(Senior) Software Engineer (Java/Golang), Zalopay

The Operation Platform team is responsible for centralizing and scaling all operational aspects of Zalopay, one of Vietnam’s leading financial platforms. Our mission is to build a unified, reliable, and extensible operation ecosystem that empowers operations teams to efficiently support millions of users, merchants, and partners.

Within this platform, the Reconciliation Core domain ensures that financial data from banks, merchants, partners, and internal systems is complete, accurate, and explainable. We build reconciliation engines, data pipelines, reporting capabilities, and operational tools that help Operations, Finance, Accounting, and Customer Service identify discrepancies, investigate issues, and protect financial integrity at scale.

We design systems at the intersection of technology, finance, and operations, where correctness, traceability, scalability, and timely processing are equally critical. Our systems process millions of financial transactions and integrate data from APIs, files, message queues, and distributed data platforms.

We are looking for a Software Engineer / Senior Software Engineer (Java/Golang) who enjoys solving complex data and distributed-system problems. Depending on your experience, you will own features end to end or lead the design and delivery of larger technical solutions within the Reconciliation Core domain.

Responsibilities

You will:

• Design, build, and maintain backend systems for reconciliation and financial data processing, including:

• Reconciliation engines for banks, merchants, partners, and internal systems

• Data ingestion pipelines using APIs, SFTP, files, and message queues

• Discrepancy detection, investigation, adjustment, and resolution workflows

• Operational dashboards, reports, and tools for Operations, Finance, Accounting, and Customer Service

• Build and evolve data-intensive services that process millions of transactions reliably and efficiently.

• Ensure data correctness, idempotency, auditability, consistency, and traceability across distributed reconciliation workflows.

• Design clear data models, APIs, and reusable components that support multiple reconciliation use cases.

• Work with multiple storage and data systems, such as:

  • Relational databases such as PostgreSQL or MySQL for transactional data

  • NoSQL databases such as MongoDB for appropriate use cases

• Redis for caching, coordination, and high-performance access

• Kafka or RabbitMQ for event-driven processing

• Develop and optimize batch, near-real-time, and file-based workflows for high-throughput financial data.

• Implement comprehensive automated testing, monitoring, alerting, and operational controls to maintain production reliability.

• Improve system observability and build traceable investigation flows for discrepancies and production incidents.

• Collaborate closely with Product, Business Operations, Finance, Accounting, Customer Service, and other Engineering teams to deliver end-to-end solutions.

• Participate in on-call rotation, troubleshoot complex production issues, and drive them through resolution.

• Contribute to architectural decisions, technical standards, code quality, and engineering best practices; senior candidates are expected to lead solution design and mentor other engineers.

You may be a good fit for this role if you:

• Hold a Bachelor’s or Master’s degree in Computer Science, Software Engineering, or a related field.

• Have at least 2 years of experience in backend software development; senior-level candidates should demonstrate strong ownership of production systems and technical design.

• Have strong proficiency in Java 17+ with Spring Boot and Golang, and are willing to work with both languages when needed.

• Have solid experience in backend system design, including API design, data modeling, service decomposition, and microservices.

• Have strong knowledge of relational databases and SQL, including transactions, indexing, query optimization, and performance tuning.

• Have hands-on experience with NoSQL databases such as MongoDB.

• Have experience with message queues or event-streaming platforms such as Kafka or RabbitMQ.

• Understand distributed-system concepts such as idempotency, concurrency control, eventual consistency, retry strategies, and failure handling.

• Are comfortable working with large datasets, batch jobs, and data exchanges through APIs, files, or SFTP.

• Have experience building, operating, and troubleshooting production systems at scale.

• Demonstrate strong problem-solving skills, end-to-end ownership, and attention to detail when working with financial data.

• Write clean, maintainable, and well-tested code.

Nice to have:

• Experience in FinTech, payments, banking, e-commerce, reconciliation, clearing, or settlement systems.

• Understanding of accounting principles, double-entry bookkeeping, and financial workflows.

• Experience integrating data from multiple sources and formats, including bank APIs and SFTP.

• Hands-on experience with Apache Airflow for ETL/ELT workflow orchestration.

• Hands-on experience with Apache Spark or similar technologies for large-scale batch or stream processing.

• Experience with reporting, analytics, investigation tools, or operational dashboards.

• Experience running systems in Kubernetes or cloud-native environments.

• Ability to work closely with non-technical stakeholders and translate financial or operational workflows into reliable technical solutions.