Senior Research Engineer, Model Training / Pretraining

Senior Research Engineer

Seattle, Washington | Hybrid

The position is a Senior Research Engineer on the model scaling team, reporting to a Director of AI Research. The work covers model training and the supporting infrastructure. Training runs use approximately 600 B300 and 1,000 H100 GPUs.

Responsibilities

• Build and maintain the training stack for distributed model training across GPU clusters.
• Run scaling experiments covering model architecture, data, and optimisation.
• Work in one specialist area: GPU kernel development (CUDA), Mixture-of-Experts architectures, or reinforcement-learning post-training (GRPO, PPO, RLVR).
• Release models, code, and associated research publicly.

Requirements

• 6+ years of software engineering experience.
• 4+ years of machine-learning infrastructure experience.
• Python and PyTorch.
• Experience training models from scratch (pretraining). Experience limited to retrieval-augmented generation or application-level fine-tuning does not meet this requirement.
• Depth in at least one of: CUDA kernels, Mixture-of-Experts, or reinforcement learning (GRPO, PPO, RLVR).

Also considered

• JAX.
• Open-source contributions.
• Published research.
• Experience with GPU clusters at the scale described above.

Interview process

1. Hiring-manager screen — 25 minutes.
2. Recruiter screen — 15 minutes.
3. Machine-learning coding interviews — two sessions, 45 minutes each.
4. Machine-learning system-design interview — 45 minutes.
5. Technical deep-dive with the Director of AI Research — 60 minutes.
6. Final interview — 30 minutes.
7. Offer.

• Base salary: $147,000–$220,000 + strong bonus programmes in addition to base salary.
• Hybrid in Seattle, Washington. On-site presence is required. Fully remote is not available.
• Visa sponsorship is available.

Application

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