The posting
ABOUT BLACK FOREST LABS
We’re the team building the foundational layer for visual intelligence: multimodal models trained jointly on images, video, audio, and action to see, generate, and understand the world.
Our founding team pioneered latent diffusion and Stable Diffusion, the breakthroughs that made generative AI accessible to millions. With FLUX, we're pushing into generative media at scale, machines that act in the physical world, and emerging applications in computer use.
Our FLUX models top public benchmarks and run in production in some of the world's biggest platforms. We're a small, fast growing research lab competing with the largest companies in the world. From our labs in Freiburg to San Francisco, we're building what comes next.
WHY THIS ROLE
You'll train large-scale diffusion models for image and video generation, exploring new approaches while maintaining the rigor that helps us distinguish meaningful progress from incremental tweaks. This isn't about following established recipes—it's about running the experiments that clarify which architectural choices matter and which are less impactful.
WHAT YOU’LL WORK ON
- Trains large-scale diffusion transformer models for image and video data, working at the scale where intuitions break and empirical evidence matters
- Rigorously ablates design choices—running experiments that isolate variables, control for confounds, and produce insights you can actually trust—then communicating those results to shape our research direction
- Reasons about the speed-quality tradeoffs of neural network architectures in production settings where both constraints matter simultaneously
- Fine-tunes diffusion models for specialized applications like image and video upscalers, inpainting/outpainting models, and other tasks where general-purpose models aren't enough
WHAT WE’RE LOOKING FOR
You've trained large-scale diffusion models and developed strong intuitions about what matters. You know that at research scale, every design choice has tradeoffs, and the only way to know which ones are worth making is through careful ablation. You're comfortable debugging distributed training issues and presenting research findings to the team.
You likely have:
- Hands-on experience training large-scale diffusion models for image and video data, with practical knowledge of common failure modes and what matters most in training
- Experience fine-tuning diffusion models for specialized applications—upscalers, inpainting, outpainting, or other tasks where understanding the domain matters as much as understanding the architecture
- Deep understanding of how to effectively evaluate image and video generative models—knowing which metrics correlate with quality and which are just convenient proxies
- Strong proficiency in PyTorch, transformer architectures, and the full ecosystem of modern deep learning
- Solid understanding of distributed training techniques—FSDP, low precision training, model parallelism—because our models don't fit on one GPU and training decisions impact research outcomes
We'd be especially excited if you:
- Have experience writing forward and backward Triton kernels and ensuring their correctness while considering floating point errors
- Bring proficiency with profiling, debugging, and optimizing single and multi-GPU operations using tools like Nsight or stack trace viewers
- Know the performance characteristics of different architectural choices at scale
- Have published research that contributed to how people think about generative models
HOW WE WORK TOGETHER
We’re a distributed team with real offices that people actually use. This role is based in Freiburg, and you’ll join us in the office at least 2 days a week, or one full week every other week.
EVERYTHING WE DO IS GROUNDED IN FOUR VALUES:
- Obsessed. We are a frontier research lab. The science has to be right, the understanding deep, the product beautiful.
- Low Ego. The work speaks. The best idea wins, no matter who said it. Credit is shared. Nobody is above any task.
- Bold. We take the ambitious bet. We ship, we do not wait for conditions to be perfect.
- Kind. People over politics. We treat each other with genuine warmth. Agency without empathy creates chaos.
If this sounds like work you’d enjoy, we’d love to hear from you.
Base Annual Salary:
EU €130,000-€340,000 + Equity
Note: We may use AI-assisted tools to help organize applications. All hiring decisions are always made by our team.
