Founding RL Engineer — Build Ground-Up AI Systems

Wwshemi; San Francisco (CA); On-site; USD 125,000 - 200,000; Full time

Job summary

Wwshemi in San Francisco, CA seeks a founding engineer to build core reinforcement learning systems from the ground up. You will own environment design, model training, evaluation, and help shape the company's technical direction.

You will work directly with the founders, turning research ideas into production, and scaling training on GPU clusters while refining evaluation frameworks and contributing to engineering culture as the team grows.

Qualifications

• Hands-on RL/ML engineering experience (2+ years).
• Experience with policy gradient methods and RLHF is a plus.
• Strong Python and ML framework skills expected.
• Familiarity with distributed training and GPU infra.

Responsibilities

• Design and build RL environments, reward functions, and training pipelines.
• Train and fine-tune models using PPO, GRPO, DPO, RLHF, and RLAIF.
• Develop evaluation frameworks to measure agent performance.
• Scale training on GPU clusters and maintain pipelines.
• Turn research ideas into production systems.

Skills

Python

PyTorch

JAX

Reinforcement learning

RLHF

Ray

CUDA

Kubernetes

Gymnasium

RLlib

MuJoCo

OpenRLHF

Distributed training

Education

CS/Math/Physics degree

Master/PhD preferred

Tools

Ray

CUDA

Kubernetes

Job description

Wwshemi in San Francisco, CA seeks a founding engineer to build core reinforcement learning systems from the ground up. You will own environment design, model training, evaluation, and help shape the company's technical direction.

You will work directly with the founders, turning research ideas into production, and scaling training on GPU clusters while refining evaluation frameworks and contributing to engineering culture as the team grows.