Senior Software Engineer, Transaction Risk

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.
About the team
Airwallex Risk Platform Team is responsible for protecting all Airwallex products across the lifecycle, including GTPN, PA, Issuing, Onboarding, and Account Takeover. The risk landscape evolves rapidly and fraud techniques are becoming increasingly sophisticated. We build scalable, reliable, and intelligent risk capabilities to stay ahead-helping Airwallex remain a trusted global partner for businesses.
Our team is distributed across Shanghai and Singapore, working closely with global product, engineering, data, and operations teams, as well as external partners and customers, to deliver a holistic risk management approach.
This role is based in Singapore.
What you'll do
Our mission is to keep Airwallex's products and services safe and secure. We continuously improve risk strategies and systems using modern technologies, including graph, machine learning, and LLMs/Gen AI, to detect and prevent fraud and abuse at scale.
Responsibilities:

• Design, develop, and operate core transaction risk services and infrastructure using Kotlin/Java, supporting payment products and transaction systems.
• Own end-to-end delivery of key components and services on Airwallex's microservice framework: design, implementation, testing, deployment, and observability.
• Build high-concurrency, highly available distributed services, optimizing latency, throughput, and reliability for production workloads.
• Collaborate with senior engineers and cross-functional partners to define technical solutions, APIs, and service boundaries; drive architectural improvements.
• Explore and evaluate new technologies (e.g., graph/streaming/ML/LLM related) and propose pragmatic upgrades aligned with business risk needs.
• Mentor engineers through code reviews, design discussions, and engineering best practices, improving team quality and delivery efficiency.
• Participate in on-call/incident response when needed, driving root-cause analysis and long-term remediation.

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

• 5+ years experience in Java/Kotlin backend development, with proven delivery in internet-scale applications, large financial systems, or e-commerce platforms.
• 3+ years experience building systems for risk platforms and/or payment platforms.
• Bachelor's degree in Computer Science or related fields (or equivalent practical experience).
• Strong knowledge of Java ecosystem, including concurrency/multithreading, high-throughput IO (NIO), and network communication fundamentals.
• Solid foundation in distributed systems design: high concurrency, high load, high availability, resilience, and scalability.
• Strong engineering practices: performance tuning, service stability, data/query optimization, and production troubleshooting.
• Experience with Spring / Spring Boot and designing RESTful APIs.
• Familiarity with build tools such as Gradle/Maven.
• Familiarity with common data formats such as JSON (XML is a plus, not a must).

Preferred Qualifications (Nice to Have)

• Strong domain knowledge in risk management, fraud detection, and fintech payment risk strategies.
• Experience with graph databases and graph-based pattern/anomaly detection.
• Experience applying machine learning for predictive risk analytics (model integration, feature engineering collaboration, etc.).
• Experience with real-time streaming and event-driven architectures (e.g., Kafka, Flink) for low-latency detection and response.
• Experience with large-scale analytics and storage technologies (e.g., ClickHouse, Spark, NoSQL) for risk analysis and investigations.
• Incident response experience, including mitigation planning and post-incident improvement.
• Strong communication and collaboration skills in a cross-regional, cross-functional environment.
• Familiarity with LLM evaluation and safety practices (offline/online evals, red teaming, prompt injection defenses, PII handling, and guardrails) for enterprise use cases.

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.