Company Description

ThreatXIntel is a growing Cybersecurity, IT Staffing, and Consulting company delivering end-to-end technology and security solutions.

We are hiring for our corporate client. ThreatXIntel is the official hiring partner for this requirement.

About the Role

We are looking for a Java Developer with 4–6 years of experience in Payment Aggregation, Payment Gateway, Merchant Acquiring, UPI, or merchant payment systems.

The ideal candidate should have strong hands-on experience with Java, Spring Boot, REST APIs, microservices, and practical exposure to online/offline merchant payment flows, UPI, QR, POS, Soundbox, refunds, reversals, callbacks, settlement, and reconciliation.

Key Responsibilities

- Design, develop, and maintain backend payment applications using Java and Spring Boot.
- Develop and integrate REST APIs for Payment Aggregator and Payment Gateway platforms.
- Implement end-to-end merchant payment transaction flows.
- Work with UPI, Static/Agile QR, POS, Soundbox, online checkout and payment gateway integrations.
- Develop payment status, callback and webhook processing.
- Implement refund, reversal, settlement and reconciliation workflows.
- Integrate with banks, UPI providers, payment processors, switches and third-party payment partners.
- Build secure, scalable and high-volume transaction processing APIs.
- Troubleshoot production issues and analyse transaction logs/API responses.
- Handle transaction failures, timeouts, duplicate transactions and idempotency.
- Participate in code reviews, solution design,



SIT/UAT and production releases.
- Support performance testing, monitoring and production troubleshooting.
- Follow applicable payment security, coding and compliance standards.

Required Technical Skills

- Strong hands-on Core Java.
- Java 8/11/17+.
- Spring Boot, Spring MVC, REST APIs.
- Microservices architecture.
- Third-party API integration.
- SQL and relational databases — MySQL/Oracle.
- JSON, XML, HTTP/HTTPS and API authentication.
- Git and CI/CD.
- Application logging, monitoring and troubleshooting.
- AWS/cloud knowledge is preferred.
- Knowledge of asynchronous processing, messaging and event-driven architecture is an advantage.

Mandatory Payment Domain Experience Practical experience in one or more of:

- Payment Aggregator (PA) / Payment Gateway (PG)
- Merchant Acquiring
- UPI
- Online/offline merchant payments
- Static/Dynamic QR payments
- POS / Soundbox transactions
- Payment callbacks/webhooks
- Refunds and reversals
- Settlement and reconciliation
- Merchant onboarding
- Transaction monitoring and failure handling

Preferred Knowledge

- UPI transaction lifecycle.
- Merchant acquiring ecosystem.
- QR and Soundbox transaction architecture.
- Payment switch/processor integrations.
- Idempotency and duplicate transaction handling.
- Fraud/risk checks.
- PCI-DSS and payment security.
- Encryption, masking and secure payment/customer data handling.

Work Mode: Onsite

Employment Type: Contract

Experience: 4–6 Years

Interested candidates can apply through LinkedIn with their updated resume.

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