Edit images using Flux models

June 3, 2025

Table of contents

  1. Request Headers
  2. Request Body
  3. Responses
  4. Model
  5. Examples
  6. Try It

This endpoint edits existing images using FLUX.1 Kontext model based on text prompts and reference images.

https://api.useapi.net/v1/ltxstudio/images/flux-edit

Request Headers 
Authorization: Bearer {API token}
Content-Type: application/json
# Alternatively you can use multipart/form-data
# Content-Type: multipart/form-data
Request Body 
{
  "prompt": "Add golden sunset lighting to the landscape",
  "referenceAssetId": "asset:3b18…-type:image/png",
  "aspectRatio": "16:9",
  "seed": 123456
}
  • email is optional when only one account configured.
    However, if you have multiple accounts configured, this parameter becomes required.
  • prompt is required, text description for image editing (max 2000 characters)
  • referenceAssetId is required, asset ID for the source image to edit (use field fileId from POST /assets/?type=reference-image)
  • aspectRatio is optional, output image aspect ratio.
    Supported values: 16:9, 9:16, 1:1.
    Default is 16:9.
  • seed is optional, random seed for reproducible results.
    Default is random.
  • pollForResult is optional, number of polling attempts to wait for completion (each attempt waits 3 seconds, up to 60 seconds total max) before sending job to the scheduler.
    For example, pollForResult: 5 will poll every 3 seconds for up to 15 seconds total.
    Supported values: 1-20.
    Default is immediate return with jobId.
  • maxJobs is optional, override the default maximum number of concurrent jobs.
  • replyUrl is optional, webhook URL for job completion notifications.
    See GET assets/jobId for response model.
  • replyRef is optional, custom reference for webhook identification.
Responses

  • 200 OK (Job Created)

    {
    "jobId": "email:[email protected]:7a34b821-9fd0-205e-d21b-4abc6f7839e7-type:image",
    "generationId": "gen_abc123def456"
}

  • 200 OK (pollForResult completed)

    {
    "status": {
        "type": "completed",
        "progress": 100,
        "artifact": {
            "assetUrl": "https://storage.googleapis.com/lt-infinity-prd/artifacts/vertex-ai/…",
            "expirationDateString": "1748919477350",
            "asset": {
                "type": "artifact",
                "fileId": "asset:3b18…-type:image/png",
                "mimeType": "image/png",
                "artifactSubtype": "vertex-ai"
            }
        }
    },
    "jobId": "email:[email protected]:7a34b821-9fd0-205e-d21b-4abc6f7839e7-type:image",
    "replyRef": "custom-reference-123",
    "replyUrl": "https://webhook.example.com/ltx-callback",
    "code": 200
}

  • 400 Bad Request

    {
  "error": "Error message",
  "code": 400
}

  • 401 Unauthorized

    {
  "error": "Unauthorized",
  "code": 401
}

  • 402 Payment Required

    {
  "error": "Insufficient credits",
  "code": 402
}
Model

Use GET assets/jobId to retrieve job status and results if they were not provided with the response.

{ // TypeScript, all fields are optional
    status: {
        type: 'active' | 'completed' | 'failed'
        progress?: number
        message?: string
        artifact?: {
            assetUrl: string
            expirationDateString: string
            asset: {
                type: string
                fileId: string
                mimeType: string
                artifactSubtype: string
            }
        }
    }
    jobId?: string
    generationId?: string
    replyRef?: string
    replyUrl?: string
    code?: number
}
Examples 
  • curl "https://api.useapi.net/v1/ltxstudio/images/flux-edit" \
   -H "Authorization: Bearer …" \
   -H "Content-Type: application/json" \
   -d '{
     "prompt": "Add golden sunset lighting to the landscape",
     "referenceAssetId": "asset:3b18…-type:image/png",
     "aspectRatio": "16:9",
     "pollForResult": 10
   }'

  • const token = "API token";
const apiUrl = "https://api.useapi.net/v1/ltxstudio/images/flux-edit";

const response = await fetch(apiUrl, {
  method: "POST",
  headers: {
    "Authorization": `Bearer ${token}`,
    "Content-Type": "application/json",
  },
  body: JSON.stringify({
    "prompt": "Add golden sunset lighting to the landscape",
    "referenceAssetId": "asset:3b18…-type:image/png",
    "aspectRatio": "16:9",
    "pollForResult": 10
  })
});
const result = await response.json();
console.log("response", {response, result});

  • import requests
token = "API token"
apiUrl = "https://api.useapi.net/v1/ltxstudio/images/flux-edit"
headers = {
    "Authorization" : f"Bearer {token}",
    "Content-Type": "application/json"
}
data = {
    "prompt": "Add golden sunset lighting to the landscape",
    "referenceAssetId": "asset:3b18…-type:image/png",
    "aspectRatio": "16:9",
    "pollForResult": 10
}
response = requests.post(apiUrl, headers=headers, json=data)
print(response, response.json())
Try It