Software Engineer, Payments

Aiwyn is the first complete platform for modern Accounting Firms, backed by top-tier investors and one of the fastest-growing scale-up SaaS companies. They are seeking a Senior Software Engineer to join the team that owns their payments platform, responsible for building systems that manage the full payment lifecycle and ensuring reliable money movement.

Responsibilities:

• Build the systems that move money reliably. Own the services, infrastructure, and confidence metrics that let payments grow at speed without sacrificing accuracy or trust. Make the iteration loop faster every cycle
• Work in the trenches with the domain experts. They've been doing this for decades. They're your closest collaborators and your toughest users. Spend real time with them, understand what it actually takes to invoice, collect, and reconcile across firms and jurisdictions, and translate that depth into the systems you build
• Build and extend the APIs that Aiwyn, firms, and partners build on top of. Integrations are the wedge. Make connecting payment processors, banks, and firm systems seamless, and the surface area something engineers actually want to use
• Take projects from spec to ship to scale. Own the work end to end, including the parts outside your comfort zone

Requirements:

• 5+ years of professional software engineering experience, with a track record of taking full ownership of the projects you take on
• Hands-on technical depth in domains where correctness matters. You've shipped real systems where edge cases, accuracy, and domain depth were non-negotiable
• Experience with fintech and payments. Direct work on payment systems, money movement, or collections. You understand why getting money movement right is non-negotiable, and you've shipped systems where that showed
• Demonstrated ability to bridge engineering and a non-engineering domain. Engineers and finance/accounting experts (or doctors, or lawyers, or any deep domain expert) think wildly differently. You've worked closely with non-engineering experts before, taken their judgment seriously, and built shared language and shared artifacts that let both sides do their best work. We've watched smart people struggle here, and this is the part of the job we look at hardest
• AI-native fluency. AI tooling is woven into how you work and ship, and you have a clear point of view on where it helps and where it creates noise
• Comfortable across the stack. Backend, frontend, or infrastructure — you can reason about whatever the problem actually requires
• Bonus: deeper fintech and/or payments experience. Building or contributing to a payments, billing, ledger, pricing, underwriting, claims adjudication, compliance, or benefits system — anywhere correctness is non-negotiable and the system has to compose hundreds or thousands of rules into an answer you can defend. Payments specifically in the accounting industry is the strongest plus of all, but none of this is required