FullStack Engineer, AI Observability & Evals Platform (LangSmith)

Langchain
San Francisco +1 more
On-siteCareer-pivot friendly

In the 12 months to 30 Jun 2026, Langchain filed 12 H-1B positions classified as Software Developers. 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

Aimed at mid-to-senior Fullstack Engineers who are comfortable with enterprise product development and customer collaboration.

Best fit for

  • Candidates with experience in fullstack development across Go, Python, and Typescript, and a track record of working on enterprise platforms
    — “Develop and implement key product features working across our entire Go, Python, and Typescript stack”
  • Engineers who can balance speed with quality and take ownership of product features throughout their lifecycle
    — “Strong ownership and a 'get stuff done' mindset - comfortable shipping fast and iterating based on user feedback”

Things to consider

  • The role requires a high level of collaboration with product, design, and enterprise customers, which may demand strong interpersonal and communication skills.
    — “Collaborate closely with product and design teams to iterate on new features and enhance the product roadmap”
  • Candidates must be prepared to engage directly with top-tier customers, potentially requiring a high level of responsiveness and adaptability.
    — “Strong communicator with the ability to collaborate closely with various internal stakeholders and engage directly with our top-tier customers”

How to stand out

  • Highlight experience in fullstack development with Go/Python backend and React + Typescript frontend in your resume.
    — “Fullstack engineering experience with Go or Python on the backend and React + Typescript on the frontend”
  • Emphasize your ability to design and scale APIs in high-performance environments.
    — “Experience designing and scaling APIs, preferably in high-performance, data-intensive applications”
  • Demonstrate your experience with database systems, particularly with Postgres and Redis.
    — “Solid understanding of database systems, particularly Postgres and Redis”
Pace · Fast PacedCollaboration · HighAutonomy · MediumDecision Impact · Team

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

What success looks like

  • developed new features for LangSmith
  • enhanced product roadmap
  • implemented high-performance APIs
Typical background
software engineering experiencebackground in fullstack development

Skills & requirements

Required

Fullstack DevelopmentAPI DesignDatabase ManagementClean CodingUser Feedback Integration

Preferred

Ai/llm ApplicationsObservability Platforms

Stack & domain

GoPythonTypeScriptReactPostgreSQLRedisAPI DesignAi/llm-powered ApplicationsDeveloper ToolsObservability PlatformsCommunicationTeamworkLeadershipAIEngineeringPlatform Development

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 ROLE

We're looking for a Fullstack Engineer to work on LangSmith, our commercial AI observability and evals platform product. In this role, you'll have the opportunity to build new features and functionality for the platform while working close enterprise customers, developer end-users and internal stakeholders.

WHAT YOU WILL DO

  • Develop and implement key product features working across our entire Go, Python, and Typescript stack
  • Collaborate closely with product and design teams to iterate on new features and enhance the product roadmap
  • Drive aggressive project timelines while ensuring high engineering standards are being met by writing clean, maintainable, and well-tested code

HOW TO BE SUCCESSFUL IN THIS ROLE

  • 2+ years of experience in software engineering working on complex platform products
  • Fullstack engineering experience with Go or Python on the backend and React + Typescript on the frontend
  • Solid understanding of database systems, particularly Postgres and Redis
  • Experience designing and scaling APIs, preferably in high-performance, data-intensive applications
  • Strong ownership and a “get stuff done” mindset - comfortable shipping fast and iterating based on user feedback
  • Strong communicator with the ability to collaborate closely with various internal stakeholders and engage directly with our top-tier customers
  • Bonus: Experience with AI/LLM-powered applications, developer tools, or observability platforms

Compensation

Annual salary range: $145,000-180,000 USD

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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