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 Growth & Monetization team focuses on how developers discover, adopt, and scale with LangChain’s products. We work across the full stack to improve onboarding, activation, and usage while building the systems that power billing, pricing, and monetization. This team partners closely with product, design, and go-to-market teams to understand developer behavior and translate those insights into product improvements that drive adoption and revenue. Our work directly shapes how developers and organizations move from experimentation to production on the LangChain platform. About the role LangChain is hiring a Senior Fullstack Engineer to build the foundational product features and integrations that power user acquisition, rapid experimentation, and self-serve expansion. This is a high-impact 0→1 role on a newly formed team responsible for building growth systems from the ground up. You’ll work closely with product, design, GTM, and analytics to streamline activation, optimize packaging, and deliver a seamless growth story for developers and enterprise customers alike. This role will be in person 5 days/week in New York City. What you'll do - Lead projects across our stack (React, TypeScript) while working with backend APIs (Python, Go) - Build polished, responsive user interfaces for onboarding, self-serve upgrades, and usage dashboards that delight users - Design and execute rapid, client-side UI experiments (A/B tests, feature flags) targeting key activation and conversion metrics - Partner with Product and Design to translate complex user journeys into simple, intuitive web experiences - Implement clean client-side event tracking and behavioral analytics to understand developer journeys - Build growth levers, including smart upgrade triggers, usage notifications and personalized, contextual experiences What you'll bring - Strong mastery of modern frontend development (React, TypeScript, CSS/Tailwind) - Solid fullstack fundamentals (working with REST/GraphQL APIs, Python/Go backends, database querying and caching) - Exceptional UX intuition and a sharp eye for visual polish, micro-interactions, and developer-focused user journeys - Experience building or optimizing frontend growth engines (e.g., onboarding wizards, conversion funnels, checkout flows, A/B testing frameworks, usage metering, subscriptions) - Startup DNA with a desire to ship fast, iterate based on user data, self-directed and take end-to-end ownership - Bonus: Experience building tools for developers, PLG SaaS platforms, or design systems - Bonus: Familiarity with LLMs, GenAI applications, or agentic frameworks Compensation - Salary Range: $165,000-$250,000 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.