Senior Fullstack Engineer - AI Observability & Evals Platform

About Us

At LangChain, our mission is to enable every company to own its intelligence. We believe agents will transform how companies operate, and we're building the foundation to make that future possible. Our open-source harnesses and LangSmith platform give developers and enterprises the infrastructure to run, improve, and govern agents at scale.

We've raised $460M to date, with our most recent funding round valuing the company at $3B, backed by leading investors including Sequoia, Benchmark, IVP, and CapitalG. As we continue to expand our platform and tackle some of the hardest challenges in agent engineering, every team member has the opportunity to make a meaningful impact and help shape both our technology and the future of the industry.

More than 7,000 organizations rely on LangSmith, from fast-growing startups to Fortune 500 enterprises, including NVIDIA, Bridgewater, LinkedIn, Workday, and Rippling. We're just getting started on making high-performing agents easier to build and manage at scale.

About Us:

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.

What You Will Do

• 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

What You Bring

• 5+ years of experiencein 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

• Annual salary range: $175,000-$240,000 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.