Principal Machine Learning Engineer, Applied AI

MailerMen is seeking a Principal Machine Learning Engineer for its Applied AI organization. The role adapts AI models to customer-specific scientific workflows through post-training, evaluation, and production ML systems, working with research and software teams to deliver reliable product capabilities.

Responsibilities:

• Apply deep, hands-on expertise to close the last-mile gap between Lila's model capabilities and customer-specific scientific workflows
• Lead post-training efforts using approaches such as SFT and RL (DPO, PPO/GRPO) to align model behavior with customer-specific requirements and feedback
• Build and run evaluation loops that measure model quality, reliability, and customer fit, using patterns you've refined across many prior projects
• Turn customer learnings, data signals, and evaluation results into concrete model improvement cycles
• Partner with AI researchers to translate model advances into reliable, usable capabilities
• Work with Software to integrate model behavior into end-to-end product workflows
• Debug complex model failures using traces, evaluations, customer context, and scientific feedback
• Mentor engineers and share reusable patterns for model adaptation, evaluation, and deployment, drawing on lessons learned across a long track record of shipping ML systems