Flux Dev

High-quality image generation with exceptional prompt adherence and rich detail.

Flux Dev is Black Forest Labs’ flagship image generation model, optimized for high visual fidelity and detailed outputs. It offers exceptional prompt adherence and produces images with rich detail, making it ideal for production use cases.

Try in playground

Test Flux Dev in the Runpod Hub playground.

Endpoint	https://api.runpod.ai/v2/black-forest-labs-flux-1-dev/runsync
Pricing	$0.02 per megapixel
Type	Image generation

For faster, cheaper generation during development, consider Flux Schnell which is optimized for speed.

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: "28"

Number of denoising steps. Higher values produce more detailed images but take longer. Range: 1-50.

input.guidance · float · default: "7.5"

How closely to follow the prompt. Higher values produce images more faithful to the prompt but may reduce creativity. 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-dev/runsync" \
  -H "Authorization: Bearer $RUNPOD_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "input": {
      "prompt": "A serene mountain landscape at sunset, golden light filtering through clouds, photorealistic",
      "negative_prompt": "blurry, low quality",
      "width": 1024,
      "height": 1024,
      "num_inference_steps": 28,
      "guidance": 7.5,
      "seed": 42,
      "image_format": "png"
    }
  }'

import requests

response = requests.post(
    "https://api.runpod.ai/v2/black-forest-labs-flux-1-dev/runsync",
    headers={
        "Authorization": f"Bearer {RUNPOD_API_KEY}",
        "Content-Type": "application/json",
    },
    json={
        "input": {
            "prompt": "A serene mountain landscape at sunset, golden light filtering through clouds, photorealistic",
            "negative_prompt": "blurry, low quality",
            "width": 1024,
            "height": 1024,
            "num_inference_steps": 28,
            "guidance": 7.5,
            "seed": 42,
            "image_format": "png",
        }
    },
)

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

const response = await fetch(
  "https://api.runpod.ai/v2/black-forest-labs-flux-1-dev/runsync",
  {
    method: "POST",
    headers: {
      "Authorization": `Bearer ${RUNPOD_API_KEY}`,
      "Content-Type": "application/json",
    },
    body: JSON.stringify({
      input: {
        prompt: "A serene mountain landscape at sunset, golden light filtering through clouds, photorealistic",
        negative_prompt: "blurry, low quality",
        width: 1024,
        height: 1024,
        num_inference_steps: 28,
        guidance: 7.5,
        seed: 42,
        image_format: "png",
      },
    }),
  }
);

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": 17,
  "executionTime": 3986,
  "workerId": "oqk7ao1uomckye",
  "output": {
    "image_url": "https://image.runpod.ai/abc123/output.png",
    "cost": 0.02097152
  }
}

{
  "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 Dev charges $0.02 per megapixel. Cost is calculated as: (width × height / 1,000,000) × \$0.02.

Image size	Megapixels	Cost
512×512	0.26 MP	$0.0052
1024×1024	1.05 MP	$0.021
1536×1536	2.36 MP	$0.047