FullStack Engineer, Observability & Evals Platform; LangSmith

Full Stack Engineer, Observability & Evals Platform (Lang Smith)

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At Lang Chain, our mission is to make intelligent agents ubiquitous. We provide the agent engineering platform and open source frameworks developers need to ship reliable agents fast.

Our open source frameworks, Lang Chain and Lang Graph, see over 90+ million downloads per month and help developers build agents with speed and granular control. Lang Smith offers observability, evaluation, and deployment for rapid iteration, enabling teams to transform LLM systems into dependable production experiences.

Lang Chain is trusted by millions of developers worldwide and powers AI teams at companies like Replit, Clay, Cloudflare, Harvey, Rippling, Vanta, Workday, and more.

In person 5 days/week in San Francisco

We're looking for a Fullstack Engineer to work on Lang Smith, our commercial AI observability and evals platform product. In this role, you'll have the opportunity to build new features and functionality for the platform while working close enterprise customers, developer end-users and internal stakeholders.

• Develop and implement key product features working across our entire Go, Python, and Typescript stack
• Collaborate closely with product and design teams to iterate on new features and enhance the product roadmap
• Drive aggressive project timelines while ensuring high engineering standards are being met by writing clean, maintainable, and well-tested code

• 2+ 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
• Solid understanding of database systems, particularly Postgres and Redis
• Experience designing and scaling APIs, preferably in high-performance, data-intensive applications
• Strong ownership and a “get stuff done” mindset - comfortable shipping fast and iterating based on user feedback
• Strong communicator with the ability to collaborate closely with various internal stakeholders and engage directly with our top-tier customers
• Bonus:
  Experience with AI/LLM-powered applications, developer tools, or observability platforms

• We offer competitive compensation that includes base salary, meaningful equity, and benefits such as health and dental coverage, flexible vacation, a 401(k) plan, and life insurance. Actual compensation will vary based on role, level, and location. For team members in the EU and UK, we provide locally competitive benefits aligned with regional norms and regulations.
• Annual salary range: $,000 USD

Entry level

Full-time

Engineering and Information Technology

Technology, Information and Internet