Senior Backend Engineer, Enterprise Billing Platform

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 Enterprise Readiness team builds the systems that allow large organizations to securely adopt and scale LangChain in production. Within that team, this role sits on the billing and monetization pod, responsible for the pricing infrastructure that powers how LangChain charges for usage across every product, from simple per-trace billing to complex, configurable enterprise pricing models.   LangChain is hiring a Senior Backend Engineer, Enterprise Monetization Infrastructure to rebuild and scale the systems behind how we price and bill for usage. Today's billing pipeline gets the job done. The next step is making it a genuine strength: a flexible, self-serve platform that lets any team at LangChain launch a new pricing model in days instead of weeks, without needing to understand the internals. This is a high-impact, newly formed role reporting into the Enterprise Readiness team. You'll partner closely with the billing PM, enterprise engineering, and product teams across LangChain to define the primitives and architecture that make pricing fast, flexible, and accurate at scale, including the added complexity of usage-based and token-based pricing for AI products. Location: In-person 5 days/week in San Francisco.   What You'll Do - Rearchitect LangChain's billing pipeline into a self-serve platform, building the primitives and components other engineering teams use to launch new pricing models without needing enterprise team review - Design and implement usage-based and token-based pricing infrastructure (Python/Go), including complex, configurable pricing logic beyond simple per-unit charging - Build the underlying system that will eventually power an internal agent and skills interface, letting teams describe a pricing model and go live in days instead of weeks - Reduce the code and complexity required to ship a new pricing SKU through better abstractions and shared components - Implement audit logging, usage tracking, and metering pipelines tied to billing accuracy, with a focus on correctness as pricing complexity increases - Integrate with billing and payment platforms (e.g. Metronome, Orb, or Stripe) to support metering and invoicing - Own billing reconciliation, deduplication, and edge cases like proration, disputes, and credits to ensure invoicing accuracy at scale - Partner with the billing PM and enterprise engineering to define and prioritize the pricing infrastructure roadmap - Write clean, maintainable, and well-documented backend code   What You'll Bring - Technical experience - 5+ years of backend engineering experience with Python or Go (both preferred) - Hands-on experience building or scaling usage-based, subscription, or consumption billing infrastructure - Experience with metering, invoicing, or pricing-model logic, ideally including work that let other teams configure or launch pricing changes themselves rather than requiring custom engineering per change - Familiarity with Postgres, Redis, APIs, and modern distributed backend infrastructure - Strong ownership mindset and ability to thrive in fast-paced, unstructured startup environments Nice to Have - Experience with token-based or usage-based cost tracking, especially from LLM/API-first companies Compensation - Annual salary range: $175,000- $240,000 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.