Senior Payments Engineer

Why Polar? It's never been easier to build, ship and scale software. But it's never been harder to monetize it. Modern startups look fundamentally different than prior generations: Smaller teams Exponential revenue growth relative to headcount Higher variability in costs (LLMs) requiring more frequent pricing iterations Laser focused on product development and distribution Delegating and automating everything that is boilerplate – be it in their codebase or business operations. Exceptional billing primitives, APIs and SDKs are essential, but delightful integration is not enough. Startups need a billing platform designed for their speed of iteration. Combining billing and analytics in one platform to offer customer- and feature unit economics in real-time. Offering built-in pricing and cost insights, simulations and optimizations while simultaneously handling international compliance, tax management, fraud prevention and more. That's Polar. We're building the next standard for applied AI startups. Join our small, talented and engineering-led team across Europe as we build the infrastructure powering the next generation of software companies. We focus on shipping at high velocity to serve startup founders scale their businesses. Everything else is secondary. Role & responsibilities: What you will do We’re hiring a Senior Payments Engineer to advance the payments and billing infrastructure that powers Polar’s platform and strengthen the financial backbone of the company. Your focus will be to bring depth and rigor to our payments and billing systems, operating around critical product surfaces - subscription billing, transaction flows, tax calculation, payouts, risk controls and financial reporting - ensuring they are scalable, reliable and architected for long-term growth. While also building, scaling and optimizing our global payment orchestration infrastructure. Polar operates as a merchant of record, meaning we take on the complexity of global payments, tax compliance and financial reporting on behalf of developers. This role is perfect for someone who combines strong product intuition with deep payments systems thinking and who understands that in financial infrastructure correctness, resilience and clarity are non-negotiable. You’ll work with the team to: Strengthen Our Payments & Billing Architecture: Partner with the team to design and evolve subscription logic, pricing models, invoicing, transaction flows, refunds, disputes and payouts - while introducing rigorous financial systems thinking around idempotency, state management, ledger integrity, reconciliation, settlement consistency and failure handling to ensure correctness across the full payment lifecycle. Build Merchant-facing Payment Experiences: Design and ship intuitive dashboards, onboarding flows, billing configuration and APIs - backed by robust payment primitives and backend infrastructure. Improve Reliability & Observability: Strengthen monitoring, testing and rollback mechanisms for critical financial flows. Ensure we can detect inconsistencies, reconciliation issues and failures quickly and resolve them safely. Collaborate Across Product & Compliance: Work closely with product, support and legal to translate regulatory requirements and acceptable use constraints into well-designed enforcement systems. Evolve our PSP & Infrastructure Integrations: Refine how we integrate with payment service providers and external financial partners, designing abstractions that reduce coupling while maintaining flexibility across payment methods, regions and providers. What we’re looking for Systems Thinking & Operating Mindset Deep systems thinking - you anticipate failure modes, design for idempotency and consistency, and model state transitions explicitly in money movement systems. Security- and compliance-aware engineering mindset - you build with auditability, principled access control and regulatory constraints as first-order design considerations. Strong product judgement - you know when to move fast while ensuring that correctness, auditability and long-term system integrity take precedence. Strong merchant empathy. You build intuitive merchant-facing experiences with attention to usability, performance, and design detail. High ownership and collaborative mindset. Comfortable operating in small, high-ownership teams. You collaborate deeply, influence architectural direction and take responsibility for outcomes, not just code. Technical skills Strong backend expertise. You design clear, durable APIs and build systems that are resilient under real-world load and edge cases. Highly proficient in SQL and data modeling - you reason rigorously about financial reporting, reconciliation integrity and long-term data correctness. Strong production debugging and observability instincts with an ability to trace inconsistencies across financial workflows, APIs and service boundaries with confidence. Experience 5-8+ years of engineering experience, building and