Senior Fullstack Engineer, AI Observability & Evals Platform

LangChain LangChain · Data AI · San Francisco, CA · Engineering

Senior Fullstack Engineer for LangSmith, an observability and evals platform for AI agents. The role involves leading technical architecture, implementing features across Go, Python, and Typescript, collaborating with product/design, mentoring junior engineers, and ensuring high engineering standards. Requires 5+ years of fullstack experience with Go/Python and React/Typescript, strong database knowledge (Postgres, Redis), and API design/scaling experience. Experience with AI/LLM applications, developer tools, or observability platforms is a bonus. The role is in-person 5 days/week in San Francisco.

What you'd actually do

  1. Lead the technical architecture and implementation of key product features for LangSmith, working across our entire Go, Python, and Typescript stack.
  2. Collaborate closely with product and design teams to iterate on new features.
  3. Mentor and guide more junior members of the team. Drive aggressive project timelines while ensuring high engineering standards are being met.
  4. Lead by example in writing clean, maintainable, and well-tested code

Skills

Required

  • 5+ years of experience in software engineering working on complex platform products
  • Fullstack engineering experience with Go or Python on the backend and React + Typescript on the frontend.
  • Strong understanding of database systems, particularly Postgres and Redis
  • Experience designing and scaling APIs, preferably in a high-performance, data-intensive application
  • Strong communicator with the ability to collaborate closely with various internal stakeholders and engage directly with our top-tier customers
  • Strong ownership mindset

Nice to have

  • Experience with AI/LLM-powered applications, developer tools, or observability platforms

What the JD emphasized

  • observability and evals platform
  • observability and evals platform
  • shipping real AI products
  • complex platform products
  • high-performance, data-intensive application
  • shipping fast and iterating based on user feedback
  • engage directly with our top-tier customers

Other signals

  • LangSmith is an observability and evals platform
  • building, evaluating, deploying, and operating agents at scale
  • shipping real AI products
  • Senior Fullstack Engineer for our commercial product LangSmith, an observability and evals platform