API method

Vary Region (inpaint) via API

Updated November 4, 2026

Example

There is a dog lying on a couch in the picture. You paint the dog white on a black mask, send the prompt cat, and Midjourney redraws only that area: now it's a cat on the couch, and the rest of the picture stays as it was. It works only on an upscaled image, so the order is imagine, upscale, inpaint.

Request

Base URL is https://api.userapi.ai. Every request needs two headers, api-key and Content-Type: application/json.

{
  "hash": "6794f6ef-866a-4bc3-b0bc-7b28ec010d1b",
  "mask": "UklGRgQoAABXR...",
  "prompt": "a ginger cat sleeping",
  "webhook_url": "https://example.com/inpaint/webhook-url",
  "webhook_type": "progress"
}

Parameters

What comes back

The response is just the task hash, e.g. {"hash": "ed162774-9244-4038-bdf1-801b033809ec"}. The finished task is what you later get from GET /midjourney/v2/status?hash=… or in the webhook:

{
  "account_hash": "a7d44910-88a6-4673-acc8-d60ffc3479a6",
  "hash": "c688a245-3964-4286-9572-d6c7e22f589a",
  "type": "inpaint",
  "progress": 100,
  "status": "done",
  "result": {
    "url": "https://cdn.discordapp.com/...515a41ad678f.png",
    "proxy_url": "https://media.discordapp.net/...515a41ad678f.png",
    "filename": "...-515a41ad678f.png",
    "content_type": "image/png",
    "width": 2048,
    "height": 2048,
    "size": 7003237
  },
  "status_reason": null,
  "created_at": "2006-01-02T15:04:05+00:00"
}

Example with cURL

1. Picture

curl -X POST https://api.userapi.ai/midjourney/v2/imagine \
  -H "Content-Type: application/json" \
  -H "api-key: $USERAPI_KEY" \
  -d '{"prompt": "a dog lying on a cozy couch"}'

2. Upscale

curl "https://api.userapi.ai/midjourney/v2/status?hash=IMAGINE_HASH" \
  -H "api-key: $USERAPI_KEY"

curl -X POST https://api.userapi.ai/midjourney/v2/upscale \
  -H "Content-Type: application/json" \
  -H "api-key: $USERAPI_KEY" \
  -d '{"hash": "IMAGINE_HASH", "choice": 2}'

3. Mask

The size is in result.width and result.height of the upscale task. Black background, white where to redraw, then PNG to base64. A Python example is below.

4. inpaint

curl -X POST https://api.userapi.ai/midjourney/v2/inpaint \
  -H "Content-Type: application/json" \
  -H "api-key: $USERAPI_KEY" \
  -d '{"hash": "UPSCALE_HASH", "mask": "MASK_BASE64", "prompt": "a ginger cat sleeping"}'

Wrappers for Python, Node.js and PHP are on separate pages. If you'd rather not write code, the same methods are available in n8n and Make. This method in the documentation.

Mask in Python

# pip install pillow
import base64, io
from PIL import Image, ImageDraw

# take these from the upscale result: result.width, result.height
width, height = 1024, 1024
mask = Image.new("L", (width, height), 0)              # black: keep
ImageDraw.Draw(mask).rectangle((300, 420, 760, 900), fill=255)  # white: redraw

buf = io.BytesIO()
mask.save(buf, format="PNG")
mask_b64 = base64.b64encode(buf.getvalue()).decode()

Other methods