---
title: FLUX.1 [schnell] | Runware Docs
url: https://runware.ai/docs/models/bfl-flux-1-schnell
description: Ultra fast FLUX.1 text to image model for local use
---
# FLUX.1 [schnell]

![FLUX.1 [schnell]](https://assets.runware.ai/covers/bfl-flux-1-schnell.jpg)

FLUX.1 [schnell] is an open source text to image model from Black Forest Labs. It uses 4 step distillation for very fast generation with strong visual quality. Ideal for local deployment, rapid prototyping, batch image production, and integration into custom creative pipelines.

- **Status**: live
- **ID**: `runware:100@1`
- Try in Playground
- **Creator**: Black Forest Labs
- **Release Date**: August 1, 2024
- **Zero Data Retention**: Yes
- **Capabilities**: Text to Image, Image to Image, Checkpoint

## Pricing

$0.0006 from, per run · ~4s per request

**Measured runs**

- 512x512 · 4 steps: `$0.0006`
- 512x512 · 4 steps +1 LoRA: `$0.0006`
- 1024x1024 · 4 steps: `$0.0013`
- 1024x1024 · 4 steps +2 LoRAs: `$0.0013`

**4 example generations**

- [inpaint](https://runware.ai/docs/models/bfl-flux-1-schnell/examples#example-forensic-botany-book-cover) · 1024×1024: `$0.0006` (~4s)
- [text-to-image](https://runware.ai/docs/models/bfl-flux-1-schnell/examples#example-rooftop-beekeeper-editorial-headshot) · 720p: `$0.0006` (~1s)
- [image-to-image](https://runware.ai/docs/models/bfl-flux-1-schnell/examples#example-modernist-lido-fundraiser-invitation) · 1024×768: `$0.0006` (~4s)
- [expand](https://runware.ai/docs/models/bfl-flux-1-schnell/examples#example-danube-delta-tourism-campaign-panorama) · 1536×1024: `$0.0013` (~15s)

billed by compute time, so a request costs what it took · times vary, measured end to end · [How pricing works](https://runware.ai/docs/models-api/pricing)

## Compatibility & Validation

When `strength` or `inputs.maskImage` is provided, `inputs.seedImage` is required.

---

`width` and `height` must be used together.

## Request Parameters

**API Options**

Platform-level options for task execution and delivery.

### [taskType](https://runware.ai/docs/models/bfl-flux-1-schnell#request-tasktype)

- **Type**: `string`
- **Required**: true
- **Value**: `imageInference`

Identifier for the type of task being performed.

### [taskUUID](https://runware.ai/docs/models/bfl-flux-1-schnell#request-taskuuid)

- **Type**: `string`
- **Required**: true
- **Format**: `UUID v4`

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

### [outputType](https://runware.ai/docs/models/bfl-flux-1-schnell#request-outputtype)

- **Type**: `string`
- **Default**: `URL`

Image output type.

**Allowed values**: `URL` `base64Data` `dataURI`

### [outputFormat](https://runware.ai/docs/models/bfl-flux-1-schnell#request-outputformat)

- **Type**: `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.

> [!NOTE]
> \*\*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**: `JPG` `PNG` `WEBP`

### [outputQuality](https://runware.ai/docs/models/bfl-flux-1-schnell#request-outputquality)

- **Type**: `integer`
- **Min**: `20`
- **Max**: `99`
- **Default**: `95`

Compression quality of the output. Higher values preserve quality but increase file size.

### [webhookURL](https://runware.ai/docs/models/bfl-flux-1-schnell#request-webhookurl)

- **Type**: `string`
- **Format**: `uri`

Webhook URL that receives JSON responses 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](https://runware.ai/docs/models-api/webhooks) (platform)

### [deliveryMethod](https://runware.ai/docs/models/bfl-flux-1-schnell#request-deliverymethod)

- **Type**: `string`
- **Default**: `sync`

Determines how the API delivers task results.

**Allowed values**:

- `sync` Returns complete results directly in the API response.
- `async` Returns an immediate acknowledgment with the task UUID. Poll for results using getResponse.

**Learn more** (1 resource):

- [Task Polling](https://runware.ai/docs/models-api/task-polling) (platform)

