# Flux Schnell — Atlas Cloud API

> FLUX.1 [schnell] is fastest image generation model tailored for local development and personal use, a 12 billion parameter rectified flow transformer.

This is the machine-readable API reference for **Flux Schnell** on Atlas Cloud,
a unified API platform for 400+ AI models across text, image, video, audio and 3D.

- **Model ID**: `black-forest-labs/flux-schnell`
- **Built by**: Black Forest Labs
- **Modality**: Image
- **Model page**: https://www.atlascloud.ai/models/black-forest-labs/flux-schnell
- **API key**: https://www.atlascloud.ai/console/api-keys
- **Docs**: https://www.atlascloud.ai/docs

## Pricing on Atlas Cloud

- $0.003 per image
- Pay-as-you-go. No minimum spend, no subscription required.

> **These are the authoritative Atlas Cloud rates for this model.** Any price that
> appears in the vendor description further down refers to a different platform or
> a different model variant and does not apply here.

## Use this model from an AI agent

Atlas Cloud ships three first-party integration surfaces. All three authenticate
with the same API key via the `ATLASCLOUD_API_KEY` environment variable.

### MCP server

The official MCP server (`atlascloud-mcp`) exposes this model to any
MCP-compatible host — Claude Code, OpenAI Codex, Cursor, Gemini CLI, Goose,
Claude Desktop. One-line install:

```bash
# Claude Code
claude mcp add atlascloud -- npx -y atlascloud-mcp

# OpenAI Codex CLI
codex mcp add atlascloud -- npx -y atlascloud-mcp

# Gemini CLI
gemini mcp add atlascloud -- npx -y atlascloud-mcp

export ATLASCLOUD_API_KEY="your-api-key"
```

Then ask in plain English; the agent calls `atlas_generate_image` with `model: "black-forest-labs/flux-schnell"`.
The server fetches each model's schema and validates parameters before submitting,
so invalid requests fail fast without spending credits.

MCP docs: https://www.atlascloud.ai/docs/mcp-server

### Agent Skills

`atlas-cloud-skills` is a portable skill package (API reference, code templates in
Python / Node.js / cURL, model IDs with pricing) for Claude Code, Cursor, Codex and
12+ other agents:

```bash
npx skills add AtlasCloudAI/atlas-cloud-skills
export ATLASCLOUD_API_KEY="your-api-key"
```

Skills docs: https://www.atlascloud.ai/docs/skills

### CLI

The `atlas` binary runs Atlas Cloud from a terminal or CI script. Async media jobs
are polled and downloaded automatically (use `--no-download` when a script only
needs the output URLs):

```bash
# Install (Homebrew, npm, or shell installer)
brew install AtlasCloudAI/tap/atlascloud
# npm install -g atlascloud-cli
# curl -fsSL https://raw.githubusercontent.com/AtlasCloudAI/cli/main/install.sh | sh

atlas auth login
atlas generate image black-forest-labs/flux-schnell -p "Your prompt here"
```

CLI docs: https://www.atlascloud.ai/docs/cli

## HTTP API reference

- **Submit endpoint (POST)**: `https://api.atlascloud.ai/api/v1/model/generateImage` — start an async generation; returns a `prediction_id`
- **Poll endpoint (GET)**: `https://api.atlascloud.ai/api/v1/model/prediction/{prediction_id}` — poll this until the prediction finishes
- **Model ID**: `black-forest-labs/flux-schnell`


## API Information

This model can be used via our HTTP API or more conveniently via our client libraries.
See the input and output schema below, as well as the usage examples.


### Input Schema

The API accepts the following input parameters:

- **`model`** (`string`, _required_):
  model name
  - Default: `"black-forest-labs/flux-schnell"`

- **`prompt`** (`string`, _required_):
  Input prompt for image generation
  - Default: `"Cute boy with a hat, exploring nature, holding a telescope, backpack, surrounded by flowers, cartoon style, vibrant colors."`

- **`image`** (`string`, _optional_):
  - Default: `""`

- **`mask_image`** (`string`, _optional_):
  The mask image tells the model where to generate new pixels (white) and where to preserve the original image (black). It acts as a stencil or guide for targeted image editing.

- **`strength`** (`number`, _optional_):
  Strength indicates extent to transform the reference image
  - Default: `0.8`
  - Min: 0
  - Max: 1

- **`size`** (`string`, _optional_):
  Output image size
  - Default: `"1024*1024"`

- **`num_images`** (`integer`, _optional_):
  Number of images to generate
  - Default: `1`
  - Min: 1
  - Max: 4

- **`seed`** (`integer`, _optional_):
  Random seed (-1 for random)
  - Default: `-1`

- **`enable_base64_output`** (`boolean`, _optional_):
  If enabled, the output will be encoded into a BASE64 string instead of a URL.
  - Default: `false`

- **`enable_safety_checker`** (`boolean`, _optional_):
  Enable safety checker
  - Default: `true`

