Senior Backend Software Engineer, AI Observability & Evals Platform (NYC)

Langchain
New York, NY
On-site

In the 12 months to 30 Jun 2026, Langchain filed 6 H-1B positions titled "Software Engineer". Source: U.S. Department of Labor, LCA disclosure data. A record of filings already made, not a commitment to sponsor.

Who this role is best for

A natural match if you have experience building high-throughput systems with Python or Go in the AI observability domain.

Best fit for

  • Individuals who have shaped production-scale AI systems through architectural decisions
    — “Collaborate on architectural decisions to ensure systems are performant and maintainable”
  • Professionals with a history of optimizing data services for performance and reliability
    — “Demonstrated ability to optimize backend services for performance and reliability”

Things to consider

  • This role requires in-office presence for at least three days per week in New York.
    — “meals on in-office days in the US”
  • The position demands ownership of system reliability and long-term fixes.
    — “Troubleshoot and resolve production issues, performing root-cause analysis and implementing long-term fixes”

How to stand out

  • Emphasize your experience with observability tools and large-scale AI evaluation systems.
    — “building the backend systems that power LangChain’s observability and evals platform”
  • Highlight your track record in optimizing storage and query performance for high-volume data.
    — “Optimize storage and query performance for high-volume observability and evaluation data”
  • Showcase your ability to create technical documentation and maintain API references.
    — “Create and maintain technical documentation, including system design and API references”
  • Demonstrate your cross-functional collaboration on feature rollouts with full-stack teams.
    — “Work closely with full-stack engineers, product managers, and product designers on rolling out new features”
Pace · SteadyCollaboration · HighAutonomy · MediumDecision Impact · Team

Derived from job-description analysis by Serendipath's career intelligence engine.

What success looks like

  • design, develop, and maintain backend services and APIs for LangSmith’s tracing, monitoring, and evaluation workflows
  • optimize storage and query performance for high-volume observability and evaluation data
  • ensure system reliability through strong testing, monitoring, and alerting practices
Typical background
5+ years of professional experience in backend engineeringproficiency in Python or Gostrong understanding of API design and building reliable data services

Skills & requirements

Required

Backend EngineeringAPI DesignHigh-throughput SystemsMission-critical SystemsDatabase SystemsCloud PlatformsPerformance TuningDebugging Production IssuesTechnical Documentation

Preferred

Fullstack EngineeringFrontend EngineeringPerformance TuningDebugging Production Issues

Stack & domain

Backend EngineeringAPI DesignDatabase SystemsCloud PlatformsPerformance TuningDebugging Production IssuesAI ObservabilityEvaluationProduction Reliability

About the role

Original posting from Langchain via Ashby

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

We are looking for a Senior Backend Engineer to join us. In this role you will be 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.

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

  • 5+ years of professional experience in backend engineering working on highly complex products
  • 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

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.

We are hiring for this role across a range of scope, and the compensation band reflects that. Your offer depends on what we learn about your impact, craft, leadership, and communication during the interview process. We will tell you early where you’re tracking and talk comp with you before offer stage. 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.

Source: Langchain careers (Ashby)

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