Black Forest Labs

BFL founded 2024 by ex-Stability team. FLUX.1 12B rectified flow. $100M+ seed. Open-weight image SOTA. Model-only release. No consumer product.

Black Forest Labs (BFL) founded in 2024 by ex-Stability Diffusion researchers (Robin Rombach, Andreas Blattmann), raised $100M+ seed, releasing FLUX.1 (12B rectified flow) as open-weight SOTA for image generation, no product — model release only.

Founded: 2024 · HQ: Freiburg im Breisgau, Germany · Team: 108 · CEO: Robin Rombach · Funding: $330M total: ~$30M initial (2024) + $300M Series B (Dec 2025, Salesforce Ventures + AMP + a16z + Northzone + Creandum + Bain Capital Ventures) · Valuation: $3.25B (December 2025)

About Black Forest Labs

Black Forest Labs is a German-American AI research company founded in 2024 by Robin Rombach, Andreas Blattmann, Patrick Esser, and Dominik Lorenz, all core researchers behind the latent diffusion models that powered Stable Diffusion. The founding team left Stability AI in early 2024, citing concerns about the company's ability to fund large-scale research. Black Forest Labs emerged from stealth in August 2024 with the FLUX.1 model family, which rapidly became the most downloaded image generation models on Hugging Face. The company is headquartered in Freiburg im Breisgau, Germany, with additional offices in San Francisco. The flagship product is the FLUX model family, spanning FLUX.1 (August 2024) and FLUX.2 (November 2025). FLUX.2 is a 32-billion-parameter rectified flow transformer that generates images up to 4 megapixels with multi-reference conditioning, sub-10-second generation time, and exact hex color matching. The model family includes five variants: FLUX.2 [max] for cinematic photorealism, FLUX.2 [pro] for production API use at $0.03 per image, FLUX.2 [flex] for developer-tunable inference, FLUX.2 [dev] as a 32B open-weight model for non-commercial research, and FLUX.2 [klein] in 4B and 9B sizes for sub-second consumer-GPU generation. Black Forest Labs' models power image generation and editing for major platforms including Meta, Canva, Adobe, and Microsoft. The FLUX models are among the most popular image generation checkpoints on Hugging Face, with tens of millions of downloads across the FLUX.1 and FLUX.2 families. FLUX.2 Dev and FLUX.2 Klein weights are publicly available under BFL's non-commercial open weights license, while the commercial API tiers serve teams needing managed infrastructure at scale. Funding reflects strong investor conviction in the team's background and technical edge. Black Forest Labs raised approximately $30 million in an initial round in 2024, followed by a $300 million Series B in December 2025 co-led by Salesforce Ventures and AMP at a $3.25 billion valuation. Existing investors including Andreessen Horowitz, Northzone, Creandum, and Bain Capital Ventures also participated. Total funding stands at approximately $330 million as of December 2025. Proceeds are directed at expanding research, increasing compute capacity, and scaling teams across Freiburg, San Francisco, and London. CEO Robin Rombach received his PhD from LMU Munich and previously served as Research Director at Stability AI, where he led the team that built Stable Diffusion 2 and 3. Co-founder Andreas Blattmann authored Align Your Latents, the foundational video diffusion paper. Patrick Esser contributed to high-resolution image synthesis research underpinning latent diffusion. The company employs approximately 108 people as of mid-2026. The technical philosophy centers on rectified flow transformers, which produce cleaner geometry and faster convergence with fewer denoising steps compared to traditional DDPM diffusion. FLUX.2 couples a Mistral-3 24B vision-language model with the flow transformer to improve text understanding and prompt adherence. A redesigned VAE addresses geometry and texture degradation seen in FLUX.1 at high resolutions, enabling reliable 4MP generation. The licensing strategy balances open community access with commercial revenue. FLUX.2 Dev (32B) is freely downloadable on Hugging Face under a non-commercial license. Commercial SaaS products using the open weights must negotiate a license with Black Forest Labs above 100,000 images per month. Klein variants (4B and 9B) support commercial self-hosting, running on consumer hardware with as little as 13GB VRAM.

Mission

To build the next generation of visual intelligence models that understand creative intent and transform imagination into reality.

Products

• FLUX.2 API
• FLUX.2 [dev] Open Weights
• FLUX.2 [klein]
• BFL Playground

Links

Website · GitHub · Twitter · LinkedIn · Blog · Docs