Black Forest Labs: FLUX.2 [klein] 4B

black-forest-labs/flux-2-klein-4b

Access FLUX.2 [klein] 4B AI image generation using Puter.js API.

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Model Card

FLUX.2 Klein 4B is a compact, Apache 2.0 licensed model distilled from the full FLUX.2 architecture, capable of sub-second image generation on consumer GPUs with ~13GB VRAM. It supports text-to-image, image editing, and multi-reference generation in a unified model.

Cost Per Image N/A

per generation

Configuration N/A

resolution

Release Date Jan 15, 2026

 

Code Example

Use FLUX.2 [klein] 4B in your app with the Puter.js AI API — no API keys or setup required.

// npm install @heyputer/puter.js
import { puter } from '@heyputer/puter.js';

puter.ai.txt2img("A serene mountain landscape at sunset", {
    model: "black-forest-labs/flux-2-klein-4b"
}).then(image => {
    document.body.appendChild(image);
});

<html>
<body>
    <script src="https://js.puter.com/v2/"></script>
    <script>
        puter.ai.txt2img("A serene mountain landscape at sunset", {
            model: "black-forest-labs/flux-2-klein-4b"
        }).then(image => {
            document.body.appendChild(image);
        });
    </script>
</body>
</html>

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FLUX.2 [klein] 9B

FLUX.2 Klein 9B is a larger variant of the Klein family built on a 9B flow model with an 8B Qwen3 text embedder, matching or exceeding models 5x its size in quality. It offers higher output diversity than the 4B distilled variant and is ideal for fine-tuning and research.

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FLUX.1 Kontext [max]

FLUX.1 Kontext Max is the highest-quality model in the Kontext series, optimized for iteratively modifying existing images via text prompts with maximum fidelity. It offers the best editing consistency and prompt following among Kontext variants.

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FLUX.1 Kontext [pro]

FLUX.1 Kontext Pro is a production-grade in-context image generation and editing model that balances quality and speed. It powers integrations in Adobe Photoshop's Generative Fill and Meta's platforms.

Frequently Asked Questions

How do I use FLUX.2 [klein] 4B?

You can access FLUX.2 [klein] 4B by Black Forest Labs through Puter.js AI API. Include the library in your web app or Node.js project and start making calls with just a few lines of JavaScript — no backend and no configuration required.

Is FLUX.2 [klein] 4B free?

Yes, it is free if you're using it through Puter.js. With the User-Pays Model, you can add FLUX.2 [klein] 4B to your app at no cost — your users pay for their own AI usage directly, making it completely free for you as a developer.

Who created FLUX.2 [klein] 4B?

FLUX.2 [klein] 4B was created by Black Forest Labs and released on Jan 15, 2026.

Does it work with React / Vue / Vanilla JS / Node / etc.?

Yes — the FLUX.2 [klein] 4B API works with any JavaScript framework, Node.js, or plain HTML through Puter.js. Just include the library and start building. See the documentation for more details.

Get started with Puter.js

Add FLUX.2 [klein] 4B image generation to your app without worrying about API keys or setup.

Read the Docs View Tutorials