# FLUX.2 [klein] 9B

> Black Forest Labs' distilled 9 billion parameter image generation model with sub-second inference and multi-reference support

## Quick Reference

- Model ID: flux.2-klein-9b
- Creator: Black Forest Labs
- Status: active
- Family: flux.2
- Base URL: https://api.lumenfall.ai/openai/v1

## Specifications

- Max Resolution: 2048x2048
- Max Input Images: 4
- Input Modalities: text, image
- Output Modalities: image
- Supported Modes: Text to Image, Image Edit

## Model Identifiers

- Primary Slug: flux.2-klein-9b
- Aliases: flux-2-klein-9b


## Tags

image-generation, text-to-image, image-editing, open-weights

## Available Providers

### fal.ai

- Config Key: fal/flux.2-klein-9b
- Provider Model ID: fal-ai/flux-2/klein/9b
- Pricing: $0.0060/megapixel
  - Source: https://fal.ai/models/fal-ai/flux-2/klein/9b

### fal.ai

- Config Key: fal/flux.2-klein-9b-edit
- Provider Model ID: fal-ai/flux-2/klein/9b/edit
- Pricing: $0.011/megapixel, $0.011/megapixel
  - Source: https://fal.ai/models/fal-ai/flux-2/klein/9b/edit

### Replicate

- Config Key: replicate/flux.2-klein-9b
- Provider Model ID: black-forest-labs/flux-2-klein-9b
- Pricing: $0.0020/megapixel, $0.015/megapixel
  - Source: https://replicate.com/black-forest-labs/flux-2-klein-9b


## Performance Metrics

Provider performance over the last 30 days.

### fal

- Median Generation Time (p50): 2701ms
- 95th Percentile Generation Time (p95): 29003ms
- Average Generation Time: 8417ms
- Success Rate: 100.0%
- Total Requests: 16
- Time to First Byte (p50): 2197ms
- Time to First Byte (p95): 27882ms


## Arena Benchmarks

### Pose & Character Mashup

- Elo: 1134
- Record: 2W / 3L / 0T (5 battles)
- Rank: #2 of 14

### Magic Burger Explosion: Fiery Photorealism Challenge

- Elo: 1098
- Record: 3W / 4L / 2T (9 battles)
- Rank: #9 of 18


## Use Cases & Category Performance

### Photorealism (Text-to-Image)

- Rank: #12 of 32
- Elo: 1206
- Record: 3W / 7L / 2T (12 battles)
- Win Rate: 25.0%

### Text Rendering (Text-to-Image)

- Rank: #20 of 30
- Elo: 1194
- Record: 3W / 7L / 2T (12 battles)
- Win Rate: 25.0%

### Product, Branding & Commercial (Text-to-Image)

- Rank: #21 of 26
- Elo: 1135
- Record: 3W / 4L / 2T (9 battles)
- Win Rate: 33.3%


## Image Gallery

6 images available for this model. Browse all at https://lumenfall.ai/models/black-forest-labs/flux.2-klein-9b/gallery

### Curated Examples

- [Cinematic wide shot of a sophisticated, high-end boutique storefront at dusk. The shop window is ...](https://assets.lumenfall.ai/21DXmWV9AX_Gf751UclKPTkkH_nCCINAi6JWjcUhmq4/rs:fit:1500:1500/plain/gs://lumenfall-prod-assets/n4y1vvhfakobbard923hz6liyh77@jpeg)
- [A high-end cinematic close-up of a vintage 1950s camera lens reflecting a sun-drenched Italian co...](https://assets.lumenfall.ai/PkiWHEdS26cHPcm_9yBpaSXH5RgnEENPopBomEl3mGI/rs:fit:1500:1500/plain/gs://lumenfall-prod-assets/z89mwfn35gzu0t4suxdnrn2korop@jpeg)
- [A hyper-realistic close-up of a weathered, vintage leather traveler's journal resting on a rustic...](https://assets.lumenfall.ai/qRBEPxku-A9MCAVoUgfrTW5esYaEyswBF4OcgTtQRks/rs:fit:1500:1500/plain/gs://lumenfall-prod-assets/9otlhkaizlrav8xejgv4qnn4kicw@jpeg)
- [A vintage wooden storefront for a bookstore called "THE TURNING PAGE" in crisp, elegant gold lett...](https://assets.lumenfall.ai/4NzFv1G_l8dxmIcKx501bL3VghvNWgwpX76A55jFdYY/rs:fit:1500:1500/plain/gs://lumenfall-prod-assets/pss6bd98sdf711lsyi5vu0d5ilfz@jpeg)

### Arena Competition Results

- [Pose & Character Mashup](https://assets.lumenfall.ai/_8_giA4GhBmOd0y4BDYWBdnBu3AHJ236Vf-ojNN0bUo/rs:fit:1500:1500/plain/gs://lumenfall-prod-assets/j8xxq29wu8fp4zjg6b52q76pvayt@jpeg): #2 of 14 (Elo 1134)
- [Magic Burger Explosion: Fiery Photorealism Challenge](https://assets.lumenfall.ai/CrmLH_fhypNL3dvWP8JBXRZwLsgXPf5kmk9iGQLbsPk/rs:fit:1500:1500/plain/gs://lumenfall-prod-assets/9s6if1h1wvyr81f8r7wz49oekrcw@jpeg): #9 of 18 (Elo 1098)

## Example Prompt

The following prompt was used to generate an example image in our playground:

A vintage wooden storefront for a bookstore called "THE TURNING PAGE" in crisp, elegant gold lettering on the window. A cozy interior is visible with floor-to-ceiling shelves. On the sidewalk bench, a capybara sits quietly reading a newspaper.

