Senior Java Full-Stack Engineer – Payments & APIs

TECH AALTO PTE. LTD.; Singapore; On-site; SGD 120,000 - 180,000; Full time

Job summary

Tech Aalto Pte. Ltd. in Singapore seeks a Senior Java Full Stack Developer with 8+ years of software experience in payments. You will design and build secure, scalable payment applications across backend and frontend, and guide engineering decisions.

You will lead full-stack development, implement REST APIs, integrate payment gateways, ensure security, and mentor others while collaborating with product, QA and design teams.

Qualifications

• 8+ years of professional software development experience, including full-stack development.
• Strong experience with Java, Spring Boot, and related backend technologies.
• Hands-on frontend experience with JavaScript or TypeScript and Angular or React.
• Experience designing and consuming REST APIs and building microservices.
• Significant experience in the payments domain, including payment processing/integration.
• Knowledge of payment workflows such as authorization, capture, refunds, settlement, and reconciliation.
• Experience with relational databases (PostgreSQL, MySQL, Oracle).
• Familiarity with messaging platforms (Kafka, RabbitMQ).
• Experience with Git, automated testing, and build tools.
• Strong understanding of application security, authentication, authorization, and data protection.

Responsibilities

• Lead design, development, testing, and maintenance of full-stack applications using Java and modern frontend technologies.
• Build scalable backend services and REST APIs for payment processing and related workflows.
• Develop responsive user interfaces and integrate them with backend services.
• Design and support payment flows: authorization, capture, refunds, settlement, reconciliation, status tracking.
• Integrate with payment gateways, processors, banks, and other third-party services.
• Apply secure coding practices and support payment-security compliance.
• Identify and resolve production issues; improve performance, reliability, and scalability.
• Write and review unit, integration, and automated tests.
• Participate in architecture and design discussions, code reviews, and planning.
• Mentor developers and collaborate with product, QA, design, and other teams.

Skills

Java

Spring Boot

Frontend (JS/TS)

Angular/React

REST APIs

Payments domain

Databases

Messaging (Kafka/RabbitMQ)

Git & CI/CD

Security

Tools

Docker

Kubernetes

CI/CD

Job description

Tech Aalto Pte. Ltd. in Singapore seeks a Senior Java Full Stack Developer with 8+ years of software experience in payments. You will design and build secure, scalable payment applications across backend and frontend, and guide engineering decisions.

You will lead full-stack development, implement REST APIs, integrate payment gateways, ensure security, and mentor others while collaborating with product, QA and design teams.