### [uploadEndpoint](https://runware.ai/docs/models/bfl-flux-1-schnell#request-uploadendpoint)

- **Type**: `string`
- **Format**: `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.

```text
// 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](https://runware.ai/docs/models/bfl-flux-1-schnell#request-safety)

- **Path**: `safety.checkContent`
- **Type**: `object (1 property)`

Content safety checking configuration for image generation.

#### [checkContent](https://runware.ai/docs/models/bfl-flux-1-schnell#request-safety-checkcontent)

- **Path**: `safety.checkContent`
- **Type**: `boolean`

Enable or disable content safety checking. Increases total generation time.

### [ttl](https://runware.ai/docs/models/bfl-flux-1-schnell#request-ttl)

- **Type**: `integer`
- **Min**: `60`

Time-to-live (TTL) in seconds for generated content. Only applies when `outputType` is `URL`.

### [includeCost](https://runware.ai/docs/models/bfl-flux-1-schnell#request-includecost)

- **Type**: `boolean`

Include task cost in the response.

### [numberResults](https://runware.ai/docs/models/bfl-flux-1-schnell#request-numberresults)

- **Type**: `integer`
- **Min**: `1`
- **Max**: `20`
- **Default**: `1`

Number of results to generate. Each result uses a different seed, producing variations of the same parameters.

### [acceleratorOptions](https://runware.ai/docs/models/bfl-flux-1-schnell#request-acceleratoroptions)

- **Path**: `acceleratorOptions.cacheEndStep`
- **Type**: `object (12 properties)`

Advanced caching mechanisms to speed up generation.

#### [cacheEndStep](https://runware.ai/docs/models/bfl-flux-1-schnell#request-acceleratoroptions-cacheendstep)

- **Path**: `acceleratorOptions.cacheEndStep`
- **Type**: `integer`
- **Min**: `1`

Absolute step number to end caching. Must be greater than `cacheStartStep` and less than or equal to `steps`.

#### [cacheEndStepPercentage](https://runware.ai/docs/models/bfl-flux-1-schnell#request-acceleratoroptions-cacheendsteppercentage)

- **Path**: `acceleratorOptions.cacheEndStepPercentage`
- **Type**: `integer`
- **Min**: `1`
- **Max**: `100`

Percentage of steps to end caching. Alternative to `cacheEndStep`. Must be greater than `cacheStartStepPercentage`.

#### [cacheMaxConsecutiveSteps](https://runware.ai/docs/models/bfl-flux-1-schnell#request-acceleratoroptions-cachemaxconsecutivesteps)

- **Path**: `acceleratorOptions.cacheMaxConsecutiveSteps`
- **Type**: `integer`
- **Min**: `1`
- **Max**: `5`
- **Default**: `3`

Limits the maximum number of consecutive steps that can use cached computations before forcing a fresh computation.

#### [cacheStartStep](https://runware.ai/docs/models/bfl-flux-1-schnell#request-acceleratoroptions-cachestartstep)

- **Path**: `acceleratorOptions.cacheStartStep`
- **Type**: `integer`
- **Min**: `0`

Absolute step number to start caching. Must be less than `cacheEndStep`.

#### [cacheStartStepPercentage](https://runware.ai/docs/models/bfl-flux-1-schnell#request-acceleratoroptions-cachestartsteppercentage)

- **Path**: `acceleratorOptions.cacheStartStepPercentage`
- **Type**: `integer`
- **Min**: `0`
- **Max**: `99`

Percentage of steps to start caching. Alternative to `cacheStartStep`. Must be less than `cacheEndStepPercentage`.

#### [fbCache](https://runware.ai/docs/models/bfl-flux-1-schnell#request-acceleratoroptions-fbcache)

- **Path**: `acceleratorOptions.fbCache`
- **Type**: `boolean`

First Block Cache (FBCache) acceleration. Reuses feature block computations across steps.

#### [fbCacheThreshold](https://runware.ai/docs/models/bfl-flux-1-schnell#request-acceleratoroptions-fbcachethreshold)

- **Path**: `acceleratorOptions.fbCacheThreshold`
- **Type**: `float`
- **Min**: `0`
- **Max**: `1`
- **Step**: `0.01`
- **Default**: `0.25`

Controls the sensitivity threshold for determining when to reuse cached computations. Lower values reuse more aggressively.

#### [teaCache](https://runware.ai/docs/models/bfl-flux-1-schnell#request-acceleratoroptions-teacache)

- **Path**: `acceleratorOptions.teaCache`
- **Type**: `boolean`

TeaCache acceleration for transformer-based models. Estimates step differences to skip redundant computations.

#### [teaCacheDistance](https://runware.ai/docs/models/bfl-flux-1-schnell#request-acceleratoroptions-teacachedistance)

- **Path**: `acceleratorOptions.teaCacheDistance`
