Machine Learning Engineer, RL Environments - New Graduates

Preference Model

Preference Model

Software Engineering, Data Science

San Francisco, CA, USA

Posted on Apr 27, 2026

Location

San Francisco

Employment Type

Full time

Location Type

On-site

Department

Engineering

About Us

Preference Model is building automated ML research engineering.

Existing frontier models are brittle when applied to real-world ML tasks. The present bottleneck is the lack of high-quality RL training environments. Our first step is to build RL environments that reflect real-world complexity, with diverse tasks and robust reward functions.

Our founding team has previous experience on Anthropic’s data team building data infrastructure, and datasets behind Claude. We are partnering with leading AI labs to push AI closer to achieving its transformative potential.

About the Role

This is an entry-level engineering role built for new or recent graduates who are eager to work on one of the most technically exciting problems in AI: building the RL environments that teach frontier models how to think and reason.

You'll join a small, high-ownership team and contribute directly to the data layer that powers frontier LLM capability.

What You Will Do:

  • Design and build RL environments and reward schemes that produce clean, learnable signals for frontier models on ML research and engineering tasks.

  • Build deep expertise across the frontier of ML research, training, and inference infrastructure.

  • Collaborate with others to brainstorm and create new ideas and tools to improve the environment building process.

What We are Looking For (Qualifications):

  • You have strong ML fundamentals and broad research interests. You read many papers or tutorials, understand topics deeply and have the creativity to translate them into RLVR problems.

  • Proficiency in Python and systems programming; ideally PyTorch or JAX

  • Smart problem solvers who take ownership and drives solutions end-to-end

  • Passion for staying current with the rapidly evolving ML infrastructure landscape

  • Ability to meet throughput expectations and respond quickly to feedback

Nice to have:

  • Expert knowledge in an active DL/ML research area, with publications or public code to show for it. Research experience (PhD, MS) is a big plus.

  • Deep understanding of transformer internals

  • Strong expertise in kernel development (CUDA, Triton, Pallas), optimizing non-trivial neural modules to specific hardware

  • Research projects, coursework, or personal work involving RL environments (any framework, any scale)

  • Open-source contributions to ML infrastructure or RL tooling

  • Experience with any cloud platform (AWS, GCP, Azure) or infrastructure-as-code tools

What We Offer:

  • Competitive cash and equity compensation (>90th percentile)

  • Ownership and autonomy in a fast moving startup environment

  • Opportunity to work with top machine learning engineers

  • Health, vision, dental, benefits

  • 401K match

  • Visa sponsorship & relocation support available

We value diverse perspectives and experiences. If you're excited about this role but don't check every box, we still encourage you to apply.