Role Overview

We are looking for a Java Developer with 4 to 6 years of experience and strong hands-on exposure to Payment Aggregation, Payment Gateway, Merchant Acquiring, UPI, QR, POS, and merchant payment systems.

The candidate will be responsible for developing and integrating scalable payment services and REST APIs, implementing transaction processing flows, troubleshooting payment issues, and integrating with banks, payment processors, UPI providers, switches, and third-party payment service providers.

Key Responsibilities

- Develop and maintain backend applications using Core Java, Spring Boot, Spring MVC, and REST APIs.
- Design and integrate APIs for Payment Aggregator (PA) and Payment Gateway (PG) platforms.
- Implement online and offline merchant payment flows.
- Work with UPI, Static/Dynamic QR, POS, Soundbox, and merchant payment transactions.
- Develop transaction lifecycle capabilities covering payment initiation, authorization, success/failure, timeout, reversal, refund, settlement, and reconciliation.
- Integrate with banks, UPI providers, payment processors, switches, and external payment service providers.
- Handle callbacks, webhooks, payment status updates, and transaction failures.
- Implement transaction validation, error handling, logging, security, and duplicate/idempotent transaction handling.
- Troubleshoot production issues using transaction logs, API responses, and monitoring tools.
- Participate in code reviews, technical discussions, SIT/UAT, performance testing, and production releases.




- Follow secure coding and applicable payment security/compliance practices.

Mandatory Technical Skills

- 4 to 6 years of Java development experience
- Robust Core Java / Java 8/11/17+
- Spring Boot, Spring MVC, REST APIs
- Microservices architecture
- REST API and third-party API integration
- SQL with MySQL/Oracle or similar relational databases
- JSON, XML, HTTP/HTTPS and API authentication
- Git and CI/CD
- Application logging, monitoring, and troubleshooting

Mandatory Payment Domain Experience Candidates must have practical experience in one or more of:
- Payment Aggregator / Payment Gateway
- Merchant Acquiring
- UPI payments
- Online/offline merchant payments
- Static/Dynamic QR
- POS transactions
- Soundbox
- Payment callbacks/webhooks
- Refunds and reversals
- Settlement and reconciliation
- Merchant onboarding
- Transaction monitoring and failure handling

Preferred: AWS, asynchronous processing, messaging/event-driven architecture, payment switches, idempotency, fraud/risk checks, PCI-DSS, encryption and secure payment-data handling. Contract & Work Location

- Contract Duration: 6 months
- Employment Type: Contract-to-Hire
- Extension/Conversion: The contract may be extended or converted to a permanent position based on project requirements and performance.
- Work Location: Chennai, Tamil Nadu
- Work Mode: Onsite
- Candidates must be willing to work onsite in Chennai throughout the contract period.
- Candidates should be open to conversion to a permanent/full-time role after the contract period.

📌 Java Developer Payment Aggregation / Merchant Payments (Chennai)
🏢 ThreatXIntel
📍 Chennai