- **Type**: `float`
- **Min**: `0`
- **Max**: `1`
- **Step**: `0.01`
- **Default**: `0.5`

Controls the aggressiveness of the TeaCache feature. Lower values prioritize quality, higher values prioritize speed.

#### [dbCache](https://runware.ai/docs/models/bfl-flux-1-schnell#request-acceleratoroptions-dbcache)

- **Path**: `acceleratorOptions.dbCache`
- **Type**: `boolean`

DB Cache (CacheDiT) acceleration. Caches and reuses intermediate transformer block outputs to skip redundant computations.

#### [dbCacheThreshold](https://runware.ai/docs/models/bfl-flux-1-schnell#request-acceleratoroptions-dbcachethreshold)

- **Path**: `acceleratorOptions.dbCacheThreshold`
- **Type**: `float`
- **Min**: `0`
- **Max**: `1`
- **Step**: `0.01`
- **Default**: `0.25`

Controls the sensitivity threshold for DB Cache. Lower values reuse cached blocks more aggressively, higher values prioritize quality.

#### [dbCacheSkipInterval](https://runware.ai/docs/models/bfl-flux-1-schnell#request-acceleratoroptions-dbcacheskipinterval)

- **Path**: `acceleratorOptions.dbCacheSkipInterval`
- **Type**: `integer`
- **Min**: `1`
- **Default**: `5`

Controls how many steps to skip between cache refreshes. Higher values skip more steps for faster generation at the cost of quality.

**Inputs**

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

### [seedImage](https://runware.ai/docs/models/bfl-flux-1-schnell#request-inputs-seedimage)

- **Path**: `inputs.seedImage`
- **Type**: `string`

Image used as a starting point for the generation (UUID, URL, Data URI, or Base64).

**Learn more** (3 resources):

- [Image To Image: Seed Image The Foundation](https://runware.ai/docs/learn/image-to-image#seed-image-the-foundation) (learn)
- [Image Inpainting: Seed And Mask Image The Foundation](https://runware.ai/docs/learn/image-inpainting#seed-and-mask-image-the-foundation) (learn)
- [Image Outpainting: Seed Image The Starting Point](https://runware.ai/docs/learn/image-outpainting#seed-image-the-starting-point) (learn)

### [maskImage](https://runware.ai/docs/models/bfl-flux-1-schnell#request-inputs-maskimage)

- **Path**: `inputs.maskImage`
- **Type**: `string`

Image used to specify which areas of the input image should be edited (UUID, URL, Data URI, or Base64). White marks the area to edit, black is preserved.

**Learn more** (1 resource):

- [Image Inpainting: Seed And Mask Image The Foundation](https://runware.ai/docs/learn/image-inpainting#seed-and-mask-image-the-foundation) (learn)

**Core Parameters**

Primary parameters that define the task output.

### [model](https://runware.ai/docs/models/bfl-flux-1-schnell#request-model)

- **Type**: `string`
- **Required**: true
- **Value**: `runware:100@1`

Identifier of the model to use for generation.

**Learn more** (3 resources):

- [Text To Image: Model Selection](https://runware.ai/docs/learn/text-to-image#model-selection) (learn)
- [Image Inpainting: Model Specialized Inpainting Models](https://runware.ai/docs/learn/image-inpainting#model-specialized-inpainting-models) (learn)
- [Image Outpainting: Other Critical Parameters](https://runware.ai/docs/learn/image-outpainting#other-critical-parameters) (learn)

### [positivePrompt](https://runware.ai/docs/models/bfl-flux-1-schnell#request-positiveprompt)

- **Type**: `string`
- **Required**: true
- **Min**: `2`
- **Max**: `3000`

Text prompt describing elements to include in the generated output.

**Learn more** (1 resource):

- [Prompts](https://runware.ai/docs/learn/prompts) (learn)

### [negativePrompt](https://runware.ai/docs/models/bfl-flux-1-schnell#request-negativeprompt)

- **Type**: `string`
- **Min**: `2`
- **Max**: `3000`

Prompt to guide what to exclude from generation. Ignored when guidance is disabled (CFGScale ≤ 1).

**Learn more** (1 resource):

- [Prompts: Negative Prompts](https://runware.ai/docs/learn/prompts#negative-prompts) (learn)

### [width](https://runware.ai/docs/models/bfl-flux-1-schnell#request-width)

- **Type**: `integer`
- **Required**: true
- **Min**: `128`
- **Max**: `2048`
- **Step**: `64`

Width of the generated media in pixels.

**Learn more** (2 resources):

- [Dimensions](https://runware.ai/docs/learn/dimensions) (learn)
