FLUX (Black Forest Labs)

FLUX is the model family that took the open-weight photorealism crown. Black Forest Labs — founded by researchers who worked on the original Stable Diffusion — ships FLUX.2 across five tiers, from an Apache 2.0 distilled model you can run anywhere to a frontier API model. FLUX is now the default comparison point for anyone evaluating open image models.

What is FLUX?

FLUX is Black Forest Labs' frontier image generation and editing family. FLUX 2 launched on 25 November 2025 and ships in four base tiers: Pro for production API use, Flex for developers who want parameter-level control, Dev as a 32B open-weight release on Hugging Face, and Klein, an Apache 2.0 distilled variant small enough to run widely. Above them sits FLUX.2 [max], the top-tier model, which pushes image quality, prompt understanding and editing consistency to the highest level in the family. The tiering is unusually thoughtful: you can prototype on Klein, self-host Dev, and move to Pro or Max in production without changing prompt style.

Key Features

• FLUX.2 [max]: The quality ceiling of the family, for work where photorealism and prompt fidelity matter most.
• Open weights on Dev and Klein: FLUX.2 [dev] is a 32B open-weight release; Klein ships under Apache 2.0, one of the most permissive licences in the category.
• Editing as a first-class capability: Consistent image-to-image editing rather than generation only.
• Megapixel pricing: Cost scales with resolution, so small iterations are cheap and only finals cost real money.
• Wide availability: Native API on bfl.ai plus distribution through OpenRouter, fal and other inference hosts.

Who Should Use FLUX?

FLUX suits product teams generating photorealistic marketing and e-commerce imagery, developers who need an image API with clear per-megapixel economics, and anyone who wants open weights without settling for older Stable Diffusion quality. Klein under Apache 2.0 is particularly attractive for commercial products that need permissive licensing. If your priority is stylistic artistry rather than realism, Midjourney is still stronger; if you need the largest tooling ecosystem, Stable Diffusion still wins on ControlNets and LoRAs.

Pricing

Black Forest Labs prices its API in credits, where 1 credit equals $0.01. As checked on 31 July 2026, FLUX.2 text-to-image starts at $0.014 for Klein 4B, $0.015 for Klein 9B, $0.03 for Pro, $0.05 for Flex and $0.07 for Max. Billing is megapixel-based, so cost scales with output resolution — Pro works out to roughly $0.03 per megapixel of combined input and output, meaning a 1024×1024 generation with no input image lands at about $0.03. FLUX.2 [dev] weights are free to download from Hugging Face, and Klein is released under Apache 2.0.

Pros and Cons

Bottom Line

FLUX.2 is the open-weight family to beat in 2026. Klein gives you an Apache 2.0 model for commercial products, Dev gives you self-hostable frontier quality, and Pro and Max cover production API work with transparent pricing. For photorealistic and editing-heavy workloads it is the strongest recommendation in this category; pair it with Midjourney when the brief calls for artistry rather than realism.