Senior Software Engineer, Payments

About the Role

Remitian is looking for a high-agency Staff Software Engineer to join our Payments team and own the systems that move money on our platform. The Payments team owns everything from a tax obligation becoming a payment through to the ledger that records every transaction: banking integrations and fee charges, automated payment integrations with tax authority portals, support for new payment types and tax authorities as the platform expands, and the subscription system for taxpayers and firms. Its mission is to make tax payments reliable, traceable, and effortless, no matter the payment type or tax authority behind it.

This is a staff-level role, which means your scope spans the payments platform rather than a single feature area. You will work closely with the Payments team lead and the rest of the team on the design of our money-movement systems, contribute to the standards and patterns we build on, and help deliver work that reaches across team boundaries. You will write a lot of code, and you will add leverage through the design decisions you shape and the engineers you help grow along the way.

You will work across the stack, from data models and services through to the surfaces our customers and internal teams use. We are looking for someone who has built money-movement systems before and knows the difference between a payment flow that works on the happy path and one that stays correct, traceable, and recoverable when the real world intervenes.

This role is based in Florida, with Miami preferred, on a hybrid schedule of 3 to 4 days per week in office.

Key Responsibilities

Payments Domain Ownership

• Own money-movement workflows end to end, from a tax obligation becoming a payment through settlement and its record in the ledger
• Own the banking integrations, fee charges, and transaction ledger that keep every movement of money accounted for
• Design and evolve our automated payment integrations with tax authority portals, and make them reliable, observable, and recoverable
• Drive support for new payment types and new tax authorities, turning each addition into repeatable patterns rather than one-off builds
• Treat idempotency, reconciliation, and exact accounting as first-class design constraints rather than afterthoughts

Technical Leadership and Architecture

• Lead the design of significant payments systems and see the architectural decisions behind them through to production
• Help shape technical direction for the Payments team alongside the team lead, and align it with the broader engineering roadmap
• Make and defend trade-offs around performance, scalability, security, correctness, and maintainability, and write those decisions down
• Contribute to the engineering standards, patterns, and best practices the team builds on, and hold the bar in code and design review
• Build alignment across teams on contracts and shared services, including the hard conversations that come with it

Full-Stack Product Development

• Design, build, and ship complex features across the stack, from data models and services through to UI
• Translate ambiguous requirements into clean, maintainable, well-tested systems
• Own the shared services other engineering teams depend on, and treat those teams as customers
• Partner with product, design, and engineering leadership to scope and deliver substantial bodies of work

Reliability, Security, and Production Operations

• Own payments services in production, including their reliability, performance, and operational behaviour
• Lead incident investigation and resolution, and drive the follow-up that prevents recurrence
• Set the standard for observability, alerting, and testing on critical money-movement workflows, where a silent failure is worse than a loud one
• Bring a security-first mindset to money movement, banking credentials, and sensitive taxpayer data in every review and design decision

Ownership, Mentorship, and Continuous Improvement

• Take real ownership of major areas of the payments platform and be accountable for their outcomes
• Identify problems, propose solutions, and drive them to completion without waiting for direction
• Mentor and grow other engineers through code review, pairing, and design feedback
• Contribute to engineering culture, hiring, onboarding, and standards as the team grows
• Push back, raise concerns, and surface ideas that improve the platform or how the team works

Who You Are

• 8+ years of experience as a software engineer, with a track record of designing and operating production systems at scale
• Proven experience building and operating payments or money-movement systems, such as ledgers, banking integrations, or payment rails, where correctness and reconciliation were part of your responsibility
• Deep, hands-on proficiency building production applications with C# and .NET, plus modern JavaScript or TypeScript
• Strong experience using LLMs and AI tooling to ship features and accelerate development
• Demonstrated ownership of non-trivial systems from architecture through production, including the operational consequences
• Strong systems-oriented judgement across performance, scalability, security, correctness, and reliability
• A track record of technical leadership without formal authority: aligning teams, mentoring engineers, and acting as a force multiplier
• High agency, meaning you find work that needs doing, take ownership, and move things forward without being told
• Excellent communicator, able to write a clear design document and explain trade-offs to engineers, executives, and non-technical audiences alike
• Excited by a fast-paced startup where priorities shift and ambiguity is part of the job

Nice to Haves

• Experience at a payments, banking, or financial infrastructure company where moving money was the product
• Hands-on experience with double-entry ledgers, reconciliation, or settlement systems
• Experience with RPA or browser automation at scale, and a feel for making integrations with brittle external portals dependable
• Hands-on experience with AWS and modern CI/CD pipelines at scale
• Security experience such as secure coding, threat modelling, or working in a regulated environment
• Experience with Blazor or other modern .NET front-end frameworks
• Experience with tax, compliance, or other domains where correctness is non-negotiable
• Interest in growing into an engineering management role over time, in addition to strong IC ability

Why Join Us

• Own the systems that move real money, where your design decisions show up in every payment the platform makes
• Join a high-performing team building mission-critical fintech infrastructure, and help shape where it goes technically
• Real staff-level scope: deep technical problems, architecture, and cross-team influence, not a bigger backlog
• Work on systems where correctness genuinely matters, since a wrong tax payment is not a cosmetic bug
• Use modern tools, including AI and LLM tooling, to move quickly and build with leverage
• Grow as a technical leader in a team that values high agency and ownership, with room to shape how the Payments team works as it scales