- [Image Outpainting: Dimensions Critical For Outpainting](https://runware.ai/docs/learn/image-outpainting#dimensions-critical-for-outpainting) (learn)

### [height](https://runware.ai/docs/models/bfl-flux-1-schnell#request-height)

- **Type**: `integer`
- **Required**: true
- **Min**: `128`
- **Max**: `2048`
- **Step**: `64`

Height of the generated media in pixels.

**Learn more** (2 resources):

- [Dimensions](https://runware.ai/docs/learn/dimensions) (learn)
- [Image Outpainting: Dimensions Critical For Outpainting](https://runware.ai/docs/learn/image-outpainting#dimensions-critical-for-outpainting) (learn)

### [seed](https://runware.ai/docs/models/bfl-flux-1-schnell#request-seed)

- **Type**: `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):

- [Seed](https://runware.ai/docs/learn/seed) (learn)

### [steps](https://runware.ai/docs/models/bfl-flux-1-schnell#request-steps)

- **Type**: `integer`
- **Min**: `1`
- **Max**: `100`
- **Default**: `4`

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

**Learn more** (1 resource):

- [Steps](https://runware.ai/docs/learn/steps) (learn)

### [scheduler](https://runware.ai/docs/models/bfl-flux-1-schnell#request-scheduler)

- **Type**: `string`

Scheduler to use for the diffusion process.

**Allowed values**: `DDIM` `DDIMScheduler` `DDPMScheduler` `DEISMultistepScheduler` `Default` `DPM++` `DPM++ 2M` `DPM++ 2M Beta` `DPM++ 2M Exponential` `DPM++ 2M Karras` `DPM++ 2M SDE` `DPM++ 2M SDE Beta` `DPM++ 2M SDE Exponential` `DPM++ 2M SDE Karras` `DPM++ 2M SDE Uniform` `DPM++ 2M Uniform` `DPM++ 3M` `DPM++ 3M Beta` `DPM++ 3M Exponential` `DPM++ 3M Karras` `DPM++ 3M SDE Uniform` `DPM++ 3M Uniform` `DPM++ Beta` `DPM++ Exponential` `DPM++ Karras` `DPM++ SDE` `DPM++ SDE Beta` `DPM++ SDE Exponential` `DPM++ SDE Karras` `DPM++ Uniform` `DPM++ Uniform Beta` `DPM++ Uniform Exponential` `DPM++ Uniform Karras` `DPMSolverMultistepInverse` `DPMSolverMultistepScheduler` `DPMSolverSinglestepScheduler` `EDMDPMSolverMultistepScheduler` `EDMEulerScheduler` `Euler` `Euler a` `Euler Beta` `Euler Exponential` `Euler Karras` `EulerAncestralDiscreteScheduler` `EulerDiscreteScheduler` `FlowMatchEulerDiscreteScheduler` `Heun` `HeunDiscreteScheduler` `Heun Karras` `IPNDMScheduler` `IPNDM Uniform` `IPNDM Uniform Beta` `IPNDM Uniform Exponential` `IPNDM Uniform Karras` `KDPM2AncestralDiscreteScheduler` `KDPM2DiscreteScheduler` `LCM` `LCMScheduler` `LMS` `LMSDiscreteScheduler` `LMS Karras` `PNDMScheduler` `TCDScheduler` `UniPC` `UniPC 2M` `UniPC 2M Karras` `UniPC 2M Uniform` `UniPC 3M` `UniPC 3M Karras` `UniPC 3M Uniform` `UniPC Karras` `UniPC Uniform` `UniPC Uniform Beta` `UniPC Uniform Exponential` `UniPC Uniform Karras`

**Learn more** (2 resources):

- [Schedulers](https://runware.ai/docs/learn/schedulers) (learn)
- [Image Outpainting: Other Critical Parameters](https://runware.ai/docs/learn/image-outpainting#other-critical-parameters) (learn)

### [CFGScale](https://runware.ai/docs/models/bfl-flux-1-schnell#request-cfgscale)

- **Type**: `float`
- **Min**: `0`
- **Max**: `20`
- **Step**: `0.01`

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

**Learn more** (1 resource):

- [Cfg Scale](https://runware.ai/docs/learn/cfg-scale) (learn)

### [strength](https://runware.ai/docs/models/bfl-flux-1-schnell#request-strength)

- **Type**: `float`
- **Min**: `0`
- **Max**: `1`
- **Step**: `0.01`
- **Default**: `0.8`

Strength of the transformation. Lower values result in more influence from the original input.

**Learn more** (3 resources):

- [Image To Image: Strength The Transformation Intensity](https://runware.ai/docs/learn/image-to-image#strength-the-transformation-intensity) (learn)
- [Image Inpainting: Strength Controlling Transformation Intensity](https://runware.ai/docs/learn/image-inpainting#strength-controlling-transformation-intensity) (learn)
- [Image Outpainting: Strength Understanding The Critical Threshold](https://runware.ai/docs/learn/image-outpainting#strength-understanding-the-critical-threshold) (learn)

### [maskMargin](https://runware.ai/docs/models/bfl-flux-1-schnell#request-maskmargin)

- **Type**: `integer`
- **Min**: `32`
- **Max**: `128`

Extra context pixels around the masked region during inpainting. The model zooms into the masked area with these additional pixels for better integration.

