MODEL ID bfl:6@1

live

FLUX.2 [flex]

by Black Forest Labs November 25, 2025

FLUX.2 [flex] is a configurable text to image and image editing model built for precise text placement and stable layouts. It exposes sampling and guidance controls and supports up to ten reference images for consistent characters or products across complex compositions.

API Options

Platform-level options for task execution and delivery.

taskType string required value: imageInference: Identifier for the type of task being performed

taskUUID string required UUID v4: UUID v4 identifier for tracking tasks and matching async responses. Must be unique per task.

outputType string default: URL: Image output type.

Allowed values 3 values

outputFormat string default: JPG

Specifies the file format of the generated output. The available values depend on the task type and the specific model's capabilities.

`JPG`: Best for photorealistic images with smaller file sizes (no transparency).
`PNG`: Lossless compression, supports high quality and transparency (alpha channel).
`WEBP`: Modern format providing superior compression and transparency support.

**Transparency**: If you are using features like background removal or LayerDiffuse that require transparency, you must select a format that supports an alpha channel (e.g., `PNG`, `WEBP`, `TIFF`). `JPG` does not support transparency.

Allowed values 3 values

outputQuality integer min: 20 max: 99 default: 95: Compression quality of the output. Higher values preserve quality but increase file size.

webhookURL string URI

Specifies a webhook URL where JSON responses will be sent via HTTP POST when generation tasks complete. For batch requests with multiple results, each completed item triggers a separate webhook call as it becomes available.

Learn more 1 resource

Webhooks
PLATFORM

deliveryMethod string default: sync

Determines how the API delivers task results.

Allowed values 2 values

: Returns complete results directly in the API response.
: Returns an immediate acknowledgment with the task UUID. Poll for results using getResponse.

Learn more 1 resource

Task Polling
PLATFORM

uploadEndpoint string URI

Specifies a URL where the generated content will be automatically uploaded using the HTTP PUT method. The raw binary data of the media file is sent directly as the request body. For secure uploads to cloud storage, use presigned URLs that include temporary authentication credentials.

Common use cases:

Cloud storage: Upload directly to S3 buckets, Google Cloud Storage, or Azure Blob Storage using presigned URLs.
CDN integration: Upload to content delivery networks for immediate distribution.

// S3 presigned URL for secure upload
https://your-bucket.s3.amazonaws.com/generated/content.mp4?X-Amz-Signature=abc123&X-Amz-Expires=3600

// Google Cloud Storage presigned URL
https://storage.googleapis.com/your-bucket/content.jpg?X-Goog-Signature=xyz789

// Custom storage endpoint
https://storage.example.com/uploads/generated-image.jpg

The content data will be sent as the request body to the specified URL when generation is complete.

safety object

Content safety checking configuration for image generation.

Properties 2 properties

safety » checkContent checkContent boolean default: false: Enable or disable content safety checking. When enabled, defaults to fast mode.

safety » mode mode string default: none

Safety checking mode for image generation.

Allowed values 2 values

: Disables checking.
: Performs a single check.

ttl integer min: 60: Time-to-live (TTL) in seconds for generated content. Only applies when outputType is URL.

includeCost boolean default: false: Include task cost in the response.

numberResults integer min: 1 max: 20 default: 1: Number of results to generate. Each result uses a different seed, producing variations of the same parameters.

Inputs

Input resources for the task (images, audio, etc). These must be nested inside the inputs object.

inputs » referenceImages referenceImages array of strings min items: 1max items: 10: List of reference images (UUID, URL, Data URI, or Base64).

Generation Parameters

Core parameters for controlling the generated content.

model string required value: bfl:6@1

Identifier of the model to use for generation.

Learn more 3 resources

positivePrompt string required min: 1 max: 32000

Text prompt describing elements to include in the generated output.

Learn more 2 resources

width integer required min: 256 max: 2048 step: 16

Width of the generated media in pixels.

Learn more 2 resources

height integer required min: 256 max: 2048 step: 16

Height of the generated media in pixels.

Learn more 2 resources

seed integer min: 0 max: 9223372036854776000

Random seed for reproducible generation. When not provided, a random seed is generated in the unsigned 32-bit range.

Learn more 1 resource

Text To Image: Seed Controlling Randomness Deterministically
GUIDE

steps integer min: 1 max: 50

Total number of denoising steps. Higher values generally produce more detailed results but take longer.

Learn more 1 resource

Text To Image: Steps Trading Quality For Speed
GUIDE

CFGScale float min: 1 max: 20 step: 0.01 default: 2.5

Guidance scale representing how closely the output will resemble the prompt. Higher values produce results more aligned with the prompt.

