FLUX 3 Image Generation

Request example

curl --request POST \
  --url https://api.openveer.com/v1/images/generations \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '{
    "model": "flux-3-image",
    "prompt": "Ultra-wide cinematic shot of a fog-drenched coastal highway at dawn, a single vintage car with headlights on",
    "aspect_ratio": "21:9",
    "resolution": "2k"
  }'

import requests

response = requests.post(
    "https://api.openveer.com/v1/images/generations",
    headers={"Authorization": "Bearer <token>"},
    json={
        "model": "flux-3-image",
        "prompt": "Ultra-wide cinematic shot of a fog-drenched coastal highway at dawn, a single vintage car with headlights on",
        "aspect_ratio": "21:9",
        "resolution": "2k"
    }
)
print(response.json())

const response = await fetch("https://api.openveer.com/v1/images/generations", {
  method: "POST",
  headers: {
    Authorization: "Bearer <token>",
    "Content-Type": "application/json"
  },
  body: JSON.stringify({
    model: "flux-3-image",
    prompt: "Ultra-wide cinematic shot of a fog-drenched coastal highway at dawn, a single vintage car with headlights on",
    aspect_ratio: "21:9",
    resolution: "2k"
  })
});
console.log(await response.json());

Response example

{
  "code": 200,
  "data": [
    {
      "status": "submitted",
      "task_id": "task_01K..."
    }
  ]
}

Request headers

Request parameters

Unsupported parameters

The following parameters return HTTP 400 when provided; they are not silently ignored:

• width, height
• Pixel dimensions in size, such as 1024x1024
• seed, steps, guidance
• output_format, negative_prompt, prompt_upsampling, mask_url

Use resolution for higher resolution and aspect_ratio for a specific aspect ratio.

Edit a reference image

{
  "model": "flux-3-image",
  "prompt": "Make the car in the image red while preserving the original road, background, and lighting",
  "image_urls": ["https://example.com/car.jpg"],
  "aspect_ratio": "auto",
  "resolution": "2k"
}

Replace the example URL with a publicly accessible image URL. For multiple references, provide multiple URLs in image_urls, up to 10 images in total.

Multiple reference images

Editing, local editing, and layout use the same endpoint and model on this page, billed by resolution. References are numbered in order: ref_image_0 for the first, ref_image_1 for the second. You can also use Image 1 / Image 2 in the prompt.

{
  "model": "flux-3-image",
  "prompt": "Turn Image 1 into the style of Image 2.",
  "image_urls": [
    "https://example.com/subject.jpg",
    "https://example.com/style.jpg"
  ],
  "aspect_ratio": "auto"
}

Local editing (bounding box)

Start prompt with natural-language editing instructions and refer to elements using <tags>, such as <car_1>. Append a JSON array within the same string, with one object per box. The bbox is not a separate request parameter.

All box fields (src_bbox, tgt_bbox, bbox) use [top, left, bottom, right], that is, [y1, x1, y2, x2], on a 0–1000 normalized grid: top-left is [0,0] and bottom-right is [1000,1000]. These are not pixel coordinates.

This example turns the boxed car red and describes the background to preserve. The URL and box positions are illustrative; replace them to match your image.

{
  "model": "flux-3-image",
  "prompt": "In <ref_image_0>, make the car <car_1> red and preserve the background <background_1>. [{\"id\":\"car_1\",\"from\":null,\"src_bbox\":null,\"tgt_bbox\":[250,300,750,800],\"desc\":\"A red car, preserving its original shape and orientation.\"},{\"id\":\"background_1\",\"from\":\"ref_image_0\",\"src_bbox\":[0,0,1000,1000],\"tgt_bbox\":[0,0,1000,1000],\"desc\":\"Preserve the original road, background, and lighting.\"}]",
  "image_urls": [
    "https://example.com/car.jpg"
  ],
  "aspect_ratio": "auto",
  "resolution": "2k"
}

Move an element

Place the following object in the bbox array at the end of the prompt. from identifies the source image, src_bbox the original position, and tgt_bbox the new position. Also use the matching <knight_1> tag in the natural-language instruction.

{
  "id": "knight_1",
  "from": "ref_image_0",
  "src_bbox": [
    500,
    150,
    850,
    350
  ],
  "tgt_bbox": [
    194,
    55,
    544,
    255
  ],
  "desc": "A miniature grey amigurumi knight figure."
}

Text-to-image layout

Layouts also work without reference images. Each box uses id, bbox, and desc. Set aspect_ratio explicitly because the coordinate grid stretches with the aspect ratio.

{
  "model": "flux-3-image",
  "aspect_ratio": "1:1",
  "prompt": "Minimalist illustration of a black running silhouette <silhouette_1> against a solid chartreuse background <background_1>. [{\"id\":\"background_1\",\"bbox\":[0,0,1000,1000],\"desc\":\"A neon yellow-green background with subtle paper texture.\"},{\"id\":\"silhouette_1\",\"bbox\":[150,150,850,850],\"desc\":\"A black running silhouette with a stippled texture.\"}]"
}

Usage notes

• The bbox JSON is part of the prompt string. When writing request JSON manually, escape its internal double quotes as \". SDKs or JSON serialization methods can handle this automatically.

• Also list regions that should remain unchanged and describe what to preserve in desc.

• Element tags in the prompt must match JSON id values one-to-one. Reference identifiers such as <ref_image_0> point to input images.

• This model has no mask parameter and does not support mask_url; providing mask_url returns HTTP 400. Bbox editing does not use a mask upload parameter.

Submission response

Query task results

curl --request GET \
  --url https://api.openveer.com/v1/tasks/task_01K... \
  --header 'Authorization: Bearer <token>'

Example success response (the image URL is a placeholder):

{
  "code": 200,
  "data": {
    "status": "completed",
    "result": {
      "images": [
        {
          "url": ["https://example.com/generated-image.jpg"]
        }
      ]
    }
  }
}

Read image links from the data.result.images[0].url array. If the task status is failed, inspect the returned error message instead of continuing to wait for an image.

Resolution and billing

Billed per image. The unit price depends only on resolution, not the aspect ratio or number of reference images. Reference images incur no extra charge.

Output sizes are approximate; actual pixel dimensions depend on the returned image. Refer to model pricing for each tier.

Tasks that fail or are blocked by content moderation receive a full refund.

Common parameter errors

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