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Research Engineer, LangSmith Engine

LangChain· Engineering
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New York, NY, San Francisco, CA$240k - $280kFull-timePosted 2mo ago

About the role

Research engineer role focused on making the LangSmith Engine more capable and efficient by studying real agent failures, building benchmarks, running experiments, and turning successful ideas into production improvements. Requires production engineering understanding and a focus on cost, latency, reliability, and scalability.

Responsibilities

  • Build and maintain benchmarks and evaluations that measure the quality and efficiency of Engine agents on real-world tasks.
  • Design and run experiments to improve agent performance across models, prompting, context, tools, orchestration, and agent strategies.
  • Explore and implement post-training and fine-tuning techniques when they meaningfully improve agent capabilities, quality, or cost.
  • Turn successful experiments into production improvements, working closely with engineers and researchers to measure impact and prevent regressions.
  • Help define the ML roadmap and technical direction for improving Engine agents, and mentor other engineers through strong technical leadership.

Qualifications

  • 4+ years of experience in ML/AI research, or a closely related field.
  • Master’s or Ph.D. in a relevant scientific field.
  • Hands-on experience working with LLMs and AI agents, including analyzing model behavior and improving real-world performance.
  • Strong experience designing benchmarks, evaluations, and experiments for AI/ML systems; ability to assess whether changes improve an agent.
  • Strong software engineering skills with a track record of moving ideas from research prototype to measurable production impact.
  • Maximal agency and strong research judgment: ability to identify high-impact problems, work through ambiguity, move quickly, and communicate findings clearly.

Skills

Required:Benchmarks and evaluationsExperiment design and analysisProduction engineering collaboration
Nice to have:Post-training and fine-tuning techniques

Benefits

  • medical, dental, and vision coverage, flexible vacation, a 401(k) plan, meals on in-office days in the US and more.
Last updated Oct 14, 2026. Interested? Apply on the company site.

About LangChain

Engineer reliable agents

LangChain provides the engineering platform and open source frameworks developers use to build, test, and deploy reliable AI agents.

AI agentsagent engineeringbrex-fastest-growing-2025liquid-ai-recruiting-targetopen source frameworksplatform
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