Senior Backend Engineer, Enterprise Monetization Infrastructure (AI)

Location: In-person 5 days per week in San Francisco, United States

Annual salary: $175,000–$240,000

Company

LangChain builds open-source frameworks and a platform for developing, evaluating, deploying, and operating production-ready AI agents.

What you will do

• Rearchitect the billing pipeline into a self-serve platform for launching new pricing models.
• Design and implement usage-based and token-based pricing infrastructure in Python and Go.
• Build shared primitives and abstractions for configurable pricing models and SKUs.
• Implement audit logging, usage tracking, and metering pipelines focused on billing correctness.
• Integrate with Metronome, Orb, Stripe, and other billing or payment platforms.
• Own reconciliation, deduplication, proration, disputes, and credits while partnering with product and enterprise engineering teams.

Requirements

• 5+ years of backend engineering experience with Python or Go; experience with both is preferred.
• Hands-on experience building or scaling usage-based, subscription, or consumption billing infrastructure.
• Experience with metering, invoicing, or configurable pricing-model logic.
• Familiarity with Postgres, Redis, APIs, and modern distributed backend infrastructure.
• Strong ownership and ability to work in a fast-paced, unstructured startup environment.
• Ability to work onsite in San Francisco five days per week.

Nice to have

• Experience with token-based or usage-based cost tracking, especially at LLM or API-first companies.

Culture & Benefits

• Meaningful impact on products and engineering practices during a high-growth stage.
• Medical, dental, and vision coverage.
• Flexible vacation.
• 401(k) plan and meals on in-office days in the US.
• Base salary, variable compensation where relevant, equity, and additional perks.