Senior Software Engineer (Node&React)

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. PRODUCT ENGINEERING AT POLAR Fullstack engineerings with a strong product sense and taste. As we grow, we'll gradually move towards more specialized roles between backend vs. frontend vs. product engineering. Therefore, we ask about your main strength in the application to ensure we maintain a strong & balanced team across the spectrum. OUR STACK * Frontend: React & Next.js with Tailwind CSS, Shadcn, TanStack Router and more. * Backend: Python (FastAPI), Postgres, Redis, Dramatiq. * Cloud: Vercel, Render & AWS. Always subject to change as we scale and new technologies emerge. ROLE & RESPONSIBILITIES We’re hiring exceptional Senior Product Engineers to join our growing remote-first team in Europe. You'll work across our entire stack to ship innovative features, enhancements and delights; obsessing over the developer experience and empowering them to scale their businesses. You're very comfortable jumping between frontend, backend, and infrastructure to autonomously identify, build, ship and scale features. We don't have a lot of meetings, red tape or code reviews. We celebrate and optimize our organisation for shipping high-quality software fast – each engineer deploys countless times a day. So you'll be given a lot of agency and autonomy to move fast towards our mission and serving our developer community. * Ship daily towards building the best monetization platform for developers in the world. * Design, build, and ship features, enhancements and delights end-to-end – jumping between frontend, backend, and infrastructure. * Collaborate with the team on architecture design, best practices, and ensuring high-quality code across our stack. * Continuously improve the quality of services and the overall developer experience. * Engage frequently with our developer community to identify pain points and solve them. WHAT WE'RE LOOKING FOR * 7+ years of experience building, shipping and scaling high-quality software. * You ship fast and can solve any problem thrown at you end-to-end. * Strong proficiency with our stack or a variety of similar programming languages and ability + desire to quickly learn and pickup new tools. * Strong problem-solving abilities with an eye for developer experience. * Experience with cloud infrastructure and multi-cloud environments. * Excellent collaboration skills - comfortable working closely with a small, high-performing team. It's a startup so we all have to lean-in across the board to. * You care deeply about your craft - be it delightful animations, thoughtful edge-case handling, developer experience or performance optimizations. * (Bonus) You're an ex-founder/startup CTO, open source maintainer or indie hacker. * (Bonus) Experience working with payments, billing, or developer tools. WHAT WE OFFER * Meaningful ownership: Small team & large surface area. You’ll directly influence how the company and platform scale. * Product-driven culture: We build to empower the next generation of software companies - and operate with the same builder mindset internally. * Competitive compensation: Salary and equity aligned with the impact of the role. * Exceptional team: Work with highly talented team members distributed across Europe. * Remote-first environment: Work from anywhere in Europe, with a home office setup budget available. * Annual team offsites: As the team is spread across Europe, we gather in person at least once a year to collaborate, plan, and spend time. * Health Benefits: Comprehensive health coverage to support you and your family. * Parental leave: Paid parental leave aligned with the standards and regulations of your local jurisdiction. HOW WE HIRE Polar is a remote-first company, with team members across Europe, and our hiring process is fully remote via video calls and email. HIRING PROCESS 1. Application Review: We review your application and previous work. 2. Intro call: A short conversation with Birk (Founder and CEO) to learn more about you and give you a chance to learn more about Polar. 3. Take-home Assignment: A practical exercise designed to reflect the kind of problems you would work on in the role. 4. Assignment Review: We review your assignment and feedback together 5. Team Conversations: 2-3 video calls where you get the chance to meet future team members. 6. Offer 🎉 7. Reference Calls

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 Platform Engineer to architect and evolve the Polar platform - ensuring the system remains fast, resilient and operationally sound as we scale. Polar operates as a merchant of record, meaning our platform sits directly in the critical path of global payments, billing infrastructure and financial workflows. Reliability, uptime and correctness are essential - while still maintaining the ability to move quickly and ship product improvements. You’ll work across the platform and infrastructure layers that power Polar - from core infrastructure and observability to deployment safety, internal tooling and reliability engineering. In close partnership with the team, you’ll ensure the system scales to handle increasing traffic, architectural complexity and regulatory demands without compromising stability, performance or developer velocity. This role is ideal for someone who treats reliability as a product