Senior Frontend Software Engineer

About the Company At Avaron, you get the security of permanent employment combined with the variety of working at different customers. We place specialists across everything from tech, IT and industry to project management and business support – and whatever the assignment, you have a consultant manager who is there for you and your development. About the Role You will help shape checkout and payment experiences in a complex product environment where performance, reliability, accessibility and security matter in every release. The role is centered on modern frontend engineering, with real influence over architecture, state management, API integration and the way features move from design to production. You will work closely with backend, SRE, security and product teams to build scalable solutions for large enterprise applications, solve issues early across environments, and strengthen engineering practices across the codebase. This is a great role if you enjoy hands-on development while also influencing technical direction in a domain where small improvements can make a real difference. Job DescriptionYou will own end-to-end delivery of complex frontend features using TypeScript and React, from design through production. You will design scalable, maintainable frontend architecture with focus on modularization, code splitting and performance. You will drive state management strategy using approaches such as Redux, Zustand or React Query to support predictable data flow and strong application performance. You will build and integrate with APIs and BFF layers, and contribute to Node.js services when needed. You will turn product and design requirements into high-quality, accessible UI with semantic HTML, responsive CSS and WCAG-aware implementation. You will optimize rendering, bundle size, network usage and caching to improve the user experience. You will set coding standards, review code, mentor other engineers and help raise the overall engineering bar. You will troubleshoot and resolve complex issues using structured debugging, logging and observability tools. You will embed secure coding practices into development, including input validation, authentication flows and data protection, with extra attention to payment-related flows. You will contribute to CI/CD, testing strategy across unit, integration and end-to-end testing, and iterative delivery in an Agile setup. RequirementsStrong experience in the payments domain, particularly checkout flows Deep expertise in Next.js, React and TypeScript Exposure to backend development Strong troubleshooting and debugging capabilities Ability to work across the full feature lifecycle, from design discussions to production delivery Nice to haveExperience working with complex enterprise-scale applications Full-stack exposure with Node.js, API design and BFF patterns Knowledge of PCI considerations and transaction handling Familiarity with cloud platforms and edge/CDN strategies Experience with design systems and component libraries at scale What We OfferPermanent employment at Avaron AB Occupational pension Wellness allowance of SEK 5,000 per year Application Selections are made on an ongoing basis – apply as soon as you can.