About Lang Chain:

At Lang Chain, our mission is to make intelligent agents ubiquitous. We provide the agent engineering platform and open source frameworks developers need to ship reliable agents fast.

Our open source frameworks, Lang Chain and Lang Graph, see over 90+ million downloads per month and help developers build agents with speed and granular control. Lang Smith offers observability, evaluation, and deployment for rapid iteration, enabling teams to transform LLM systems into dependable production experiences.

Lang Chain is trusted by millions of developers worldwide and powers AI teams at companies like Replit, Clay, Cloudflare, Harvey, Rippling, Vanta, Workday, and more.

About the role:

Lang Chain 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, San Francisco, or Boston.

What you will do:

• Work across our stack (React, TypeScript, Python, Go) to deliver full-stack product features that drive growth and retention
• Build flexible experimentation systems and processes capable of targeting diverse growth metrics
• Participate in data-driven, rapid growth experiments across the user funnel from onboarding to monetization
• Design and ship new onboarding features and improvements that accelerate time to value
• Build growth levers including usage-based guardrails, smart upgrade triggers, and contextual CTAs
• Collaborate closely with product, design, GTM, and analytics teams to identify, prioritize, and execute high-impact growth opportunities

How to be successful in this role:

• Extensive fullstack software development experience using React, TypeScript, and Go and/or Python
• Strong product intuition and a track record of working on monetization, pricing, or activation features
• Familiarity with usage metering, subscriptions, and internal tooling for pricing experiments
• Comfortable working with REST APIs, Postgres, Redis, and modern backend infra
• Startup DNA with the ability to thrive in fast-paced, zero-to-one environments
• Self-directed with an ownership mindset
• Bonus: Experience building for developers or product-led growth platforms
• Bonus: Familiarity with LLMs, GenAI applications, or agentic frameworks

Compensation: We offer competitive compensation that includes base salary, meaningful equity, and benefits such as health and dental coverage, flexible vacation, a 401(k) plan, and life insurance. Actual compensation will vary based on role, level, and location. For team members in the EU and UK, we provide locally competitive benefits aligned with regional norms and regulations.

Salary Range: $175,000-$225,000 USD