Senior Frontend Engineer
Confirmed on the employer's own hiring board on Sep 25, 2026. First seen by Alion on Sep 24, 2026. LangChain scores A on the Alion truth index.
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
(Onsite in Boston)
We’re looking to bring on an experienced frontend engineer to develop and enhance new features on LangSmith, our enterprise platform product for LLM application observability, testing, and debugging.
What You Will Do
Develop new user-facing features using React & Typescript
Build reusable components and front-end libraries for future use
Translate designs and wireframes into high-quality code
Optimize components for maximum performance across a vast array of web-capable devices and browsers
Collaborate with fullstack and backend developers and UX/UI designers, to enhance usability
What You Will Bring
Extensive front-end engineering experience with strong proficiency in React, JavaScript and TypeScript
Hands-on experience with front-end development tools like Babel, Vite, Webpack, NPM, and Yarn
Familiarity with REST APIs and experience working closely with fullstack and backend engineers
Knowledge of modern authorization mechanisms, such as JWTs
A passion for user experience, design and building clean, engaging, and intuitive interfaces
Strong written and oral communication skills, with the ability to explain technical concepts clearly and concisely to both technical and non-technical stakeholders
The DNA to thrive in a start-up, fast-paced environment. Views unstructured environments as an opportunity to figure out the most impactful work and help define the future success of the company
An ownership mind-set. You are self-driven and look for opportunities to make an impact.
Strong computer science fundamentals, ideally with a degree in computer science or related field
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. 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.