Senior Software Engineer - Billing Platform

• As a Senior Software Engineer, you'll own critical backend systems that power our subscription, billing, and monetization flows-systems where correctness, auditability, and reliability are non-negotiable.
• You'll design and evolve our Quote-to-Cash stack, integrating with platforms like Dealhub, Stripe, Chargebee (or equivalents), and internal systems to ensure scalable, compliant, and data-consistent billing operations.

The role

• You'll be part of a fast-growing Engineering team of 250+ product developers, owning high-impact systems that directly affect revenue, customer experience, and operational efficiency.
• You will design and build backend services and APIs for subscription lifecycle management (plan changes, upgrades/downgrades, credits, refunds, invoicing), and define clean boundaries that enable smooth integrations with internal platforms (customer-facing portals, backoffice tools, ERP/CRM).
• You'll collaborate closely with Product, Finance, Sales, and Data teams to translate monetization requirements into robust technical solutions-balancing speed, correctness, and long-term maintainability.
• You'll take end-to-end ownership: from architecture and implementation to production operations, monitoring, reconciliation mechanisms, and continuous improvement.

Our stack & the day-to-day

• We predominantly use Ruby on Rails for the backend and React/React Native for clients, but you'll also have the opportunity to dive into Scala, Python, or any language best suited to build high-performance finance data services.
• You'll design production-grade APIs and event-driven workflows for billing operations, supporting asynchronous processes and integrations across multiple systems.
• You'll implement monitoring, alerting, and data integrity controls (reconciliation, audit logs, consistency checks) to detect and mitigate issues in payment flows and synchronization.
• You'll drive platform evolution and migrations: evaluating third-party providers, designing incremental migration strategies, validating data, planning rollbacks, and executing post-migration verification.
• You'll write RFCs, join in technical conversations, and share knowledge while mentoring less-experienced engineers.
• You'll iterate in short development cycles, running ephemeral dev environments to test and fail fast, all under a GitOps-driven mindset with CI/CD best practices.

Your first steps at Factorial

• Read a lot: Get to know Factorial's product, customers, and current Billing and monetization flows.
• Learn a lot: Pair with team members from different domains (Finance, Data, Product, Engineering) to understand the Quote-to-Cash landscape and where we need stronger systems.
• Code a lot: Contribute to quick wins in billing workflows and integrations-improving robustness, test coverage, and operational tooling.
• Fail a lot: We encourage experimentation. We understand that trying out new ideas, failing, and improving is part of the role.
• Talk a lot: Participate in team rituals and stakeholder sessions to ensure what we build is accurate, auditable, and solves real business needs., * First conversation with a Manager: a mix of human and technical topics, focused on how we can work together, to align expectations and review our Engineering Rubrics (check them out: they're open!) and salary range.
• Tech interview with Factorial engineers, discussing a piece of code you're proud of (or a mini-challenge). We want to see how you solve problems, not just lines of code.
• Final coffee-chat with our Director of Data to deep-dive into Factorial's culture, vision, and answer any questions you might have.
• All interviews are remote, using video conferencing tools!

Do you have experience in Scala?, * 3+ years of experience as a Software Engineer working on backend or platform systems.

• Solid experience designing and maintaining production-grade APIs and backend services.
• Proven ability to work with complex domain logic and data-sensitive systems, with a strong focus on correctness and long-term maintainability.
• Experience owning systems end-to-end, including production support, monitoring, and operational responsibility.
• Strong plus: experience with subscription platforms, recurring billing, payments, invoicing, or monetization systems.
• Strong plus: experience integrating with third-party billing/payment providers (Stripe, Chargebee, or similar) and/or ERP/CRM systems.
• Experience with event-driven systems, asynchronous workflows, and system integration patterns.
• Experience executing production migrations (including coexistence strategies), with validation, rollback planning, and post-migration verification.
• A strong ownership mindset, ability to navigate ambiguity, and clear communication with both technical and non-technical stakeholders.
• Comfortable working in English and with distributed teams.