Learn more 1 resource

Text To Image: Cfg Scale Balancing Creativity And Control
GUIDE

Provider Settings

Parameters specific to this model provider. These must be nested inside the providerSettings.bfl object.

providerSettings » bfl » promptUpsampling promptUpsampling boolean default: false: Enable automatic enhancement and expansion of the input prompt.

providerSettings » bfl » safetyTolerance safetyTolerance integer min: 0 max: 6 default: 2: Tolerance level for content moderation. Lower values are stricter; higher values are more permissive.

taskType string required value: imageInference: Type of the task.

taskUUID string required UUID v4: UUID of the task.

imageUUID string required UUID v4: UUID of the output image.

imageURL string URI: URL of the output image.

imageBase64Data string: Base64-encoded image data.

imageDataURI string URI: Data URI of the output image.

seed integer: The seed used for generation. If none was provided, shows the randomly generated seed.

NSFWContent boolean: Flag indicating if NSFW content was detected.

cost float: Task cost in USD. Present when includeCost is set to true in the request.

Image to Image

Floating Puppet Regatta Tableau

Request

{
  "taskType": "imageInference",
  "taskUUID": "17c1cda6-a7af-4476-a069-e3753eb413f1",
  "model": "bfl:6@1",
  "positivePrompt": "Create a richly detailed airborne regatta above a vast salt flat at golden sunrise, using the reference images to preserve the marionette captain, quilted sail materials, and cloud barge design. Show multiple puppet-crewed vessels drifting in layered formation through bright apricot and pale cyan sky, long reflections shimmering below. The main vessel dominates the foreground with crisp readable painted lettering on the sail: \"SKY HARBOR CUP\". Include smaller banners with clean simple text such as \"HEAT 3\" and \"NORTH WIND\". Emphasize precise composition, stable geometry, handcrafted textures, taut ropes, stitched cloth, varnished wood, tiny brass fittings, and playful theatrical charm. Cinematic wide shot, storybook realism, airy scale, high detail, elegant color harmony, gentle atmosphere, no modern city elements.",
  "width": 1344,
  "height": 768,
  "seed": 77612,
  "steps": 32,
  "CFGScale": 3.5,
  "providerSettings": {
    "bfl": {
      "promptUpsampling": true,
      "safetyTolerance": 2
    }
  },
  "inputs": {
    "referenceImages": [
      "https://assets.runware.ai/assets/inputs/17078c68-3b4f-46af-ab45-fdc8f39a2cc1.jpg",
      "https://assets.runware.ai/assets/inputs/d0d1a087-bbab-4a75-9025-ac01bbcdf610.jpg",
      "https://assets.runware.ai/assets/inputs/d367c73d-617c-444c-b902-fa61d7cffc78.jpg"
    ]
  }
}

Response

{
  "taskType": "imageInference",
  "taskUUID": "17c1cda6-a7af-4476-a069-e3753eb413f1",
  "imageUUID": "3c21742a-4414-444a-8562-a40e0a90bdac",
  "imageURL": "https://im.runware.ai/image/os/a14d18/ws/2/ii/3c21742a-4414-444a-8562-a40e0a90bdac.jpg",
  "seed": 77612,
  "cost": 0.24
}

Image to Image

Glasshouse Automaton Floristry Display

Request

{
  "taskType": "imageInference",
  "taskUUID": "2ff8ac6e-fd1d-44fe-a79e-5e371798996d",
  "model": "bfl:6@1",
  "positivePrompt": "Create a whimsical late-afternoon glasshouse scene centered on an elegant brass automaton florist arranging rare blooms on a long wooden counter. Use the reference images to keep the machine design, greenhouse structure, and plant palette consistent. The composition should feel airy and meticulously organized, with hanging ferns, fogged glass panes, tiled flooring, labeled drawers, bundles of stems, and polished tools. Include a small hand-painted shop sign with clear readable text: \"VERDANT CLOCKWORK BLOOMS\". Refined cinematic realism, intricate materials, stable geometry, balanced depth, warm sunlight diffused through glass, crisp focus on the central display, charming invention and quiet wonder.",
  "width": 1280,
  "height": 768,
  "seed": 6530,
  "steps": 32,
  "CFGScale": 3.5,
  "providerSettings": {
    "bfl": {
      "promptUpsampling": true,
      "safetyTolerance": 2
    }
  },
  "inputs": {
    "referenceImages": [
      "https://assets.runware.ai/assets/inputs/56fd0fc2-71c5-4e8b-8bd9-f3b251742d8c.jpg",
      "https://assets.runware.ai/assets/inputs/012f7433-d4fa-4a2d-aa59-9a887c0bac05.jpg",
      "https://assets.runware.ai/assets/inputs/6c3ab5a1-be16-40c8-a4d4-98fa31be2339.jpg"
    ]
  }
}

Response

{
  "taskType": "imageInference",
  "taskUUID": "2ff8ac6e-fd1d-44fe-a79e-5e371798996d",
  "imageUUID": "5b8f76c5-2db7-4f90-b220-fb1ba9c77894",
  "imageURL": "https://im.runware.ai/image/os/a08d21/ws/2/ii/5b8f76c5-2db7-4f90-b220-fb1ba9c77894.jpg",
  "seed": 6530,
  "cost": 0.24
}