## Code Examples

### Text to Image (/v1/images/generations)

#### cURL

curl -X POST \
  https://api.lumenfall.ai/openai/v1/images/generations \
  -H "Authorization: Bearer $LUMENFALL_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "flux.2-klein-9b",
    "prompt": "",
    "size": "1024x1024"
  }'

# Response:
# { "created": 1234567890, "data": [{ "url": "https://...", "revised_prompt": "..." }] }

#### JavaScript

import OpenAI from 'openai';

const client = new OpenAI({
  apiKey: 'YOUR_API_KEY',
  baseURL: 'https://api.lumenfall.ai/openai/v1'
});

const response = await client.images.generate({
  model: 'flux.2-klein-9b',
  prompt: '',
  size: '1024x1024'
});

// { created: 1234567890, data: [{ url: "https://...", revised_prompt: "..." }] }
console.log(response.data[0].url);

#### Python

from openai import OpenAI

client = OpenAI(
    api_key="YOUR_API_KEY",
    base_url="https://api.lumenfall.ai/openai/v1"
)

response = client.images.generate(
    model="flux.2-klein-9b",
    prompt="",
    size="1024x1024"
)

# { created: 1234567890, data: [{ url: "https://...", revised_prompt: "..." }] }
print(response.data[0].url)

### Image Edit (/v1/images/edits)

#### cURL

curl -X POST \
  https://api.lumenfall.ai/openai/v1/images/edits \
  -H "Authorization: Bearer $LUMENFALL_API_KEY" \
  -F "model=flux.2-klein-9b" \
  -F "image=@source.png" \
  -F "prompt=Add a starry night sky to this image" \
  -F "size=1024x1024"

# Response:
# { "created": 1234567890, "data": [{ "url": "https://...", "revised_prompt": "..." }] }

#### JavaScript

import OpenAI from 'openai';
import fs from 'fs';

const client = new OpenAI({
  apiKey: 'YOUR_API_KEY',
  baseURL: 'https://api.lumenfall.ai/openai/v1'
});

const response = await client.images.edit({
  model: 'flux.2-klein-9b',
  image: fs.createReadStream('source.png'),
  prompt: 'Add a starry night sky to this image',
  size: '1024x1024'
});

// { created: 1234567890, data: [{ url: "https://...", revised_prompt: "..." }] }
console.log(response.data[0].url);

#### Python

from openai import OpenAI

client = OpenAI(
    api_key="YOUR_API_KEY",
    base_url="https://api.lumenfall.ai/openai/v1"
)

response = client.images.edit(
    model="flux.2-klein-9b",
    image=open("source.png", "rb"),
    prompt="Add a starry night sky to this image",
    size="1024x1024"
)

# { created: 1234567890, data: [{ url: "https://...", revised_prompt: "..." }] }
print(response.data[0].url)


## Frequently Asked Questions

### How much does FLUX.2 [klein] 9B cost?

FLUX.2 [klein] 9B starts at $0.006 per image through Lumenfall. Pricing varies by provider. Lumenfall does not add any markup to provider pricing.

### How do I use FLUX.2 [klein] 9B via API?

You can use FLUX.2 [klein] 9B through Lumenfall's OpenAI-compatible API. Send requests to the unified endpoint with model ID "flux.2-klein-9b". Code examples are available in Python, JavaScript, and cURL.

### Which providers offer FLUX.2 [klein] 9B?

FLUX.2 [klein] 9B is available through fal.ai and Replicate on Lumenfall. Lumenfall automatically routes requests to the best available provider.

### What is the maximum resolution for FLUX.2 [klein] 9B?

FLUX.2 [klein] 9B supports images up to 2048x2048 resolution.

## Links

- Model Page: https://lumenfall.ai/models/black-forest-labs/flux.2-klein-9b
- About: https://lumenfall.ai/models/black-forest-labs/flux.2-klein-9b/about
- Providers, Pricing & Performance: https://lumenfall.ai/models/black-forest-labs/flux.2-klein-9b/providers
- API Reference: https://lumenfall.ai/models/black-forest-labs/flux.2-klein-9b/api
- Benchmarks: https://lumenfall.ai/models/black-forest-labs/flux.2-klein-9b/benchmarks
- Use Cases: https://lumenfall.ai/models/black-forest-labs/flux.2-klein-9b/use-cases
- Gallery: https://lumenfall.ai/models/black-forest-labs/flux.2-klein-9b/gallery
- Playground: https://lumenfall.ai/playground?model=flux.2-klein-9b
- API Documentation: https://docs.lumenfall.ai