**Learn more** (1 resource):

- [Image Inpainting: Mask Margin Enhancing Detail](https://runware.ai/docs/learn/image-inpainting#mask-margin-enhancing-detail) (learn)

### [promptWeighting](https://runware.ai/docs/models/bfl-flux-1-schnell#request-promptweighting)

- **Type**: `string`

Defines the syntax to be used for prompt weighting.

Prompt weighting allows you to adjust how strongly different parts of your prompt influence the generated image. Choose between `compel` notation with advanced weighting operations or `sdEmbeds` for simple emphasis adjustments.

**Compel syntax**:

Adds 0.2 seconds to image inference time and incurs additional costs.

When `compel` syntax is selected, you can use the following notation in prompts:

**Weighting**

Syntax: `+` `-` `(word)0.9`

Increase or decrease the attention given to specific words or phrases.

Examples:

- Single words: `small+ dog, pixar style`
- Multiple words: `small dog, (pixar style)-`
- Multiple symbols for more effect: `small+++ dog, pixar style`
- Nested weighting: `(small+ dog)++, pixar style`
- Explicit weight percentage: `small dog, (pixar)1.2 style`

**Blend**

Syntax: `.blend()`

Merge multiple conditioning prompts.

Example: `("small dog", "robot").blend(1, 0.8)`

**Conjunction**

Syntax: `.and()`

Break a prompt into multiple clauses and pass them separately.

Example: `("small dog", "pixar style").and()`

**SdEmbeds syntax**:

When `sdEmbeds` syntax is selected, you can use the following notation in prompts:

**Weighting**

Syntax: `(text)` `(text:number)` `[text]`

Use parentheses `()` to increase attention, square brackets `[]` to decrease it. Add a number after the text to specify a custom multiplier.

Examples:

- Single words: `(small) dog, pixar style`
- Multiple words: `small dog, [pixar style]`
- Higher emphasis: `(small:2.5) dog, pixar style`
- Combined emphasis: `(small dog:1.5), pixar style`

**Allowed values**: `sdEmbeds`

**Learn more** (1 resource):

- [Prompts: Prompt Weighting](https://runware.ai/docs/learn/prompts#prompt-weighting) (learn)

### [outpaint](https://runware.ai/docs/models/bfl-flux-1-schnell#request-outpaint)

- **Path**: `outpaint.top`
- **Type**: `object (5 properties)`

Pixel extensions for each boundary direction of the source image. At least one direction is required.

**Learn more** (1 resource):

- [Image Outpainting: Outpaint Defining The Expansion](https://runware.ai/docs/learn/image-outpainting#outpaint-defining-the-expansion) (learn)

#### [top](https://runware.ai/docs/models/bfl-flux-1-schnell#request-outpaint-top)

- **Path**: `outpaint.top`
- **Type**: `integer`
- **Min**: `0`
- **Step**: `64`

Number of pixels to extend to the top.

#### [bottom](https://runware.ai/docs/models/bfl-flux-1-schnell#request-outpaint-bottom)

- **Path**: `outpaint.bottom`
- **Type**: `integer`
- **Min**: `0`
- **Step**: `64`

Number of pixels to extend to the bottom.

#### [left](https://runware.ai/docs/models/bfl-flux-1-schnell#request-outpaint-left)

- **Path**: `outpaint.left`
- **Type**: `integer`
- **Min**: `0`
- **Step**: `64`

Number of pixels to extend to the left.

#### [right](https://runware.ai/docs/models/bfl-flux-1-schnell#request-outpaint-right)

- **Path**: `outpaint.right`
- **Type**: `integer`
- **Min**: `0`
- **Step**: `64`

Number of pixels to extend to the right.

#### [blur](https://runware.ai/docs/models/bfl-flux-1-schnell#request-outpaint-blur)

- **Path**: `outpaint.blur`
- **Type**: `integer`
- **Min**: `0`
- **Max**: `32`

Amount of blur to apply to the mask edge.

**Learn more** (1 resource):

- [Image Outpainting: Outpaint Defining The Expansion](https://runware.ai/docs/learn/image-outpainting#outpaint-defining-the-expansion) (learn)

### [lora](https://runware.ai/docs/models/bfl-flux-1-schnell#request-lora)

- **Path**: `lora.model`
- **Type**: `array of objects (2 properties)`
- **Min items**: `1`

With LoRA (Low-Rank Adaptation), you can adapt a model to specific styles or features by emphasizing particular aspects of the data. This technique enhances the quality and relevance of generated content and can be especially useful when the output needs to adhere to a specific artistic style or follow particular guidelines.

Multiple LoRA models can be used simultaneously to achieve different adaptation goals.

**Examples**:

