– Java Developer (4–6 Years)

Position

Java Developer – Payment Aggregation / Merchant Payments

Experience

4–6 years

Job Location Chennai

Role Overview

We are looking for an experienced Java Developer with 4–6 years of hands-on experience in Payment Aggregation (PA), Payment Gateway (PG), and merchant payment systems. The candidate should have strong knowledge of online and offline merchant transaction flows, including QR payments, Soundbox, UPI, POS and payment gateway integrations.

The role involves designing, developing, integrating, and supporting scalable payment services and APIs while working closely with product, business, operations, security,

and external payment partners.

Key Responsibilities

- Design, develop, and maintain backend applications using Java and Spring Boot.
- Develop and integrate REST APIs for Payment Aggregator (PA) and Payment

Gateway (PG) platforms.
- Understand and implement end-to-end online and offline merchant payment flows.
- Work on merchant payment journeys including:

o Online checkout/payment gateway o UPI payments o QR-based payments o Static and Dynamic QR o POS transactions o Soundbox integration o Merchant onboarding and transaction processing o Payment status, callback and webhook handling o Refunds, reversals and reconciliation
- Integrate with banks, UPI providers, payment processors, switches and other third-party payment service providers.
- Develop transaction processing APIs with appropriate validation, error handling,

logging and security controls.
- Work on transaction lifecycle management, including initiation, authorization,

success/failure, timeout, reversal, refund and settlement.
- Implement secure and scalable APIs for high-volume payment transactions.
- Troubleshoot production issues, transaction failures and integration issues with external vendors.
- Analyse transaction logs and API responses to identify root causes and provide fixes.
- Participate in code reviews,



technical discussions and solution design.
- Work closely with QA teams for SIT/UAT and production release activities.
- Support performance testing and production monitoring of payment services.
- Ensure development follows security, coding and compliance standards applicable to payment systems.

Required Technical Skills

- Strong hands-on experience in Core Java.
- Strong knowledge of Java 8/11/17+.
- Good experience with Spring Boot, Spring MVC and REST APIs.
- Experience in microservices architecture.
- Robust understanding of REST API design and third-party API integration.
- Good knowledge of SQL and relational databases, preferably MySQL/Oracle.
- Experience with JSON, XML, HTTP/HTTPS and API authentication mechanisms.
- Knowledge of asynchronous processing, messaging and event-driven architecture is an advantage.
- Experience with Git and CI/CD processes.
- Good understanding of application logging, monitoring and troubleshooting.
- Knowledge of cloud platforms such as AWS is preferred.

Payment Domain Skills – Mandatory

Candidates should have practical experience in one or more of the following:

- Payment Aggregator (PA)
- Payment Gateway (PG)
- Merchant Acquiring
- UPI
- Online payment processing
- Offline merchant payment processing
- QR payments – Static/Dynamic QR
- Soundbox
- POS / QR merchant transactions
- Payment status and callback/webhook processing
- Refund and reversal processing
- Settlement and reconciliation
- Merchant onboarding
- Transaction monitoring and failure handling

Preferred Knowledge

- UPI transaction lifecycle and payment flows.
- Merchant acquiring ecosystem.
- QR and Soundbox transaction architecture.
- Payment switch and processor integrations.
- Idempotency and duplicate transaction handling.
- Transaction reconciliation and settlement processes.
- Fraud Risk Management / transaction risk checks.
- PCI-DSS and payment security concepts.
- Encryption, masking and secure handling of payment/customer data.

📌 Java Developer (Chennai)
🏢 GreatHR Solutions
📍 Chennai