "x-api-key: YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "imgUrl": "https://cdn.legnext.ai/mj/ba5d06e1-5078-4465-adc1-a4264ecdfac7_0.png",
    "canvas": {
        "width": 1024,
        "height": 1024
    },
    "imgPos": {
        "width": 512,
        "height": 512,
        "x": 256,
        "y": 256
    },
    "mask": {
        "areas": [
            {
                "width": 500,
                "height": 500,
                "points": [
                    10,
                    10,
                    10,
                    100,
                    100,
                    100,
                    100,
                    10
                ]
            }
        ]
    },
    "remixPrompt": "A beautiful mountain scene with trees",
    "callback": "https://webhook.site/d0ca59bc-35a6-4a1e-b1b1-aea7faeb7f67"
  }'

​
Response

Returns a task object containing the task information. 
{
    "job_id": "aa7bd9d9-e20d-408d-b031-46cde06ee888",
    "model": "midjourney",
    "task_type": "upload_paint",
    "status": "completed",
    "config": {
        "service_mode": "public",
        "webhook_config": {
            "endpoint": "https://webhook.site/d0ca59bc-35a6-4a1e-b1b1-aea7faeb7f67",
            "secret": ""
        }
    },
    "input": null,
    "output": {
        "image_url": "https://cdn.legnext.ai/mj/aa7bd9d9-e20d-408d-b031-46cde06ee888_grid.png",
        "image_urls": [
            "",
            "https://cdn.legnext.ai/temp/1760683054288.png",
            "https://cdn.legnext.ai/temp/1760683054157.png",
            "https://cdn.legnext.ai/temp/1760683054555.png"
        ],
        "seed": "647656403",
        "available_actions": {
            "edit": [
                0,
                1,
                2,
                3
            ],
            "inpaint": [
                0,
                1,
                2,
                3
            ],
            "outpaint": [
                0,
                1,
                2,
                3
            ],
            "pan": [
                0,
                1,
                2,
                3
            ],
            "remix": [
                0,
                1,
                2,
                3
            ],
            "reroll": true,
            "upscale": [
                0,
                1,
                2,
                3
            ],
            "variation": [
                0,
                1,
                2,
                3
            ]
        }
    },
    "meta": {
        "created_at": "2025-10-17T06:37:11Z",
        "started_at": "2025-10-17T06:37:11Z",
        "ended_at": "2025-10-17T06:37:41Z",
        "usage": {
            "type": "point",
            "frozen": 120,
            "consume": 120
        }
    },
    "detail": null,
    "logs": [
        "task aa7bd9d9-e20d-408d-b031-46cde06ee888 0 failed"
    ],
    "error": {
        "code": 0,
        "raw_message": "",
        "message": "",
        "detail": null
    }
}

Authorizations

​
x-api-key
string
header
required

API key for authentication

Body

multipart/form-data
​
imgUrl
string<uri>
required

URL of the source image

Maximum string length: 1024
​
canvas
object
required

Target canvas dimensions

​
imgPos
object
required

Image position relative to canvas

​
mask
object
required

Areas to edit on the original image

​
remixPrompt
string
required

Text prompt for the editing operation

Required string length: 1 - 8192
​
callback
string<uri>

Callback URL for task completion notifications

Response

200

Upload paint task created successfully