Senior Backend Engineer, Expenses

About Airwallex
Airwallex 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 Value
We 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.
The 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 Expenses team builds innovative solutions that simplify the entire expense management process for our customers. From real-time expense tracking and automated receipt capture to seamless approvals and integrations, we deliver tools that give businesses greater control and efficiency over global spending.
What you'll do
As a Senior Backend Engineer, you'll take full ownership of critical backend systems that power our expenses product, driving the technical direction, architecture, and long term scalability of our platform. You'll design, build, and evolve high performance, secure, and maintainable systems.
This role is based in San Francisco.
Responsibilities:

• Lead the design, architecture, and implementation of backend services, ensuring they are robust, scalable, and secure.
• Write clean, maintainable, and testable code, setting the standard for engineering excellence across the team.
• Drive technical discussions, design reviews, and code reviews, fostering a culture of high quality engineering.
• Design and maintain high-performance REST APIs, adhering to best practices in API design and security.
• Proactively address system reliability, scalability, and observability, implementing the right monitoring and alerting strategies.
• Collaborate closely with product managers, designers, and other engineers to deliver high impact solutions.
• Mentor and coach other engineers, guiding them on technical and architectural decisions.
• Contribute to technical strategy and long term engineering roadmap.

Who you are
We're looking for people who meet the minimum qualifications for this role. The preferred qualifications are great to have, but are not mandatory.
Minimum qualifications

• Bachelor's degree in Computer Science, Software Engineering, or related field.
• 6+ years of professional backend software development experience.
• Strong foundation in computer science fundamentals
• Proven experience building and scaling RESTful APIs and working with modern backend technologies.
• Proficiency with at least one modern programming language (Java, Kotlin, Go, Python, etc.).
• Experience with cloud platforms (AWS, GCP, or Azure).
• Strong understanding of CI/CD, automated testing, and code quality practices.

Preferred qualifications

• Experience with Spring Boot or another modern backend framework.
• Exposure to cloud infrastructure tools such as Kubernetes or similar.
• amiliarity with observability tools (e.g., Grafana, Prometheus, or Splunk).
• Interest or experience in the financial domain.

Applicant Safety Policy: Fraud and Third-Party Recruiters
To 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 opportunity
Airwallex 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.