# Senior Backend Software Engineer, Observability & Evals Platform (LangSmith)

**Company:** [LangChain](https://hotfix.jobs/companies/langchain)
**Location:** Cambridge, MA, New York, NY, San Francisco, CA
**Role:** Backend Engineering
**Salary:** $175k – $225k/yr
**Experience:** 5+ years
**Skills:** Python, Go, Postgres, Redis, ClickHouse, AWS, GCP, Azure, API Design, Kubernetes
**Posted:** 2026-01-08

> Senior Backend Engineer builds and optimizes services for LangSmith's observability and evaluation platform, handling high-volume AI app monitoring. Requires 5+ years experience, Python/Go proficiency, database expertise, and performance optimization skills.

## Job Description

## What you will do:
- 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.

## How to be successful:
- 5+ years of professional experience in backend engineering
- Proficiency in one or more 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

## Compensation & Benefits
Annual salary range: **$175,000-$225,000**. Competitive compensation includes base salary, meaningful equity, health/dental coverage, flexible vacation, 401(k), and life insurance.

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