Senior Software Engineer, Backend

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 150,000 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 1,700 of the brightest and most innovative people in tech across 26 offices around the globe. Valued at US$6.2 billion and backed by world-leading investors including Visa, Airtree, Blackbird, Sequoia, DST Global, Greenoaks, Salesforce Ventures, Lone Pine, and Square Peg, 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. Airwallex is a rapidly growing fintech unicorn, founded in 2015 and now flourishing at the Series E financing stage. With a global footprint across Asia-Pacific, Europe, North America, and APAC, we specialize in providing diverse financial payment solutions for B2B merchants, empowering businesses to operate seamlessly anywhere, anytime. Core Responsibilities As a Senior Software Engineer , you will be responsible for designing and building the core services that power our platform. You will tackle complex technical challenges, ensuring our systems remain highly available, scalable, and efficient as we continue to grow globally. Architecting Scalable Systems: Design and implement robust, high-performance backend services capable of handling high-volume traffic and complex data workflows. Optimizing Distributed Infrastructure: Build and maintain reliable internal and external-facing systems, focusing on low latency and high availability. Enhancing Data Retrieval: Develop and optimize search and data platforms to ensure fast and accurate information retrieval across distributed datasets. Driving Engineering Excellence: Lead technical initiatives, perform deep-dive code reviews, and mentor junior engineers to maintain high standards of code quality and system design. Cross-Functional Collaboration: Partner with Product, DevOps, and Security teams to translate business requirements into scalable technical solutions. What You’ll Do Solve High-Scale Challenges: Address intricate, organization-wide problems by leveraging modern technologies in distributed systems, reactive programming, and workflow orchestration. Build Mission-Critical Infrastructure: Develop shared libraries and frameworks that eliminate technical bottlenecks and accelerate the pace of innovation across the entire engineering organization. Technical Strategy: Conduct evaluations of emerging technologies and guide long-term architectural decisions to ensure global resilience and efficiency. Minimum Qualifications Technical Expert: You have strong proficiency in backend programming languages such as Java, Go, Rust, or Python and their associated ecosystems. Distributed Systems Specialist: You have a deep understanding of microservices architecture, including service discovery, load balancing, and inter-service communication. Database & Storage Expert: You possess hands-on experience with relational and non-relational databases (e.g., PostgreSQL, Redis, Elasticsearch ) and understand data consistency and performance tuning at scale. Cloud & Infrastructure Literate: You are comfortable working with cloud providers (AWS, GCP, or Azure) and container orchestration tools. API Specialist: You have extensive experience in API design and lifecycle management, with a firm grasp of security protocols (OAuth, JWT, mTLS). Clear Communicator: You can articulate complex technical concepts to both technical and non-technical stakeholders in a multicultural environment. Good to have Performance Engineering: Experience with advanced profiling (e.g., flame graphs) and system-level optimization. Observability & Reliability: Familiarity with monitoring, tracing, and logging tools (Prometheus, Jaeger, ELK) to maintain system health. Open Source Contributor: You actively follow or contribute to the open-source community and enjoy bringing cutting-edge industry trends into your work. Familiarity with Kubernetes and Docker.