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Pre-training Research Engineer

San Francisco, CA💼 Full-time🗓 2026-08-31 → 2026-09-26

Core

Implement, scale, and improve byte-native and multimodal foundation models through pre-training and architecture research.

Role type

Senior IC pre-training research engineer

Builds

High-quality base models for real-world use cases at scale

Domain

AI infrastructure, multimodal AI, large language models

Deliverable

production ML models

Required skills

large-scale pre-training, model architecture design, distributed training, deep learning fundamentals, research experimentation, robust software engineering, GPU training

Preferred skills

JAX ecosystem, multi-node pre-training systems (FSDP, ZeRO, Megatron), end-to-end training pipeline ownership

Technologies

JAX, Flax, XLA, FSDP, ZeRO, Megatron

Responsibilities

Train large byte-native and multimodal foundation models across massive, heterogeneous corpora; Implement and evaluate new model architectures, training objectives, and optimization methods; Develop stable pre-training recipes and run scaling experiments for novel architectures; Conduct ablations and analyze training dynamics, model behavior, and base-model quality; Work with data and distributed training engineers to improve training efficiency, reliability, and scalability

Seniority

Senior, hands-on IC

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