Backend Engineer, Observability & Evals Platform (LangSmith)

LangChain•Cambridge, MA

2d•Hybrid

About The Position

We are looking for a Backend Engineer to join our LangSmith team. In this role, you will be responsible for designing and building the backend systems that power LangChain’s observability and evals platform. You will work on the core services that allow developers to monitor and evaluate their AI applications at scale. While the focus is on backend feature development, familiarity with fullstack or frontend engineering, performance tuning, and debugging production issues would be extremely valuable. This role is based in our San Francisco, New York, or Boston office. Employees within commuting distance work from the office five days per week. Candidates who live outside commuting distance (e.g. >1hr each way), may be eligible for hybrid arrangements depending on location and role requirements.

Requirements

2+ years of professional experience in backend engineering
Proficiency in backend languages/frameworks, ideally Python or Go
Strong understanding of API design and building reliable data services.
Experience with high-throughput or mission-critical systems.
Demonstrated ability to optimize backend services for performance and reliability.
Experience with database systems (Postgres, Redis, Clickhouse), and cloud platforms (AWS, GCP, Azure)
Strong communication skills, with the ability to collaborate cross-functionally
Customer centricity and ownership mentality

Responsibilities

Design, develop, and maintain backend services and APIs to support LangSmith’s tracing, monitoring, and evaluation workflows.
Collaborate on architectural decisions to ensure systems are performant and maintainable.
Optimize storage and query performance for high-volume observability and evaluation data.
Ensure system reliability through strong testing, monitoring, and alerting practices.
Troubleshoot and resolve production issues, performing root-cause analysis and implementing long-term fixes.
Create and maintain technical documentation, including system design and API references.
Work closely with full-stack engineers, product managers, and product designers on rolling out new features.