Senior Software Engineer Backend, Billing

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 2,300 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 ouroperating principles to see it in full.

How you'll make impact

Airwallex’s Billing team is building the next generation of billing infrastructure for Airwallex and the businesses that use our platform. You’ll help shape the architecture and deliver reliable backend systems that support complex financial workflows.

• Lead the planning, design, and implementation of backend systems for Airwallex’s billing platform.

• Partner with Product and business teams to understand customer and business needs, shape technical direction, and deliver core functionality.

• Build reliable components within a microservices architecture, including systems that support flexible pricing, invoicing, and quote-to-cash workflows.

• Own the architecture and development of complex, distributed systems with high concurrency, high availability, and strong financial accuracy.

• Introduce practical technologies and engineering approaches that improve how the team builds, operates, and scales billing products.

• Raise the bar on engineering quality through clear design practices, coding standards, and constructive technical collaboration.

You'll work from our Singapore office

What we're looking for

Essentials

• 6+ years of core Java development experience and 5+ years building internet applications, large-scale financial systems, or e-commerce platforms. 1+ year of experience developing payment platforms.

• A bachelor’s degree in Computer Science or a related field.

• Strong command of Java 8, including multithreading, high concurrency, I/O or NIO, and network communication.

• Experience with common design patterns and the design and development of large-scale distributed, high-concurrency, high-load, and highly available systems.

• Experience with server-side technologies and with optimising service response and data queries to maintain service quality.

• A track record of solving complex engineering problems in production environments.

• The ability to work closely with Product and business teams, translate business needs into technical solutions, and make sound architectural decisions.

Preferred

• Experience with international clearing and settlement or foreign exchange transactions.

• Fluent English.

You'll thrive here if

• You're comfortable owning the roadmap yourself.

• You own the outcome and you don't wait for permission to fix what's broken.

• You're comfortable with ambiguity. Give you a problem, not a prescription, and you'll run with it.

• You hold yourself to a high standard even when no one is watching. Quality and accountability aren't external expectations, they're internal ones.

• You value in-person collaboration and are happy being in the office five days a week.

• You say what you mean. You're direct, but you lead with respect.

• You know when to align and when to just decide. Collaboration isn't a way to avoid accountability.

• You simplify complexity rather than hiding behind it.

Learn more about your team

The Billing team at Airwallex builds a single platform that charges for everything: how we bill our customers, and how our customers bill theirs. We own the quote-to-cash engine behind Airwallex's fastest-growing revenue stream, from usage-based billing and pricing to the checkout experience that collects across 130+ currencies and 160+ payment methods. The hard part: one system serves two masters, Airwallex's own books and the revenue of every business that bills through us, so every number has to reconcile to the cent, in real time, under audit scrutiny. You'll thrive here if correctness is non-negotiable and you think like a product owner as much as an engineer. If you want billing to be the growth engine of the AI economy, this is where it's built.

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.