Senior Fullstack Engineer, AI Observability & Evals Platform
Role summary
LangChain is seeking a Senior Fullstack Engineer for its commercial product, LangSmith, an AI observability and evals platform. This role is based in San Francisco and requires 5 days/week in-office. The engineer will lead technical architecture and implementation across the Go, Python, and Typescript stack, collaborating with product and design teams. Responsibilities include mentoring junior engineers, driving project timelines, and maintaining high engineering standards. The ideal candidate has 7+ years of experience, fullstack expertise with Go/Python backend and React/Typescript frontend, strong database knowledge (Postgres, Redis), and experience scaling APIs. Familiarity with AI/LLM applications is a plus.
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.
Today,
LangChain, LangGraph, LangSmith, and Agent Builder
are used by teams shipping real AI products across startups and large enterprises. Millions of developers trust LangChain to power AI teams at companies like
Replit, Clay, Coinbase, Workday, Lyft, Cloudflare, Harvey, Rippling, Vanta, and 35% of the Fortune 500
.
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.
About the role:
In person 5 days/week in San Francisco
We're looking for a Senior Fullstack Engineer for our commercial product LangSmith, an observability and evals platform. In this role, you'll have the opportunity to shape the technical direction of our platform while working closely with enterprise customers, developer end-users and internal stakeholders.
- Lead the technical architecture and implementation of key product features for LangSmith, working across our entire Go, Python, and Typescript stack.
- Collaborate closely with product and design teams to iterate on new features.
- Mentor and guide more junior members of the team. Drive aggressive project timelines while ensuring high engineering standards are being met.
- Lead by example in writing clean, maintainable, and well-tested code
How To Be Successful In This Role
- 7+ 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.
- Strong understanding of database systems, particularly Postgres and Redis
- Experience designing and scaling APIs, preferably in a high-performance, data-intensive application
- A “get stuff done” attitude - 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
- Strong ownership mindset
- Bonus: Experience with AI/LLM-powered applications, developer tools, or observability platforms
Compensation & Benefits
- We offer competitive compensation that includes base salary, meaningful equity, and benefits such as health and dental coverage, flexible vacation, a 401(k) plan, and life insurance. Actual compensation will vary based on role, level, and location. For team members in the EU and UK, we provide locally competitive benefits aligned with regional norms and regulations.
- Annual salary range: $175,000-$225,000 USD