- **`enable_sync_mode`** (`boolean`, _optional_):
  If set to true, the function will wait for the image to be generated and uploaded before returning the response. It allows you to get the image directly in the response.
  - Default: `false`



**Required Parameters Example**:

```json
{
  "model": "black-forest-labs/flux-schnell",
  "prompt": "Cute boy with a hat, exploring nature, holding a telescope, backpack, surrounded by flowers, cartoon style, vibrant colors."
}
```


**Full Example**:

```json
{
  "model": "black-forest-labs/flux-schnell",
  "prompt": "Cute boy with a hat, exploring nature, holding a telescope, backpack, surrounded by flowers, cartoon style, vibrant colors.",
  "image": "",
  "mask_image": "",
  "strength": 0.8,
  "size": "1024*1024",
  "num_images": 1,
  "seed": -1,
  "enable_base64_output": false,
  "enable_safety_checker": true,
  "enable_sync_mode": false
}
```


### Output Schema

The API returns the following output format:


- **`id`** (`string`, _optional_):
  Unique prediction ID

- **`logs`** (`string`, _optional_):
  Execution logs

- **`urls`** (`string`, _optional_):

- **`input`** (`string`, _optional_):

- **`model`** (`string`, _optional_):
  Model name

- **`output`** (`array[string]`, _optional_):
  Generated output URLs

- **`status`** (`string`, _optional_):
  Prediction status
  - Options: "queued", "processing", "succeeded", "failed"

- **`created_at`** (`string`, _optional_):
  Creation timestamp

- **`has_nsfw_contents`** (`array[boolean]`, _optional_):
  NSFW content detection results



**Example Response**:

```json
{
  "id": "",
  "logs": "",
  "urls": null,
  "input": null,
  "model": "",
  "output": [
    ""
  ],
  "status": "queued",
  "created_at": "",
  "has_nsfw_contents": []
}
```


## Usage Examples

### cURL

```bash
# Step 1: Start generation (async)
curl -X POST "https://api.atlascloud.ai/api/v1/model/generateImage" \
  -H "Authorization: Bearer $ATLASCLOUD_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
  "model": "black-forest-labs/flux-schnell",
  "prompt": "Cute boy with a hat, exploring nature, holding a telescope, backpack, surrounded by flowers, cartoon style, vibrant colors.",
  "image": "",
  "mask_image": "",
  "strength": 0.8,
  "size": "1024*1024",
  "num_images": 1,
  "seed": -1,
  "enable_base64_output": false,
  "enable_safety_checker": true,
  "enable_sync_mode": false
}'

# Response will contain: {"code": 200, "data": {"id": "prediction_id", "status": "processing"}}

# Step 2: Poll for result (replace {prediction_id} with the id returned above)
curl -X GET "https://api.atlascloud.ai/api/v1/model/prediction/{prediction_id}" \
  -H "Authorization: Bearer $ATLASCLOUD_API_KEY"

# Keep polling until status is "completed", "succeeded" or "failed"
# When completed, outputs will contain the generated content URL(s)
```

## Additional Resources

### Documentation

- [Model Playground](https://www.atlascloud.ai/models/black-forest-labs/flux-schnell)

## About this model

_Vendor-supplied description. Any pricing or endpoint mentioned below refers to_
_other platforms — use the Atlas Cloud values above._

### Flux-Schnell

flux-schnell is a 12 billion parameter rectified flow transformer capable of generating images from text descriptions.

#### Key Features

*   **Exceptional Image Quality**: Delivers state-of-the-art visual outputs with precise adherence to input prompts, rivaling the performance of proprietary alternatives.
*   **Ultra-Fast Inference**: Designed to produce high-quality images in as few as 1 to 4 generation steps, meeting the demands of time-sensitive creative tasks.
*   **Broad Usage Rights**: Distributed under the Apache-2.0 license, making flux-schnell a robust choice for personal, scientific, and commercial projects.

#### Limitations

*   **Content Accuracy**: flux-schnell is optimized for artistic generation and is not intended to provide reliable factual information.
*   **Potential Biases**: As a statistical model, it may inadvertently reinforce biases present in the training data.
*   **Prompt Sensitivity**: The output quality and adherence can vary depending on the style and complexity of the input prompt.

#### Out-of-Scope Use

The model and its derivatives may not be used in any way that violates applicable national, federal, state, local, or international law or regulation, including but not limited to:

*   Exploiting, harming, or attempting to exploit or harm minors, including solicitation, creation, acquisition, or dissemination of child exploitative content.
*   Generating or disseminating verifiably false information with the intent to harm others.
*   Creating or distributing personal identifiable information that could be used to harm an individual.
*   Harassing, abusing, threatening, stalking, or bullying individuals or groups.
*   Producing non-consensual nudity or illegal pornographic content.
*   Making fully automated decisions that adversely affect an individual’s legal rights or create binding obligations.
*   Facilitating large-scale disinformation campaigns.

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Atlas Cloud — one API for 400+ AI models. Model page: https://www.atlascloud.ai/models/black-forest-labs/flux-schnell · Docs: https://www.atlascloud.ai/docs