Flux Schnell

Fast, lightweight image generation optimized for speed and prototyping.

Flux Schnell is Black Forest Labs’ fastest and most lightweight FLUX model, ideal for local development, prototyping, and personal use. It generates images quickly with lower step counts while maintaining good quality.

Try in playground

Test Flux Schnell in the Runpod Hub playground.

Endpoint	https://api.runpod.ai/v2/black-forest-labs-flux-1-schnell/runsync
Pricing	$0.0024 per megapixel
Type	Image generation

Flux Schnell is optimized for speed and works best with lower step counts. For higher fidelity production images, consider Flux Dev.

Request

All parameters are passed within the input object in the request body.

input.prompt · string · required

Text description of the desired image. Be specific and detailed for best results.

input.negative_prompt · string

Elements to exclude from the generated image. Use this to prevent unwanted features or styles.

input.width · integer · default: "1024"

Image width in pixels. Must be divisible by 64. Range: 256-1536.

input.height · integer · default: "1024"

Image height in pixels. Must be divisible by 64. Range: 256-1536.

input.num_inference_steps · integer · default: "4"

Number of denoising steps. Schnell is optimized for low step counts. Range: 1-8.

input.guidance · float · default: "7.5"

How closely to follow the prompt. Higher values produce images more faithful to the prompt. Range: 0.0-10.0.

input.seed · integer · default: "-1"

Seed for reproducible results. Use the same seed with identical parameters to generate the same image. Set to -1 for random.

input.image_format · string · default: "jpeg"

Output image format. Accepts png or jpeg.

cURL

curl -X POST "https://api.runpod.ai/v2/black-forest-labs-flux-1-schnell/runsync" \
  -H "Authorization: Bearer $RUNPOD_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "input": {
      "prompt": "A quick sketch of a mountain landscape",
      "width": 1024,
      "height": 1024,
      "num_inference_steps": 4,
      "guidance": 1.0,
      "seed": 123
    }
  }'

import requests

response = requests.post(
    "https://api.runpod.ai/v2/black-forest-labs-flux-1-schnell/runsync",
    headers={
        "Authorization": f"Bearer {RUNPOD_API_KEY}",
        "Content-Type": "application/json",
    },
    json={
        "input": {
            "prompt": "A quick sketch of a mountain landscape",
            "width": 1024,
            "height": 1024,
            "num_inference_steps": 4,
            "guidance": 1.0,
            "seed": 123,
        }
    },
)

result = response.json()
print(result["output"]["image_url"])

const response = await fetch(
  "https://api.runpod.ai/v2/black-forest-labs-flux-1-schnell/runsync",
  {
    method: "POST",
    headers: {
      Authorization: `Bearer ${RUNPOD_API_KEY}`,
      "Content-Type": "application/json",
    },
    body: JSON.stringify({
      input: {
        prompt: "A quick sketch of a mountain landscape",
        width: 1024,
        height: 1024,
        num_inference_steps: 4,
        guidance: 1.0,
        seed: 123,
      },
    }),
  }
);

const result = await response.json();
console.log(result.output.image_url);

Response

id · string

Unique identifier for the request.

status · string

Request status. Returns COMPLETED on success, FAILED on error.

delayTime · integer

Time in milliseconds the request spent in queue before processing began.

executionTime · integer

Time in milliseconds the model took to generate the image.

workerId · string

Identifier of the worker that processed the request.

output · object

The generation result containing the image URL and cost.

output.image_url · string

URL of the generated image. This URL expires after 7 days.

output.cost · float

Cost of the generation in USD, calculated based on the output megapixels.

200

{
  "id": "sync-a1b2c3d4-e5f6-7890-abcd-ef1234567890-u1",
  "status": "COMPLETED",
  "delayTime": 12,
  "executionTime": 856,
  "workerId": "oqk7ao1uomckye",
  "output": {
    "image_url": "https://image.runpod.ai/abc123/output.png",
    "cost": 0.00251658
  }
}

{
  "id": "sync-a1b2c3d4-e5f6-7890-abcd-ef1234567890-u1",
  "status": "FAILED",
  "error": "Invalid parameter: width must be divisible by 64"
}

Image URLs expire after 7 days. Download and store generated images immediately if you need to keep them.

Cost calculation

Flux Schnell charges $0.0024 per megapixel. Cost is calculated as: (width × height / 1,000,000) × \$0.0024.

Image size	Megapixels	Cost
512×512	0.26 MP	$0.0006
1024×1024	1.05 MP	$0.0025
1536×1536	2.36 MP	$0.0057