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Salary: USD 175,000 - 240,000 / annual
LangChain is building the foundation for agent engineering, helping developers move from prototypes to production-ready AI agents. The company has raised $125M at Series B and operates a platform including LangSmith (observability, evaluation, deployment, fleet, and sandboxes), open-source frameworks (LangChain, LangGraph, Deep Agents), and LangSmith Engine for autonomous agent improvement. The platform serves 6,000+ active customers and is used by 5 of the Fortune 10 and 35% of the Fortune 500.
The LangSmith team owns the core platform for observability, evaluation, and production reliability of AI systems. As a Senior Fullstack Engineer, you will shape the technical direction of the platform while working closely with enterprise customers, developer end-users, and cross-functional stakeholders.
Key responsibilities include:
- Lead technical architecture and implementation of key product features across the Go, Python, and Typescript stack
- Collaborate closely with product and design teams to iterate on new features
- Drive aggressive project timelines while maintaining high engineering standards
- Lead by example in writing clean, maintainable, and well-tested code
This is a 5 days/week onsite role in Boston, MA.
REQUIREMENTS:
- 5+ years of software engineering experience on complex platform products
- Fullstack engineering experience: Go or Python backend, React + Typescript frontend
- Strong understanding of database systems, particularly Postgres and Redis
- Experience designing and scaling APIs in high-performance, data-intensive applications
- "Get stuff done" attitude; comfortable shipping fast and iterating based on user feedback
- Strong communication and collaboration skills with internal stakeholders and enterprise customers
- Strong ownership mindset
- Bonus: Experience with AI/LLM-powered applications, developer tools, or observability platforms
About LangChain
AI / Data / Infrastructure — developer platform and framework for building LLM applications and agents.
