Software Engineer, Monetization Platform

Where multiple locations are listed for this role, the position may be based in any of those locations, with priority determined according to the order of listing. At Simular, we are building AI agents that operate computers to help people and businesses get work done. As our product reaches more customers, we need the commercial systems that make product access, pricing, and revenue reliable. You will build the backend foundation that turns customer accounts and product usage into clear plans, accurate bills, successful payments, and correctly provisioned access. This is a SaaS monetization role focused on accounts, subscriptions, billing, payments, and entitlements. It is not an ads monetization role, and it is not primarily a cloud infrastructure or agent-runtime role. What You'll Do Own the domain models and APIs for customer accounts, organizations, workspaces, plans, pricing, trials, seats, and entitlementsBuild subscription and usage-based billing systems, including metering, aggregation, invoicing, credits, proration, upgrades, downgrades, cancellations, and recovery flowsIntegrate Stripe and future payment providers across checkout, recurring payments, payment failures, refunds, disputes, and provider webhooksDesign robust payment and billing state machines that are idempotent, replay-safe, observable, and resilient to duplicate, delayed, or out-of-order eventsBuild trustworthy financial records, reconciliation workflows, audit trails, and internal tools for resolving account and billing exceptionsPartner with product and customer-facing teams to translate commercial requirements into simple, maintainable systems and customer experiencesSet a high bar for correctness and operational ownership in systems where a wrong charge or missing entitlement directly affects customer trust You might be a fit if You have a BS/MS in Computer Science or equivalent experience and 5+ years of backend engineering experienceYou have built production systems for B2B SaaS, e-commerce, fintech, or another transaction-heavy productYou have hands-on experience with Stripe or a comparable payment provider, including webhooks, payment lifecycle events, and failure handlingYou can model complex business domains such as accounts, subscriptions, orders, invoices, payments, usage, and entitlementsYou understand idempotency, transactional consistency, money precision, reconciliation, auditing, and safe data migration practicesYou are strong with relational databases and production API design, and you can reason clearly about correctness under retries and partial failuresYou have a bias for action, communicate clearly, and enjoy owning an ambiguous 0 to 1 domain end-to-endBonus: experience with usage-based billing, revenue operations, tax or invoicing systems, multi-currency payments, or financial ledgers