Black Forest Labs: FLUX 3 Image API

Black Forest Labs: FLUX 3 Image is part of the FLUX 3 multimodal foundation model family announced on July 23, 2026. It generates images from text prompts and edits images from an image plus a prompt. The model supports multi-reference generation with up to 10 reference images and produces native 4K resolution output. It offers pixel-level precise editing and uses bounding boxes to control element placement and limit edit regions. Rather than short prompts, it accepts full scene captions, and it pairs with a 9B prompt upsampler model that expands requests into detailed scene descriptions via system prompt. The image transformer is provided as a 5.6B-parameter open-weight model, with a model size of 6B parameters in BF16 tensor type. It uses Qwen3-VL-4B-Instruct as the text encoder. An undistilled base version (Klein Base) is available for fine-tuning, LoRA training, and research, while a distilled Klein version is offered for generation, editing, and self-hosting. The checkpoint behind the BFL API is the distilled version. It integrates with the Diffusers library from day one and runs on RTX 4070-class GPUs. FLUX 3 Image is suited to text-to-image generation, single-reference image editing, multi-reference image composition, design and advertising production, and product visualization. According to internal evaluations, FLUX 3 Image Klein placed first in text-to-image, multi-reference generation, and image editing rankings. It improves over FLUX.2 Klein 9B by 91 Elo points in text-to-image and 70 Elo points in image editing, while reducing parameter count by 38%. It outperforms larger open-weight models such as Qwen-Image 2.1 (7B parameters) and Krea 2 (12.9B parameters), and surpasses closed models Ideogram V4.5 and FLUX.2 Pro. Note that the flux-kommunity-license imposes conditions on commercial use.

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It accepts text input and image input, and produces image output. It supports text-to-image generation and image editing from an image plus a prompt, including multi-reference generation with up to 10 reference images.

It generates at native 4K resolution.

It provides pixel-level precise editing and uses bounding boxes to control element placement and limit edit regions.

The undistilled base version (Klein Base) is intended for fine-tuning, LoRA training, and research. The distilled Klein version is offered for generation, editing, and self-hosting. The base version runs at 50 steps with guidance 3.5, while the distilled version runs at 16 steps without guidance.

Yes. It pairs with a 9B prompt upsampler model that expands requests into detailed scene descriptions via system prompt.

The flux-kommunity-license imposes conditions on commercial use. The Qwen3-VL-4B-Instruct text encoder is under the Apache-2.0 license.