Senior AI Engineer

About the role

Poseidon is building the data infrastructure the next generation of AI will depend on. Foundation models are not limited by compute. They are bottlenecked by rare, high-quality, IP-safe data that actually improves performance: the long-tail, edge-case, multi-modal datasets that cannot be scraped or synthetically generated. We are creating a decentralized data layer connecting AI companies with the datasets they need. Poseidon is the infrastructure that makes scalable, compliant, demand-driven data sourcing possible. Backed by a16z, we are early, moving fast, and looking for mission-driven teammates to shape this category.

Responsibilities

• Build scalable pipelines for multimodal data processing and model training
• Productionize research workflows so models and training processes can run reliably in production
• Design infrastructure that supports data ingestion, annotation, labelling, dataset generation, and model fine-tuning
• Build internal services and tooling used by researchers to run training and evaluation workflows
• Optimize GPU and compute utilization across training pipelines
• Implement monitoring, logging, and observability across ML systems
• Ensure pipelines are reproducible, performant, and production ready

Requirements

• ~3-5+ years building production machine learning systems
• Bachelor or Master (preferred) in Computer Science, Engineering, Math, or related area
• Strong Python engineering experience
• Experience building scalable data pipelines or ML infrastructure
• Experience working with modern ML frameworks such as PyTorch, Ray, NeMo
• Familiarity with GPU compute and CUDA concepts
• Experience deploying ML systems in production environments
• Experience working with cloud infrastructure (AWS preferred) and infrastructure platforms such as Prime
• Familiarity with containerization and deployment patterns (Docker or similar)