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FLUX.2 is live! High-fidelity image generation made simple.

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black-forest-labs/

FLUX-2-klein-4b

$0.014

x (width / 1024) x (height / 1024)

The fastest model of the Flux 2 family. Frontier visual intelligence — state-of-the-art image generation and editing from Black Forest Labs

black-forest-labs/FLUX-2-klein-4b cover image

Input

Prompt

text prompt

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Settings

Width

image width in px (Default: 1024, 128 ≤ width ≤ 1920)

Height

image height in px (Default: 1024, 128 ≤ height ≤ 1920)

Seed

random seed, empty means random (Default: empty, 0 ≤ seed < 4294967296)

Safety Tolerance

Tolerance level for input and output moderation. Between 0 and 5, 0 being most strict, 5 being least strict (Default: 2, 0 ≤ safety_tolerance ≤ 5)

Output Format

Output format for the generated image

Please upload an image file

Please upload an image file

Please upload an image file

Please upload an image file

Output

generated image #0
Model Information

FLUX.2 [klein]

FLUX.2 [klein] is our fastest model family — generating and editing (multiple) images in under a second without sacrificing quality. Built for real-time applications, creative iteration, and deployment on consumer hardware.

Key Capabilities

  • Sub-second inference — Generate or edit images under a second on modern hardware
  • Unified generation & editing — Text-to-image, image editing, and multi-reference in one model
  • Runs on consumer GPUs — Klein 4B fits in ~8GB VRAM (RTX 3090/4070 and up)
  • Apache 2.0 on 4B — Open-source, fine-tuning, and customization

The Klein Family

ModelBest For
[klein] 4BMaximum speed
[klein] 9BBest quality-to-latency ratio, production apps

Licensing: 4B models are Apache 2.0. 9B models use the FLUX.2-dev Non-Commercial License.

Text-to-image examples

Example focused on realism t2i-klein-grid

Example focused on output diversity t2i-klein-others

Editing examples

i2i-klein