requirement and scalability as an architectural discipline, combining deep systems engineering experience with a passion for building reliable, scalable platforms and empowering engineering teams through strong abstractions and automation. While this role focuses primarily on the foundational layers of our platform, we value engineers who are comfortable moving across the stack when needed to ship quickly and maintain momentum. You’ll work with the team to: * Ensure Platform Reliability & Uptime: Design and evolve systems that maintain high availability, predictable performance and operational stability. Drive improvements in uptime, resilience and operational discipline as the system scales. * Engineer for Scale & Performance: Strengthen how our distributed services behave under load. Identify bottlenecks, optimize critical paths and design systems that scale with growing traffic and complexity. * Advance SRE & DevOps Practices: Embed reliability engineering practices across the platform - defining SLOs and SLIs, improving incident response, reducing operational toil and making production behavior measurable and actionable. * Evolve Cloud & Infrastructure Systems: Continuously evolve Polar’s infrastructure baseline and determine when the current stack needs to evolve. Improve infrastructure-as-code, environment management and operational safety mechanisms. * Strengthen Deployment & Operational Safety: Refine CI/CD systems, rollout strategies and rollback mechanisms to ensure changes are safe, observable, reversible and fast to deploy. * Improve Observability & Debuggability: Advance logging, metrics and tracing standards so engineers can quickly understand, debug and resolve issues in production. * Collaborate across Engineering, Risk & Legal: Work closely with product and infrastructure engineers, as well as risk and legal stakeholders, to translate evolving regulatory requirements into clear technical abstractions while maintaining long-term platform reliability and health. WHAT WE’RE LOOKING FOR Systems Thinking & Operating Mindset * Deep systems thinking: You anticipate failure modes, design for idempotency and consistency, and think carefully about how distributed systems behave in production. * Security- and compliance-aware engineering mindset: You build with auditability, principled access control and regulatory constraints as first-order design considerations. * End-to-end ownership: You are comfortable owning features from infrastructure and backend systems all the way to shipping functionality that powers the product. While this role focuses on platform layers, we value engineers willing to work across the stack when needed. * Strong product judgement: You know when to move fast while ensuring that correctness, auditability and long-term system integrity take precedence. * High-ownership collaboration: You thrive in small teams, collaborating closely across engineering to evolve the platform architecture and take shared responsibility for the long-term health of the system. 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 long-term data correctness, performance and reliability across large datasets. * Strong production debugging and observability instincts with an ability to trace complex issues across services and understand how to prevent them in the future. * Experience building or operating distributed systems with strong reliability and operational requirements. Experience * 5-8+ years of engineering experience, building and scaling customer-facing SaaS or fintech products in a high-growth environment. * Experience in payments and billing infrastructure - subscription lifecycles, transaction orchestration, refunds/disputes, payouts and financial state management. Nice-to-have: Open source contributions or side projects/apps to showcase. WHAT WE OFFER * Meaningful ownership: Small team & large surface area. You’ll directly influence how the company and platform scale. * Product-driven culture: We build to empower the next generation of software companies - and operate with the same builder mindset internally. * Competitive compensation: Salary and equity aligned with the impact of the role. * Exceptional team: Work with highly talented team members distributed across Europe. * Remote-first environment: Work from anywhere in Europe, with a home office setup budget available. * Annual team offsites: As the team is spread across Europe, we gather in person at least once a year to collaborate, plan, and spend time. * Health Benefits: Comprehensive health coverage to support you and your family. * Parental leave: Paid parental leave aligned with the standards and regulations of your local jurisdiction. HOW WE HIRE Polar is a remote-first company, with team members across Europe, and our hiring process is fully remote via video calls and email. HIRING PROCESS 1. Application Review: We review your application and previous work. 2. Intro call: A short conversation with Birk (Founder and CEO) to learn more about you and give you a chance to learn more about Polar. 3. Take-home Assignment: A practical exercise designed to reflect the kind of problems you would work on in the role. 4. Assignment Review: We review your assignment and feedback together 5. Team Conversations: 2-3 video calls where you get the chance to meet future team members. 6. Offer 🎉 7. Reference Calls