```json
"lora": [
  {
    "model": "<lora-model-air>",
    "weight": 0.8
  }
]
```

**Learn more** (1 resource):

- [Loras](https://runware.ai/docs/learn/loras) (learn)

#### [model](https://runware.ai/docs/models/bfl-flux-1-schnell#request-lora-model)

- **Path**: `lora.model`
- **Type**: `string`
- **Required**: true

LoRA model identifier.

#### [weight](https://runware.ai/docs/models/bfl-flux-1-schnell#request-lora-weight)

- **Path**: `lora.weight`
- **Type**: `float`
- **Min**: `-4`
- **Max**: `4`
- **Step**: `0.01`
- **Default**: `1`

Strength of the LoRA influence. A value of 0 means no influence. Higher values increase the influence, and negative values can be used to steer away from the LoRA's style.

### [trueCFGScale](https://runware.ai/docs/models/bfl-flux-1-schnell#request-truecfgscale)

- **Type**: `float`

True Classifier-Free Guidance scale. Higher values increase prompt adherence at the cost of quality.

**Features**

Standalone addons and post-processing features.

### [ultralytics](https://runware.ai/docs/models/bfl-flux-1-schnell#request-ultralytics)

- **Path**: `ultralytics.CFGScale`
- **Type**: `object (9 properties)`

Configuration object for Ultralytics face enhancement during generation. This feature uses face detection and inpainting to improve facial details in the same generation step, without requiring post-processing.

> [!NOTE]
> Face enhancement is available for Stable Diffusion 1.X, SDXL, and FLUX models. The system automatically detects faces and applies targeted refinement to improve quality while maintaining consistency with the overall generation.

#### [CFGScale](https://runware.ai/docs/models/bfl-flux-1-schnell#request-ultralytics-cfgscale)

- **Path**: `ultralytics.CFGScale`
- **Type**: `float`
- **Min**: `0`
- **Max**: `50`
- **Step**: `0.1`
- **Default**: `8`

Face refinement guidance scale.

#### [confidence](https://runware.ai/docs/models/bfl-flux-1-schnell#request-ultralytics-confidence)

- **Path**: `ultralytics.confidence`
- **Type**: `float`
- **Min**: `0`
- **Max**: `1`
- **Step**: `0.01`
- **Default**: `0.9`

Confidence threshold for detection.

#### [inpaintSize](https://runware.ai/docs/models/bfl-flux-1-schnell#request-ultralytics-inpaintsize)

- **Path**: `ultralytics.inpaintSize`
- **Type**: `integer`
- **Min**: `128`
- **Max**: `2048`
- **Default**: `1024`

Image size (in pixels) to use for each inpainting region. YOLO detects faces, crops the region, and scales it to this size before running diffusion. Set so most faces land in the 2–4× range of their original pixel size. Going beyond 8× may degrade identity resemblance.

#### [maskBlur](https://runware.ai/docs/models/bfl-flux-1-schnell#request-ultralytics-maskblur)

- **Path**: `ultralytics.maskBlur`
- **Type**: `integer`
- **Min**: `0`
- **Max**: `100`
- **Default**: `5`

Mask feathering amount. Higher values create softer transitions between the enhanced face region and surrounding areas.

#### [maskPadding](https://runware.ai/docs/models/bfl-flux-1-schnell#request-ultralytics-maskpadding)

- **Path**: `ultralytics.maskPadding`
- **Type**: `integer`
- **Min**: `0`
- **Max**: `20`
- **Default**: `5`

Padding around detected face in pixels. Expands the refinement area to include surrounding context like hair and neck.

#### [negativePrompt](https://runware.ai/docs/models/bfl-flux-1-schnell#request-ultralytics-negativeprompt)

- **Path**: `ultralytics.negativePrompt`
- **Type**: `string`

Negative prompt for detection.

#### [positivePrompt](https://runware.ai/docs/models/bfl-flux-1-schnell#request-ultralytics-positiveprompt)

- **Path**: `ultralytics.positivePrompt`
- **Type**: `string`

Positive prompt for detection.

#### [steps](https://runware.ai/docs/models/bfl-flux-1-schnell#request-ultralytics-steps)

- **Path**: `ultralytics.steps`
- **Type**: `integer`
- **Min**: `1`
- **Max**: `100`
- **Default**: `20`

Number of face refinement steps.

#### [strength](https://runware.ai/docs/models/bfl-flux-1-schnell#request-ultralytics-strength)

- **Path**: `ultralytics.strength`
- **Type**: `float`
- **Max**: `1`
- **Step**: `0.01`
- **Default**: `0.3`

Refinement strength. Lower values preserve more of the original, higher values allow more aggressive reconstruction.

### [hiresFix](https://runware.ai/docs/models/bfl-flux-1-schnell#request-hiresfix)

- **Type**: `boolean | object`

Two-stage generation for improved resolution and detail. The model generates at a lower resolution first, then upscales and refines the result in a second pass. Can be enabled with `true` for default settings, or configured as an object for fine-grained control over the upscaling model, steps, and strength.

When using the object form, the `model` parameter is required. Available upscaling models:

| Model | Name | Upscale Factor |
| --- | --- | --- |
| `runware:504@1` | RealESRGAN\_x4plus | 4x |
| `runware:realesrgan@anime-6b` | RealESRGAN\_x4plus\_anime\_6B | 4x |
| `runware:esrgan@animesharp` | 4x-AnimeSharp | 4x |
| `runware:esrgan@ultrasharp` | 4x-UltraSharp | 4x |

**Simple (boolean)**:

