LangChain
Senior Backend Software Engineer, AI Observability & Evals Platform (LangSmith)
- Compensation
- $180K–$240K / yr
- From job posting
- Location
- Cambridge, MA, US
- Arrangement
- On-site
- Employment type
- Full-time
- Level
- Senior
- Posted
- 12 September 2026 (18 days ago)
Checked 18 days agoApplications go to the employer, never to RoleSprint
About this role
ABOUT US
At LangChain, our mission is to make intelligent agents ubiquitous. We build the foundation for agent engineering in the real world, helping developers move from prototypes to production-ready AI agents that teams can rely on. We began as widely adopted open-source tools and have grown to also offer a platform for building, evaluating, deploying, and operating agents at scale.
With $125M raised at Series B from IVP, Sequoia, Benchmark, CapitalG, and Sapphire Ventures, we’re at a stage where we’re continuing to develop new products, growth is accelerating, and all team members have meaningful impact on what we build and how we work together. LangChain is a place where your contributions can shape how this technology shows up in the real world.
Today, our platform includes LangSmith (Observability, Evaluation, Deployment, Fleet, and Sandboxes), our open source frameworks (LangChain, LangGraph, and Deep Agents), and the newly launched LangSmith Engine for autonomous agent improvement. We have 100M+ monthly open source downloads, 6,000+ active LangSmith customers, and 5 of the Fortune 10 use LangSmith in production (+ 35% of the Fortune 500 overall), including teams at Klarna, Clay, Coinbase, Workday, Lyft, Cloudflare, Harvey, Rippling, Vanta, LinkedIn, Monday.com, Nvidia, and Bridgewater.
ABOUT THE TEAM
The LangSmith team owns and builds LangChain's core platform for observability, evaluation, and production reliability of AI systems. From tracing and annotation to run rules, evaluations, and beyond, this team owns LangSmith end-to-end. If you want to define what great AI observability looks like at production scale, this is where that work gets done.
ABOUT THE ROLE
This role is based onsite in Boston, MA.
We are looking for a Senior Backend Engineer to join our growing engineering team in Boston. In this role you will be building the backend systems that power LangSmith, LangChain’s observability and evals platform. You will work on the core services that allow our customer's developer teams 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 valuable.
WHAT YOU'LL 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.
WHAT YOU'LL BRING:
- 4+ years of professional experience in backend engineering working on highly complex products
- Proficiency in one or more backend languages/frameworks, ideally Python and/or Go
- Strong understanding of API design and building reliable data services.
- Experience with high-throughput, 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) would be a bonus.
- Strong communication skills, with the ability to collaborate cross-functionally.
- Customer centricity and ownership mentality
Compensation:
Annual salary range: $180,000- $240,000
Compensation Philosophy:
We offer competitive compensation that includes base salary, variable compensation for relevant roles, meaningful equity, benefits, and perks. Actual compensation and offerings will vary based on role, level, and location. Team members in the EU, UK, and APAC receive locally competitive benefits aligned with regional norms and regulations.
BENEFITS
Benefits include medical, dental, and vision coverage, flexible vacation, a 401(k) plan, meals on in-office days in the US and more.
Locations
- Cambridge, MA, US
- New York, NY, US
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About this listing
Advertised by Langchain and published on Ashby, the applicant tracking system they use.
RoleSprint is not the employer and not a recruiter. Applications are made on the employer’s own site and never reach us; what RoleSprint does is help you decide whether a role is worth your time and prepare for it if it is.
Published 12 September 2026, last checked 18 days ago. A posting stops being advertised here 90 days after the employer published it, and one the employer takes down is marked closed rather than quietly removed.