Senior Fullstack Engineer, AI Observability & Evals Platform

Senior Fullstack Engineer 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 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 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 include medical, dental, and vision coverage, flexible vacation, a 401(k) plan, meals on in-office days in the US and more.