Member of Technical Staff - Mid-Training Infra

San Francisco, CA FullTime

Posted 4mo ago

Job Location

San Francisco, CA

Tech Stack

Remote Work Policy

On-site

Employment Type

FullTime

Categories

AI Infrastructure Engineer

About the job

Reflection is a research lab dedicated to making intelligence open and accessible. We build open models that empower individuals to control their intelligence and shape the future of AI. As a Member of Technical Staff focused on Mid-Training Infrastructure, you will be instrumental in designing, building, and operating large-scale GPU infrastructure crucial for high-throughput model inference and mid-training workloads. This role involves developing systems that support synthetic data generation and reinforcement learning pipelines at scale, as well as building high-performance inference platforms capable of serving and evaluating models across thousands of GPUs.

Responsibilities

  • Design, build, and operate large-scale GPU infrastructure for high-throughput model inference and mid-training workloads.
  • Develop systems powering synthetic data generation and reinforcement learning pipelines at scale.
  • Build high-performance inference platforms for serving and evaluating models across thousands of GPUs.
  • Optimize throughput, latency, and GPU utilization for large language model inference and rollout workloads.
  • Build infrastructure supporting reinforcement learning pipelines, including large-scale rollout generation, evaluation, and policy improvement loops.
  • Support research teams with distributed RL workloads and large-scale model evaluation infrastructure.
  • Improve model execution performance through kernel-level optimization, model parallelism, and GPU runtime enhancements.
  • Develop distributed systems for large-scale synthetic data generation and RL-driven training workflows.
  • Diagnose and resolve performance bottlenecks across inference runtimes, GPU kernels, networking, and distributed compute systems.

Requirements

  • Experience deploying and operating large-scale GPU systems for inference or model serving.
  • Several years of hands-on experience building and running production infrastructure.
  • Strong understanding of GPU performance characteristics and optimization techniques.
  • Experience with modern inference frameworks like SGLang, Megatron, or similar high-performance LLM runtimes.
  • Familiarity with distributed reinforcement learning infrastructure or rollout generation systems.
  • Experience optimizing throughput for large-scale model execution workloads.
  • Experience working with GPU kernels or low-level performance optimization.
  • Familiarity with infrastructure for synthetic data pipelines or RL training workflows.
  • Experience debugging performance issues across GPU, networking, and distributed execution layers.

Benefits

  • Top-tier compensation: Salary and equity structured to recognize and retain talent globally.
  • Stock options
  • Comprehensive medical, dental, vision, and life insurance
  • Annual wellness allowance
  • Provided lunch and dinner in the office daily
  • 22 weeks paid parental leave for all new parents
  • Unlimited paid time off in the U.S.
  • 30 days paid time off in the U.K.
  • Sponsorship support for visas and long-term immigration pathways
  • Regular off-sites, happy hours, and team celebrations

About Reflection ai

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