Payment Software Engineer Jobs in California (NOW HIRING)

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 250,000 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 2,300 of the brightest and most innovative people in tech across 27 offices around the globe. Valued at US$11 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.

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 Opportunity:

The Global Treasury and Payment Network (GTPN) team sits at the core of Airwallex’s payment infrastructure. As Airwallex’s very first product and still the largest revenue driver across the company, GTPN underpins many of our most critical customer experiences. We operate at the intersection of traditional and modern finance, expanding the reach of our global treasury and payment network, strengthening its capabilities and reliability, and delivering innovative payment products built on a robust financial foundation.

GTPN is a truly global, cross‑site engineering organization, with talented engineers in existing and emerging hubs such as Singapore and Shanghai. As we continue to scale worldwide, we’re looking for passionate Senior Software Engineers to join us. You’ll collaborate closely with product managers, designers, and engineers across regions to build and enhance products that not only meet but exceed our customers’ expectations.

As the senior engineer in the team, you will own the end-to-end development of solutions that redefine how we provide support and automation for both internal teams and external customers. You will shape the underlying architecture and APIs for advanced systems building cutting‑edge solutions that enable Airwallex to scale. Your contributions will directly influence innovation, set best practices, and establish the foundation for our expanding AI portfolio.

If you are passionate about building solutions that directly impact customers, thrive on solving tough technical challenges, and embrace a product‑focused mindset, we invite you to shape the future of Finance and AI with us.

• Have 5+ years of software engineering experience in Java/Spring Boot

• Excel at making the right level of abstraction—balancing flexibility and simplicity in system/component design

• Demonstrate clean communication across technical and non‑technical stakeholders

• Make pragmatic decisions on when to optimize for performance vs. velocity based on business impact

• Thrive in cross‑functional environments spanning Product, Design, Compliance, and Sales

• Design for scale, maintainability, and production excellence

Bonus if you have

• Fintech, payments, or regulated industry experience

• High‑scale performance tuning (100k+ QPS, large user bases, strict latency SLAs)

• Multi‑tenant SaaS or platform architecture background

• Proficiency with PostgreSQL, Redis, Kafka, or cloud platforms (AWS/GCP/Azure)

• Experience with OAuth2.0, API design, or developer documentation

• Cross‑region deployment or data residency compliance experience

• Solutions engineering or customer‑facing technical experience

Why Join Us

• Grow Beyond Engineering: You'll develop expertise that extends beyond technical skills: understanding customer business models, navigating regulatory landscapes, influencing enterprise sales. This is career growth that prepares you for technical leadership, product roles, or even founding your own company.

• Join a World‑Class Team: Work with exceptional engineers, product thinkers, and designers across the globe. At Airwallex, you'll be challenged, supported, and surrounded by people who are building something meaningful together.

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 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.