FullStack Engineer, AI Observability & Evals Platform (LangSmith)

About this role

LangChain seeks a Fullstack Engineer to build features for LangSmith, an AI observability and evaluation platform used by Fortune 500 companies. You'll work across Go, Python, and TypeScript stacks, collaborating with product teams and enterprise customers to ship high-impact features at scale.

What you'll do

• Develop product features across Go/Python backend and React/TypeScript frontend
• Collaborate with product and design teams to iterate on features and roadmap
• Design and scale APIs for high-performance, data-intensive applications
• Write clean, maintainable, well-tested code while meeting aggressive timelines
• Engage directly with enterprise customers to understand needs and drive feedback
• Own projects end-to-end with a focus on shipping and iterating quickly

What they're looking for

• Go or Python backend development
• React and TypeScript frontend development
• PostgreSQL and Redis database systems
• API design and scaling
• Full-stack platform product development
• Strong communication and cross-functional collaboration
• AI/LLM applications (bonus)
• Observability or developer tools experience (bonus)

Benefits

• Medical, dental, and vision coverage
• Flexible vacation
• 401(k) plan
• Meals provided on in-office days (US)
• Meaningful equity
• Locally competitive benefits for EU, UK, and APAC regions