Tzafon is a foundation model lab building scalable compute systems and advancing machine intelligence, with offices in San Francisco, Zurich & Tel Aviv. We’ve raised over $12m in funding to advance our mission of expanding the frontiers of machine intelligence.

We're a team of engineers and scientists with deep backgrounds in ML infrastructure & research. Founded by IOI and IMO medalists, PhDs, and alumni from leading tech companies, we train models and build infrastructure for swarms of agents to automate work across real-world environments.

You'll work between our product and post-training teams to ship Large Action Models that actually work. Build evals, benchmarks, and fine-tuning pipelines. Define what good model behavior means and make it happen at scale.

What you'll do

• Build evaluation infrastructure for agent systems

• Create benchmarks that measure real capability

• Design data pipelines for behavioral data collection and analysis

• Implement fine-tuning pipelines (wandb, distributed training infrastructure)

• Work with post-training team on RLHF and behavioral optimization

• Build tools for model introspection and capability mapping

• Ship continuous evaluation systems that catch regressions before users do

We're looking for

• Expert-level at Python and ML frameworks (PyTorch)

• Deep experience with LLM fine-tuning and evaluation infrastructure

• Track record of shipping ML systems to production

• Strong opinions on what makes a good eval

• Experience with wandb, MLflow, or similar experiment tracking

Preferred Experience

• Built eval frameworks at AI labs or LLM companies

• RLHF/Constitutional AI/DPO implementation experience

• Published work on model evaluation or benchmarking

• Contributions to open source ML infrastructure

• Experience with multi-agent systems or tool-use models

Life at Tzafon

• Full medical, dental, and vision coverage, plus 401(k) in the US

• Office in SF, Zurich and Tel Aviv

• Early-stage equity in a future-defining company

Visa sponsorship: We do sponsor visas! However, we aren't able to successfully sponsor visas for every role and every candidate. But if we make you an offer, we will make every reasonable effort to get you a visa, and we retain an immigration lawyer to help with this.

Compensation starts at $150k-$400k + equity package, depending on experience & location.

We also offer a referral bonus of $5k for referral of successful hires (send to [email protected]).