FullStack Engineer, Observability & Evals Platform (LangSmith)

Langchain; Town of Boston (NY); On-site; USD 145,000 - 180,000; Full time

Benefits offered by this job

Medical, dental, and vision

401(k) plan

In-office meals

Flexible vacation

Job summary

LangChain is seeking a Fullstack Engineer to advance LangSmith, our AI observability and evals platform. You will build new features across Go, Python, and Typescript, engaging with enterprise customers and developers.

You will collaborate with product and design teams, own end-to-end features, and maintain high quality, scalable APIs. Prior experience with modern stacks and a customer-focused mindset is essential. This role offers impact across the product lifecycle and a fast-growing team.

Qualifications

• 2+ years of software engineering with complex platform products.
• Fullstack experience: Go or Python on backend and React + Typescript on frontend.
• Strong DB knowledge: Postgres and Redis.
• Experience designing and scaling APIs; ownership and delivery focus.

Responsibilities

• Develop and implement key features across Go, Python, and TypeScript stack.
• Collaborate with product and design to refine features and roadmap.
• Maintain high engineering standards with clean, well-tested code and timely delivery.

Skills

Go

Python

React

Typescript

PostgreSQL

Redis

APIs design

Ownership mindset

Communication

Job description

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. 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.