Senior Java Full-Stack Engineer - Payments & APIs

Tech Aalto Pte ltd; Singapore; On-site; SGD 150,000 - 190,000; Full time

Job summary

Tech Aalto Pte Ltd is seeking a Senior Java Full Stack Developer with 8+ years of software development experience, focused on payments. You will design and build secure, scalable payment applications across backend services and frontend interfaces, guiding technical decisions and engineering practices.

You will lead the design, development, testing, and maintenance of full-stack applications, build scalable backend services and REST APIs for payment processing, and develop responsive UIs

Qualifications

• 8+ years of professional software development experience.
• 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 or payment-system integrations.
• Knowledge of payment workflows such as authorization, capture, refunds, settlement, and reconciliation.
• Experience with relational databases such as PostgreSQL, MySQL, or Oracle.
• Familiarity with messaging platforms such as Kafka or RabbitMQ.
• Experience with Git, automated testing, and build tools.
• Strong understanding of application security, authentication, authorization, and data protection.

Responsibilities

• Lead the 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, transaction management, and related workflows.
• Develop responsive user interfaces and integrate them with backend services.
• Design and support payment flows, including authorization, capture, refunds, settlement, reconciliation, and transaction-status tracking.
• Integrate with payment gateways, processors, banks, and other third-party financial services.
• Apply secure coding practices and support compliance with relevant payment-security requirements.
• Identify and resolve production issues; improve application performance, reliability, and scalability.
• Write and review unit, integration, and automated tests.
• Participate in architecture and design discussions, code reviews, and technical planning.
• Mentor developers and collaborate with product, QA, design, and other engineering teams.

Skills

Java

Spring Boot

JavaScript/TypeScript

Angular/React

REST APIs

Microservices

Payments domain

PostgreSQL/MySQL/Oracle

Kafka/RabbitMQ

Git/CI tools

Security/Auth/Data protection

Tools

Docker

Kubernetes

CI/CD pipelines

Job description

Tech Aalto Pte Ltd is seeking a Senior Java Full Stack Developer with 8+ years of software development experience, focused on payments. You will design and build secure, scalable payment applications across backend services and frontend interfaces, guiding technical decisions and engineering practices.

You will lead the design, development, testing, and maintenance of full-stack applications, build scalable backend services and REST APIs for payment processing, and develop responsive UIs