Software Engineer, Monetization Platform

About the role

At Simular we are building AI agents that operate computers to help people and businesses get work done. As the product scales, we need reliable commercial systems for product access, pricing, and revenue. You will build the backend foundation that turns customer accounts and product usage into clear plans, accurate bills, successful payments, and correctly provisioned access.

Key responsibilities

• Own the domain models and APIs for customer accounts, organizations, workspaces, plans, pricing, trials, seats, and entitlements.
• Build subscription and usage‑based billing systems, including metering, aggregation, invoicing, credits, proration, upgrades, downgrades, cancellations, and recovery flows.
• Integrate Stripe and future payment providers across checkout, recurring payments, payment failures, refunds, disputes, and provider webhooks.
• Design robust payment and billing state machines that are idempotent, replay‑safe, observable, and resilient to duplicate, delayed, or out‑of‑order events.
• Build trustworthy financial records, reconciliation workflows, audit trails, and internal tools for resolving account and billing exceptions.
• Partner with product and customer‑facing teams to translate commercial requirements into simple, maintainable systems and customer experiences.
• Set a high bar for correctness and operational ownership where a wrong charge or missing entitlement directly affects customer trust.

Required profile

• BS/MS in Computer Science or equivalent experience and 5+ years of backend engineering experience.
• Built production systems for B2B SaaS, e‑commerce, fintech, or other transaction‑heavy products.
• Hands‑on experience with Stripe or a comparable payment provider, including webhooks and payment lifecycle handling.
• Ability to model complex business domains such as accounts, subscriptions, orders, invoices, payments, usage, and entitlements.
• Understanding of idempotency, transactional consistency, money precision, reconciliation, auditing, and safe data migration practices.
• Strong with relational databases and production API design, reasoning about correctness under retries and partial failures.
• Bias for action, clear communication, and enjoyment of owning an ambiguous 0‑to‑1 domain end‑to‑end.

Required skills

• Stripe
• Relational databases
• API design