Java Developer | Payment Aggregation / Merchant Payments

We are looking for an experienced Java Backend Developer with 4 to 6 years of hands-on experience in Payment Aggregation (PA), Payment Gateway (PG), UPI, and merchant payment systems.

The candidate should have strong experience in Java, Spring Boot, REST APIs, Microservices, SQL, and third-party payment integrations, along with practical understanding of online and offline merchant payment flows such as UPI, QR, POS, Soundbox, refunds, reversals, callbacks, settlement, and reconciliation.

Key Responsibilities

• Design, develop, and maintain backend applications using Java and Spring Boot.
• Develop and integrate REST APIs for Payment Aggregator and Payment Gateway platforms.
• Implement end-to-end online and offline merchant payment flows.
• Work on UPI, Static/Dynamic QR, POS, Soundbox, and payment gateway integrations.
• Develop merchant onboarding and transaction processing services.
• Implement 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 service providers.
• Develop secure and scalable transaction APIs for high-volume payment processing.
• Implement transaction lifecycle handling including initiation, authorization, success/failure, timeout, reversal, refund, and settlement.
• Implement appropriate validation, exception handling, logging, and security controls.
• Troubleshoot production payment failures and third-party integration issues.
• Analyze transaction logs and API responses and perform RCA.
• Participate in code reviews, technical discussions, SIT/UAT, and production releases.
• Support performance testing and production monitoring.
• Follow applicable payment security and coding standards.

Mandatory Technical Skills

• Core Java
• Java 8/11/17+
• Spring Boot / Spring MVC
• REST APIs
• Microservices
• SQL and relational databases
• MySQL / Oracle
• JSON / XML
• HTTP / HTTPS
• API authentication
• Third-party API integration
• Git
• CI/CD
• Application logging and troubleshooting

Mandatory Payment Domain Experience

Candidates should have hands-on experience in one or more of:

• Payment Aggregator (PA)
• Payment Gateway (PG)
• Merchant Acquiring
• UPI
• Online payment processing
• Offline merchant payment processing
• Static / Dynamic QR
• POS
• Soundbox
• Payment callbacks / webhooks
• Refunds and reversals
• Settlement and reconciliation
• Merchant onboarding
• Transaction monitoring and failure handling

Preferred Skills

• UPI transaction lifecycle
• Merchant acquiring ecosystem
• QR and Soundbox architecture
• Payment switch / processor integrations
• Idempotency and duplicate transaction handling
• Fraud/risk checks
• PCI-DSS concepts
• Encryption and masking of payment/customer data
• Kafka / messaging / event-driven architecture
• AWS

Ideal Candidate

The ideal candidate is a Java Backend Developer with genuine production payment-domain experience, capable of developing scalable payment APIs, integrating external payment systems, understanding merchant transaction flows, and troubleshooting transaction-level issues.