Senior Backend Engineer, Spend Team (Cards)

Airwallex; Singapore; On-site; SGD 120,000 - 180,000; Full time

Job summary

Airwallex is seeking a Senior Engineer for the Cards team in Singapore. You will design and build scalable backend systems powering card issuance and expense management, collaborating with cross-functional teams and mentoring engineers to drive secure, reliable features.

The role is based in Singapore and focuses on delivering robust backend services, architecture ownership, and high-quality code with strong emphasis on observability and API design.

Qualifications

• Bachelor's degree in CS or related field.
• 5+ years of professional software engineering experience.
• Experience designing and building backend systems and APIs in production.
• Strong CS fundamentals: algorithms and distributed systems.
• Proficiency in one backend language (Java, Kotlin, Go, Python).
• Experience with cloud infra (AWS, GCP) and Kubernetes.
• Focus on performance, reliability, and code quality.

Responsibilities

• Design scalable backend services for the Cards product.
• Contribute to architecture and long-term technical vision.
• Own end-to-end delivery from design to production.
• Write high-quality, testable code with reliability.
• Uphold engineering best practices, observability, API design.
• Collaborate with product, infra, design.
• Mentor other engineers.

Skills

5+ years experience

Backend design

REST API design

Cloud infrastructure

Kubernetes

Performance focus

Testable code

Mentoring

Education

Bachelor’s degree in CS

Tools

Spring Boot

AWS

GCP

Kubernetes

Docker

Job description

About Airwallex

Airwallex is the AI-native financial operating system for a real-time, intelligent economy. More than 675,000 businesses, including McLaren Racing, Qantas, SHEIN, and TikTok, use us, directly or through our platform partners, to run their financial operations or build and monetize financial products of their own.

We started in Melbourne in 2015 to build the infrastructure global commerce runs on. We're the regulated backbone behind global payments: not by accident, but by design. A decade plus, 85+ licenses, and a financial infrastructure spanning North America, Europe, the Middle East, and Asia-Pacific.

We're co-headquartered in San Francisco and Singapore, with more than 2,700 people across 27 offices. We hire builders with founder-level energy, people who move fast with good judgment, dig in with real curiosity, and make calls from first principles rather than waiting to be told what to do. Read our operating principles to see it in full.

About the team

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 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 do

As 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.

Responsibilities

• Design 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 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 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 qualifications

• Familiarity with observability and monitoring tools (e.g., Grafana, Prometheus, Splunk).

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.