ABOUT THE COMPANY Braintrust is the agent observability platform. By actively applying intelligence to agent traces and automatically surfacing the most critical patterns, Braintrust gives teams the visibility to understand how agents behave in production and the tools to improve them. Teams at Notion, Stripe, Box, OpenAI, and Cloudflare use Braintrust to trace their agents, find the issues in their observability data, and run evals that tell them how to improve. ABOUT THE ROLE We’re looking for a Software Engineer, Billing to build the systems that make Braintrust’s pricing, usage, and payments accurate, scalable, and transparent. Braintrust helps teams observe, evaluate, and improve production AI agents. Our customers generate large volumes of traces, run automated and human evaluations, use AI-powered product features, and retain data under different plans and policies. Billing needs to turn those product activities into clear, reliable customer experiences—from usage measurement and plan enforcement to invoices, credits, and account state. You’ll work across the billing stack: usage metering, subscriptions and entitlements, payment integrations, invoicing, credits, and the internal systems that reconcile them. This is a deeply technical IC role. It is not a finance-operations role, and it is not a backend generalist role that contributes to billing occasionally. You’ll be a technical authority on billing correctness and scale, helping Braintrust launch pricing models that let customers adopt the platform with confidence as their AI workloads grow. WHAT YOU'LL DO Core responsibilities: - Own Braintrust billing architecture end-to-end, including metering, plans, subscriptions, entitlements, invoices, credits and payments. - Design our billing architecture to solve immediate needs and simplify billing for new features as they are developed and released. - Ensure Braintrust accurately measures and bills for product usage, including processed data, evaluation scores, model usage, and data retention. - Partner with product, infrastructure, finance, and customer-facing teams to introduce new pricing models and billing workflows with confidence. Build the systems that power Braintrust billing, such as: - A reliable usage-metering and aggregation pipeline that turns product activity into accurate customer usage. - A subscription, limits, and entitlement system that supports plan allowances, feature access, trials, upgrades, and on-demand usage. - Internal tools and APIs for investigating billing anomalies, issuing credits, and helping customers understand their account state. - Observability across the billing pipeline, including metering lag, event completeness, reconciliation discrepancies, and payment health. IDEAL CANDIDATE CREDENTIALS - Expert-level understanding of TypeScript, Rust, SQL, backend systems, APIs, and distributed data-processing patterns - Experience building and operating production usage-based billing, payments, or subscription systems - Experience with metering, aggregation, idempotency, reconciliation, and event-driven architectures - Experience integrating with Stripe or similar payment infrastructure - Experience building or maintaining financial ledgers, credits, balances, or invoice systems is a plus - Comfortable shipping end-to-end, from backend infrastructure and data systems to internal tools and customer-facing UI - Previous experience founding or working at startups is a plus - Has an appreciation for the tension between moving quickly and preserving customer trust and billing correctness BENEFITS INCLUDE - Medical, dental, and vision insurance - Daily lunch, snacks, and beverages - Flexible time off - Competitive salary and equity - Wifi & cellphone stipend EQUAL OPPORTUNITY Braintrust is an equal opportunity employer. All applicants will be considered for employment without attention to race, color, religion, sex, sexual orientation, gender identity, national origin, veteran or disability status.