Member of Technical Staff, Research Engineer

The role

You will bridge research and production by turning validated methods and evaluation infrastructure into production-grade features. You will build core AI systems, RL fine-tuning infrastructure, and customize models for legal tasks.

What you will do

• Design, build, and scale primary AI features including RAG pipelines and agentic workflows
• Stand up and harden RL training infrastructure
• Build reward pipelines, generators, and formal verification harnesses
• Selectively fine tune and adapt language models
• Develop evaluation and monitoring systems
• Identify effective AI techniques to solve product challenges
• Work with product, backend, and legal experts to deliver solutions

Required qualifications

• 3+ years of professional software engineering experience building and shipping AI/ML-powered products
• Deep proficiency in Python
• Proven track record of scalable, production-grade systems
• Familiarity with post-training techniques such as SFT and GRPO
• Hands-on experience with distributed model training, VERL, and vLLM
• Hands-on experience with LLM APIs (e.g., OpenAI, Anthropic), RAG, and agentic workflows
• Experience with the full ML project lifecycle

Benefits

• Unlimited PTO
• Lunch & dinner in the office every day
• Medical insurance (multiple plan options through Anthem & Cigna)
• HSA or FSA, depending on your plan choice
• Dental insurance
• Vision insurance
• One Medical membership
• 401(k) match
• In-office desk setup stipend

Before you apply

• Background checks for applicants will be administered in accordance with applicable law

About the company

Crosby is an AI-native law firm that combines human expertise with technology to help companies sign commercial contracts faster. The company builds proprietary tools and human-in-the-loop workflows for corporate legal teams.