```json
"hiresFix": true
```

**Configured (object)**:

```json
"hiresFix": {
  "model": "runware:esrgan@ultrasharp",
  "steps": 15,
  "strength": 0.6
}
```

**Allowed values**: `true`

### [watermark](https://runware.ai/docs/models/bfl-flux-1-schnell#request-advancedfeatures-watermark)

- **Path**: `advancedFeatures.watermark`
- **Type**: `object (6 properties)`

Configuration object for adding watermarks to generated videos. Watermarks can be applied using either text or image content with customizable positioning and appearance. You must provide either `text` or `image` content for the watermark, but not both.

**Text watermark**:

```json
"advancedFeatures": {
  "watermark": {
    "text": "© 2025 Company",
    "displayPosition": "bottom-right",
    "opacity": 0.6,
    "fontColor": "#ffffff",
    "bgColor": "#000000"
  }
}
```

**Image watermark**:

```json
"advancedFeatures": {
  "watermark": {
    "image": "c64351d5-4c59-42f7-95e1-eace013eddab",
    "displayPosition": "top-left",
    "opacity": 0.6
  }
}
```

**Tiled watermark**:

```json
"advancedFeatures": {
  "watermark": {
    "text": "PREVIEW",
    "tiled": true,
    "opacity": 0.4,
    "fontColor": "#cccccc"
  }
}
```

#### [text](https://runware.ai/docs/models/bfl-flux-1-schnell#request-advancedfeatures-watermark-text)

- **Path**: `advancedFeatures.watermark.text`
- **Type**: `string`
- **Min**: `2`
- **Max**: `32`

Watermark text.

#### [image](https://runware.ai/docs/models/bfl-flux-1-schnell#request-advancedfeatures-watermark-image)

- **Path**: `advancedFeatures.watermark.image`
- **Type**: `string`

Watermark image (UUID, URL, Data URI, or Base64).

#### [displayPosition](https://runware.ai/docs/models/bfl-flux-1-schnell#request-advancedfeatures-watermark-displayposition)

- **Path**: `advancedFeatures.watermark.displayPosition`
- **Type**: `string`

Watermark position.

**Allowed values**: `top-left` `top-center` `top-right` `center-left` `center-center` `center-right` `bottom-left` `bottom-center` `bottom-right` `tiled`

#### [opacity](https://runware.ai/docs/models/bfl-flux-1-schnell#request-advancedfeatures-watermark-opacity)

- **Path**: `advancedFeatures.watermark.opacity`
- **Type**: `float`
- **Min**: `0.1`
- **Max**: `1`
- **Step**: `0.01`

Watermark opacity.

#### [fontColor](https://runware.ai/docs/models/bfl-flux-1-schnell#request-advancedfeatures-watermark-fontcolor)

- **Path**: `advancedFeatures.watermark.fontColor`
- **Type**: `string`

Text color in hex format.

#### [bgColor](https://runware.ai/docs/models/bfl-flux-1-schnell#request-advancedfeatures-watermark-bgcolor)

- **Path**: `advancedFeatures.watermark.bgColor`
- **Type**: `string`

Background color in hex format.

## Response Parameters

### [taskType](https://runware.ai/docs/models/bfl-flux-1-schnell#response-tasktype)

- **Type**: `string`
- **Required**: true
- **Value**: `imageInference`

Identifier for the type of task this response belongs to.

### [taskUUID](https://runware.ai/docs/models/bfl-flux-1-schnell#response-taskuuid)

- **Type**: `string`
- **Required**: true
- **Format**: `UUID v4`

UUID v4 identifier echoed from the original request, used to match async responses to their tasks.

### [imageUUID](https://runware.ai/docs/models/bfl-flux-1-schnell#response-imageuuid)

- **Type**: `string`
- **Required**: true
- **Format**: `UUID v4`

UUID of the output image.

### [imageURL](https://runware.ai/docs/models/bfl-flux-1-schnell#response-imageurl)

- **Type**: `string`
- **Format**: `uri`

URL of the output image.

### [imageBase64Data](https://runware.ai/docs/models/bfl-flux-1-schnell#response-imagebase64data)

- **Type**: `string`

Base64-encoded image data.

### [imageDataURI](https://runware.ai/docs/models/bfl-flux-1-schnell#response-imagedatauri)

- **Type**: `string`
- **Format**: `uri`

Data URI of the output image.

### [seed](https://runware.ai/docs/models/bfl-flux-1-schnell#response-seed)

- **Type**: `integer`

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

### [NSFWContent](https://runware.ai/docs/models/bfl-flux-1-schnell#response-nsfwcontent)

- **Type**: `boolean`

Flag indicating if NSFW content was detected.

### [cost](https://runware.ai/docs/models/bfl-flux-1-schnell#response-cost)

- **Type**: `float`

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

## Examples

### text-to-image (text-to-image)

![Rooftop Beekeeper Editorial Headshot](https://assets.runware.ai/examples/bfl-flux-1-schnell/c57a80aa-3de4-4a5e-be7e-078622d2eced.jpg)

```json
{
  "taskType": "imageInference",
  "taskUUID": "85fb34d5-d5fa-4a0f-8953-807ba850e7e6",
  "model": "runware:100@1",
  "positivePrompt": "Professional editorial environmental headshot of a Korean American woman in her early 50s who runs a commercial rooftop apiary, photographed on a city rooftop beside orderly wooden beehives. Head-and-shoulders framing, subject positioned on the right third and looking directly into the camera with a calm, capable expression. She wears a clean ivory beekeeper jacket with the protective veil folded down around her shoulders, leaving her face completely unobstructed; subtle signs of real outdoor work, natural skin texture, a few silver strands in her short black hair. Powder-blue sky, warm ochre hive boxes and a softly defocused charcoal city skyline create a distinctive restrained palette. A few bees visible in the sunlit air without crowding her face. Crisp late-morning side light softened by thin cloud, gentle catchlights, realistic tonal range, shallow depth of field, premium documentary photography, 85mm portrait-lens character, sharp eyes, authentic facial detail. Wide landscape composition with generous clean negative space on the left for editorial layout flexibility, but no text, logos, watermark or graphic overlay. Polished enough for a trade magazine cover story and company leadership profile, grounded, contemporary, quietly optimistic.",
  "width": 1280,
  "height": 704
}
```

---

### image-to-image (image-to-image)

![Modernist Lido Fundraiser Invitation](https://assets.runware.ai/examples/bfl-flux-1-schnell/4076802e-2504-47fc-b4de-70da77c80bc1.jpg)

