Senior Backend Engineer, Spend Team (Cards) About AirwallexAirwallex is the only unified payments and financial platform for global businesses. Powered by our unique combination of proprietary infrastructure and software, we empower over 200,000 businesses worldwide – including Brex, Rippling, Navan, Qantas, SHEIN and many more – with fully integrated solutions to manage everything from business accounts, payments, spend management and treasury, to embedded finance at a global scale.Proudly founded in Melbourne, we have a team of over 2,000 of the brightest and most innovative people in tech across 26 offices around the globe. Valued at US$8 billion and backed by world-leading investors including T. Rowe Price, Visa, Mastercard, Robinhood Ventures, Sequoia, Salesforce Ventures, DST Global, and Lone Pine Capital, Airwallex is leading the charge in building the global payments and financial platform of the future. If you’re ready to do the most ambitious work of your career, join us.Attributes We ValueWe hire successful builders with founder-like energy who want real impact, accelerated learning, and true ownership. You bring strong role-related expertise and sharp thinking, and you’re motivated by our mission and operating principles. You move fast with good judgment, dig deep with curiosity, and make decisions from first principles, balancing speed and rigor.You're humble and collaborative; turn zero‑to‑one ideas into real products, and you “get stuff done” end-to-end. You use AI to work smarter and solve problems faster. Here, you’ll tackle complex, high‑visibility problems with exceptional teammates and grow your career as we build the future of global banking. If that sounds like you, let’s build what’s next.About the teamThe Engineering team at Airwallex is a diverse group of innovators, builders, and problem solvers, driven by a mission to empower businesses to operate anywhere, anytime. We thrive in a collaborative and fast-paced environment, where we're constantly pushing the boundaries of what's possible in the financial technology space. As a team, we value technical craftsmanship, continuous learning, and a strong sense of ownership, working together to build scalable, reliable, and secure products that empower businesses of all sizes to grow without borders.The Cards team at Airwallex builds and maintains distributed systems that enable businesses to issue debit cards and manage expenses at scale. The team addresses complex requirements around compliance, security, and the evolving needs of global users—supporting millions of seamless card transactions and ensuring robust, reliable expense management solutions for companies worldwide.What you'll doAs a Senior Engineer on the Cards team, you will design and build scalable backend systems that power our card issuance and expense management products. You will collaborate with cross-functional teams to deliver reliable, secure features while mentoring engineers and influencing the technical direction of the platform.This role is based in Singapore.ResponsibilitiesDesign and implement scalable, secure backend services that power the Cards product.Contribute to the architecture and long-term technical vision of our backend systems.Own end-to-end delivery of new features and improvements—from design to production.Write high-quality, testable code with attention to reliability and maintainability.Promote and uphold engineering best practices, including observability and API design.Collaborate with cross-functional teams including product, infrastructure, and design.Provide technical mentorship and support the growth of other engineers on the team.Who you areWe're looking for people who meet the minimum qualifications for this role. The preferred qualifications are great to have, but are not mandatory.Minimum qualificationsBachelor’s degree in Computer Science, Software Engineering, or a related field.5+ years of professional software engineering experience.Hands-on experience designing and building backend systems and APIs in production.Strong computer science fundamentals, including algorithms, data structures, and distributed systems.Proficient in at least one backend language (e.g., Java, Kotlin, Go, Python).Solid understanding of REST API design and backend frameworks (e.g., Spring Boot).Experience working with cloud infrastructure (e.g., AWS, GCP) and container orchestration (e.g., Kubernetes).Strong focus on performance, reliability, and code quality.Preferred qualificationsFamiliarity with observability and monitoring tools (e.g., Grafana, Prometheus, Splunk).Applicant Safety Policy: Fraud and Third-Party RecruitersTo protect you from recruitment scams, please be aware that Airwallex will not ask for bank details, sensitive ID numbers (i.e. passport), or any form of payment during the application or interview process. All official communication will come from an @airwallex.com email address. Please apply only through careers.airwallex.com or our official LinkedIn page.Airwallex does not accept unsolicited resumes from search firms/recruiters. Airwallex will not pay any fees to search firms/recruiters if a candidate is submitted by a search firm/recruiter unless an agreement has been entered into with respect to specific open position(s). Search firms/recruiters submitting resumes to Airwallex on an unsolicited basis shall be deemed to accept this condition, regardless of any other provision to the contrary.Equal opportunityAirwallex is proud to be an equal opportunity employer. We value diversity and anyone seeking employment at Airwallex is considered based on merit, qualifications, competence and talent. We don’t regard color, religion, race, national origin, sexual orientation, ancestry, citizenship, sex, marital or family status, disability, gender, or any other legally protected status when making our hiring decisions. If you have a disability or special need that requires accommodation, please let us know.