# FLUX.2 Klein 4B

> FLUX.2 Klein 4B is an open-weight image generation model from Black Forest Labs, released on 14 Jan 2026. It accepts images and text and generates images, with a 41K-token context window and up to 41K output tokens per response.

Source page: https://www.aimodel.directory/models/flux-2-klein-4b
Last verified: 21 Oct 2026

## Specifications

- **Developer:** Black Forest Labs
- **Release date:** 14 Jan 2026 (source: models.dev, https://github.com/sst/models.dev/blob/dev/providers/nvidia/models/black-forest-labs/flux_2-klein-4b.toml)
- **Status:** Generally available (source: models.dev, https://github.com/sst/models.dev/blob/dev/providers/nvidia/models/black-forest-labs/flux_2-klein-4b.toml)
- **Weights:** Open weights (source: models.dev, https://github.com/sst/models.dev/blob/dev/providers/nvidia/models/black-forest-labs/flux_2-klein-4b.toml)
- **Context window:** 41K (40,960 tokens) (source: models.dev, https://github.com/sst/models.dev/blob/dev/providers/nvidia/models/black-forest-labs/flux_2-klein-4b.toml)
- **Max output:** 41K tokens (source: models.dev, https://github.com/sst/models.dev/blob/dev/providers/nvidia/models/black-forest-labs/flux_2-klein-4b.toml)
- **Knowledge cutoff:** Jun 2025 (source: models.dev, https://github.com/sst/models.dev/blob/dev/providers/nvidia/models/black-forest-labs/flux_2-klein-4b.toml)
- **Input:** Images and text (source: models.dev, https://github.com/sst/models.dev/blob/dev/providers/nvidia/models/black-forest-labs/flux_2-klein-4b.toml)
- **Output:** Images (source: models.dev, https://github.com/sst/models.dev/blob/dev/providers/nvidia/models/black-forest-labs/flux_2-klein-4b.toml)
- **Reasoning mode:** No (source: models.dev, https://github.com/sst/models.dev/blob/dev/providers/nvidia/models/black-forest-labs/flux_2-klein-4b.toml)
- **Tool calling:** No (source: models.dev, https://github.com/sst/models.dev/blob/dev/providers/nvidia/models/black-forest-labs/flux_2-klein-4b.toml)

## API pricing (USD per 1M tokens)

| Provider | Input | Output | Cached input | Context |
|---|---|---|---|---|
| NVIDIA NIM | Free | Free | – | 41K |
| Vercel AI Gateway | – | – | – | – |

## FAQ

### What is the context window of FLUX.2 Klein 4B?

FLUX.2 Klein 4B has a context window of 40,960 tokens (41K) and can generate up to 40,960 tokens in a single response, according to models.dev.

### Is FLUX.2 Klein 4B open source?

FLUX.2 Klein 4B is an open-weight model. Check the license terms before commercial use.

### When was FLUX.2 Klein 4B released?

Black Forest Labs released FLUX.2 Klein 4B on 14 Jan 2026, according to models.dev.

### Which providers offer FLUX.2 Klein 4B?

We track FLUX.2 Klein 4B on 2 providers: NVIDIA NIM, Vercel AI Gateway.

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Data licensed CC BY 4.0. Cite as: AI Model Directory, "FLUX.2 Klein 4B", https://www.aimodel.directory/models/flux-2-klein-4b