```json
{
  "taskType": "imageInference",
  "taskUUID": "228e4d1a-bc7f-47e9-bce4-5b1ab140ad44",
  "model": "runware:100@1",
  "positivePrompt": "Transform the supplied architectural photograph into a finished landscape invitation for a preservation fundraiser. Keep the source image's recognizable symmetrical composition, centered white diving tower, long pool perspective, pavilion silhouettes, and horizon placement. Reinterpret the scene as bold mid-century screen-printed artwork: simplified geometric architecture, flat chlorine blue water, coral-red deck, butter-yellow sky, crisp black shadows, subtle ink grain, slight imperfect color registration, and rhythmic white lane markings leading toward the tower. Integrate elegant, highly legible event typography into the open sky and water without obscuring the architecture. Exact text: “THE LIDO RETURNS” as the large headline, then “A NIGHT FOR MODERNISM”, “SATURDAY 14 JUNE · 7 PM”, and “RESTORATION FUND DINNER & NIGHT SWIM”. Use condensed geometric sans-serif capitals with disciplined 1930s civic-poster spacing. Refined, celebratory, architectural, optimistic, collectible cultural-event invitation. Flat edge-to-edge artwork only, not a photographed card, no envelope, no tabletop mockup, no hands, no logos, no extra text.",
  "width": 1024,
  "height": 768,
  "strength": 0.65,
  "inputs": {
    "seedImage": "https://assets.runware.ai/assets/inputs/f115ef50-9784-4ac0-ab0d-a6d441606a67.jpg"
  }
}
```

---

### inpaint (inpaint)

![Forensic Botany Book Cover](https://assets.runware.ai/examples/bfl-flux-1-schnell/555f0696-451b-4281-a76d-73cc66fbd729.jpg)

```json
{
  "taskType": "imageInference",
  "taskUUID": "616eec68-581f-4e60-afc9-c478270767d2",
  "model": "runware:100@1",
  "positivePrompt": "Create a finished square nonfiction book cover by replacing the entire manila envelope with a transparent archival herbarium case in the same position, scale, overhead perspective, and upper-left lighting. The case contains one beautifully arranged pressed poison-hemlock specimen: slender green-brown stem, delicate white flower umbels, fine roots, and several detached leaves, all scientifically plausible. Include small cream evidence labels, a specimen barcode, red forensic sealing tape, and restrained cataloguing marks inside the case. Preserve the existing oxblood-red background and long hard shadow so the new object feels physically present in the original studio scene. Print the exact title “THE EVIDENCE GARDEN” in large condensed ivory uppercase lettering across the clear case, with “FORENSIC BOTANY AND THE STORIES PLANTS TELL” beneath in small clean uppercase type and “MARA VENN” at the bottom. Sophisticated museum-publication art direction, tactile material detail, precise editorial composition, limited palette of oxblood, ivory, botanical green, and evidence red, intelligent and quietly unsettling mood, premium contemporary book-cover design, no envelope remaining.",
  "width": 1024,
  "height": 1024,
  "strength": 0.8,
  "maskMargin": 64,
  "inputs": {
    "seedImage": "https://assets.runware.ai/assets/inputs/d2d07475-03be-48ab-bfe7-1f0fc92d26fc.jpg",
    "maskImage": "https://assets.runware.ai/assets/inputs/cf8da7b8-d0cd-44a9-b189-1bfb864de6b6.png"
  }
}
```

---

### expand (expand)

![Danube Delta Tourism Campaign Panorama](https://assets.runware.ai/examples/bfl-flux-1-schnell/44022d27-126f-44b1-a1e4-c584d0a29726.jpg)

```json
{
  "taskType": "imageInference",
  "taskUUID": "1c15e94e-4a29-400a-8feb-f204e4e0df7e",
  "model": "runware:100@1",
  "positivePrompt": "Extend the supplied central photograph naturally to the left and right to create a seamless wide tourism campaign panorama. Preserve the existing boat, guide, travelers, poses, scale, lighting, waterline, reflections, reeds, mist and all central content exactly as established; do not redesign, replace, crop or duplicate them. Continue the same Danube Delta channel across both new sides with calm rippled water, layered reed beds, low willow islands and soft atmospheric depth. Add a small distant group of white pelicans gliding on the far-left water and two subtle airborne herons in the far-right sky, correctly scaled and secondary to the boat. Match the pale celadon, warm amber and weathered blue palette, early sunrise direction, realistic haze, lens perspective, fine film grain and premium documentary travel-photography finish. Balanced 3:2 landscape composition with believable ecological detail and generous scenery around the central excursion. Seamless edge transitions, no visible join, no fantasy elements, no signage, no lettering, no logos, no frame.",
  "width": 1536,
  "height": 1024,
  "strength": 0.8,
  "outpaint": {
    "left": 256,
    "right": 256,
    "blur": 16
  },
  "inputs": {
    "seedImage": "https://assets.runware.ai/assets/inputs/86452192-996d-4f29-84e7-f00aa8c38e87.jpg"
  }
}
```