As of: 2026-11-13 13:49 CET.
Researched and written by AI agents (Claude Opus 5.5 in Claude Code), with a human editor. How we work: https://postcutoff.com/about/
Canonical page: https://postcutoff.com/m/flux-2-klein/

# FLUX.2 [klein] (4B / 9B)

Black Forest Labs, FLUX.2 family. Status: current. Type: image generation. Released: 2026-01-14.

## How to call it

| Provider | Model id | Endpoint | Docs |
|---|---|---|---|
| BFL API | `flux-2-klein-4b` | https://api.bfl.ai/v1/flux-2-klein-4b | https://docs.bfl.ai/flux_2/flux2_overview |
| BFL API | `flux-2-klein-9b` | https://api.bfl.ai/v1/flux-2-klein-9b | https://docs.bfl.ai/flux_2/flux2_overview |
| Hugging Face |  |  | https://huggingface.co/black-forest-labs/FLUX.2-klein-4B |
| Hugging Face |  |  | https://huggingface.co/black-forest-labs/FLUX.2-klein-9B |

## Pricing

- Per image: $0.014
- Unit as published: per image from (4B; 9B from 0.015; text-to-image and editing)
- Source: https://docs.bfl.ai/quick_start/pricing
- Last checked: 2026-09-29

## Specs

- Input: text, image
- Output: image
- Context window: not published
- Max output: not published
- Open weights: yes
- Licence: apache-2.0 (4B); FLUX Non-Commercial License (9B)

## Where it stands

- Newer image generation models in the registry since its release: 21. The 5 newest:
  - GPT Image 2.6 Flare (2026-11-04) https://postcutoff.com/m/gpt-image-2-6-flare/
  - GPT Image 2.6 Sunburst (2026-11-04) https://postcutoff.com/m/gpt-image-2-6-sunburst/
  - MOSS-Image (2026-10-16) https://postcutoff.com/m/moss-image/
  - FLUX 3 Image Klein (2026-10-15) https://postcutoff.com/m/flux-3-image-klein/
  - Krea 3 (Fast / High / Ultra modes) (2026-10-15) https://postcutoff.com/m/krea-3/
- Before it from Black Forest Labs: FLUX.2 [max] (2025-12) https://postcutoff.com/m/flux-2-max/
- After it from Black Forest Labs: FLUX 3 Image Klein (2026-10-15) https://postcutoff.com/m/flux-3-image-klein/
- Weights are public. Licence: apache-2.0; FLUX Non-Commercial License. See the licence for commercial terms.

## What stands out

- Sub-second generation and editing: Size-distilled FLUX.2 variants aimed at sub-second inference for both text-to-image and editing. Source: https://docs.bfl.ai/flux_2/flux2_overview
- Apache-2.0 open weights (4B): 4B checkpoint is Apache 2.0 - commercially usable open weights; base (undistilled) checkpoints published for fine-tuning/LoRA training. Source: https://huggingface.co/black-forest-labs/FLUX.2-klein-4B
- KV-cached 9B variant (found after launch): flux-2-klein-9b-preview / FLUX.2-klein-9b-kv (Mar 2026) add KV caching for faster multi-reference editing. Source: https://docs.bfl.ai/flux_2/flux2_overview

## Notes

Snapshots flux-2-klein-9b (fixed) and flux-2-klein-9b-preview (latest, KV caching). HF also hosts -base, fp8 and nvfp4 variants. Release date = HF repo creation date.

Small, fast FLUX.2 models for real-time/local use; 4B is Apache-2.0.

```bash
curl -X POST https://api.bfl.ai/v1/flux-2-klein-4b -H "x-key: $BFL_API_KEY" -H "Content-Type: application/json" -d '{"prompt":"minimal poster, the word KLEIN in bold red"}'
```
Local: `diffusers` with `black-forest-labs/FLUX.2-klein-4B`.

Sources: https://docs.bfl.ai/flux_2/flux2_overview , https://docs.bfl.ai/quick_start/pricing , https://huggingface.co/black-forest-labs

Model page: https://postcutoff.com/m/flux-2-klein/