Staff AI Runtime Engineer

FlexAI is building a high-performance, cloud-agnostic AI compute platform designed for next-generation training and inference workloads. As a Staff AI Runtime Engineer, you will play a pivotal role in the design, development, and optimization of the core runtime infrastructure that powers distributed training and deployment of large AI models.

Responsibilities:

• Own the core runtime architecture supporting AI training and inference at scale
• Design resilient and elastic runtime features (e.g. dynamic node scaling, job recovery) within our custom PyTorch stack
• Optimize distributed training reliability, orchestration, and job-level fault tolerance
• Profile and enhance low-level system performance across training and inference pipelines
• Improve packaging, deployment, and integration of customer models in production environments
• Ensure consistent throughput, latency, and reliability metrics across multi-node, multi-GPU setups
• Design and maintain libraries and services that support model lifecycle: training, checkpointing, fault recovery, packaging, and deployment
• Implement observability hooks, diagnostics, and resilience mechanisms for deep learning workloads
• Champion best practices in CI/CD, testing, and software quality across the AI Runtime stack
• Work cross-functionally with Research, Infrastructure, and Product teams to align runtime development with customer and platform needs
• Guide technical discussions, mentor junior engineers, and help scale the AI Runtime team’s capabilities