Senior / Staff Machine Learning Engineer, Applied AI

Location: Cambridge, MA, USA or San Francisco, CA, USA

Salary: $180,000–$298,000 USD base salary per year, with bonus potential and early-stage equity.

Company

hirify.global is building AI systems and proprietary instruments to automate the scientific method and accelerate discovery across medicine, materials, and energy.

What you will do

• Adapt AI models to customer-specific scientific workflows and close the gap between model capabilities and real-world use.
• Run post-training using SFT and reinforcement learning methods such as DPO, PPO, and GRPO.
• Design and operate evaluation loops measuring model quality, reliability, and customer fit.
• Convert customer feedback, data signals, and evaluation results into model improvement cycles.
• Partner with AI Researchers and Software teams to integrate model behavior into end-to-end product workflows.
• Debug complex model failures using traces, evaluations, logs, customer context, and scientific feedback.

Requirements

• At least 1–2 years of hands-on experience with model post-training and evaluation system design.
• Strong software engineering skills in Python and modern machine learning frameworks such as PyTorch.
• Experience debugging ambiguous, high-stakes model behavior using data, traces, logs, and qualitative feedback.
• Deep familiarity with large language models, multimodal models, or agentic AI systems.
• Clear communication skills for translating customer needs into technical approaches and explaining complex model behavior to technical and non-technical audiences.
• Ability to work in the United States at the Cambridge or San Francisco location.

Nice to have

• Experience adapting models for customer-facing or production workflows, especially in scientific, technical, or data-intensive domains.
• Experience with RLHF, GRPO, tool-augmented reinforcement learning, evaluation harnesses, model monitoring, or quality dashboards.
• Experience training mixture-of-experts architectures.
• Experience mentoring engineers and serving as a technical expert.

Culture & Benefits

• Startup-speed environment focused on scientific AI and technically challenging problems.
• Full-time U.S. employees receive medical, dental, and vision coverage.
• Benefits include employer-paid life and disability insurance, flexible time off, company holidays, and paid parental leave.
• Educational assistance, commuter benefits, and subsidized lunch are available; commuter benefits include bike-share memberships for office-based employees.
• Full-time employees outside the U.S. receive benefits tailored to their region, with local-market salary structures.