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Member of Technical Staff, Research Engineer

Crosby· Engineering
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New York City$200k - $300kFull-timePosted 11mo ago

About the role

Research Engineer role bridging research and production, focusing on building scalable AI features, RL fine-tuning infrastructure, and deploying production-grade AI systems for contract review and legal workflows at Crosby.

Responsibilities

  • Build core AI Systems: Design, build, and scale our primary AI features, including complex Retrieval Augmented Generation (RAG) pipelines and agentic workflows that improve contract review, playbook retrieval and docx editing.
  • Build RL fine-tuning infrastructure: Stand up and harden RL training infrastructure (PPO, GRPO, and related methods) for scalable training.
  • Enable RL in a non-verifiable domain: Build reward pipelines, generators, and formal verification harnesses for scalable RL in contract review.
  • Customize Models for Impact: Fine tune and adapt language models for highly specific legal tasks.
  • Ensure Production Quality: Develop evaluation and monitoring systems to catch regressions and reward hacking before users.
  • Apply AI Pragmatically: Identify effective techniques and tools to solve immediate product challenges.
  • Collaborate to Ship: Work with product, backend, and in-house legal experts to deliver end-to-end solutions.

Qualifications

  • 3+ years of professional software engineering experience building and shipping AI/ML-powered products, with deep proficiency in Python and production-grade systems.
  • Familiarity with post-training techniques such as SFT and GRPO, and experience with distributed model training, VERL, and vLLM.
  • Hands-on experience with LLM APIs (e.g., OpenAI, Anthropic), RAG, agentic workflows, and full ML project lifecycle.
  • Data-driven problem solving with strong intuition for building infrastructure vs. simple solutions.
  • Product-focused with ability to ship value quickly; ownership of features from concept to deployment.

Skills

Required:PythonRetrieval Augmented Generation (RAG)RL fine-tuning (PPO, GRPO)Post-training techniques (SFT, GRPO)LLM APIs (OpenAI, Anthropic)

Benefits

  • Unlimited PTO
  • Lunch & dinner in the office every day
  • Medical insurance (multiple plan options through Anthem & Cigna)
  • HSA or FSA, depending on plan
  • Dental insurance
  • Vision insurance
  • One Medical membership
  • 401(k) match
  • In-office desk setup stipend
Last updated Aug 12, 2026. Interested? Apply on the company site.

About Crosby

The Agentic Law Firm Built for Execution

Crosby is the Agentic Law Firm Built for Execution. Lawyer-assisted AI reviews MSAs, DPAs and NDAs in under an hour.

AIContractsDPAsLegalMSAsNDAsvertical-agents-and-applicationswing-list-2026
Company profileWebsite

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