Black Forest Labs launches open source Flux.2 [klein] to generate AI images in less than a second

The German AI startup Black Forest Labs (BFL), founded by former Stability AI engineers, is continuing to build out its suite of open source AI image generators with the release of FLUX.2 [klein], a new pair of small models — one open and one non-commercial — that emphasizes speed and lower compute requirements, with the models generating images in less than a second on a Nvidia GB200.

The [klein] series, released yesterday, includes two primary parameter counts: 4 billion (4B) and 9 billion (9B).

The model weights are available on Hugging Face and code on Github.

While the larger models in the FLUX.2 family ([max] and [pro]), released in November of 2025, chase the limits of photorealism and "grounding search" capabilities, [klein] is designed specifically for consumer hardware and latency-critical workflows.

In great news for enterprises, the 4B version is available under an Apache 2.0 license, meaning they — or ...