Ahmad

Senior Software Engineer

i2c Inc • Full time

Jun 2021 - Present • 5 yrs 3 mos

• Designed and built event-driven payment and card-processing microservices on Java 17/21 and Spring Boot 3, integrating Kafka producers and consumers for asynchronous, high-throughput transaction flows across a large-scale card-issuing platform serving multiple financial institutions. • Architected a multi-threaded Due Date Service processing accounts in parallel batches on every statement date — evaluating payment status against due-date rules at scale with idempotent batch checkpoints for safe restarts, demonstrating deep concurrency and distributed-computing skills. • Built the Delinquent Adjustment Service reconciling late payments against delinquency state, handling partial payments, fee reversals, and downstream status updates with strict transactional consistency across PostgreSQL and Informix. • Implemented OTP authentication and fraud-prevention controls for card transactions (PCI-aligned, replay protection, idempotency keys), hardening the issuing platform’s security posture. • Designed a joint credit-card handling system from scratch — modeling shared cardholder workflows, authorization splits, and statement aggregation using domain-driven design. • Leveraged AI/LLM tools (GitHub Copilot, Claude) daily for code reviews, automated test generation, BDD/Gherkin feature-file authoring, JaCoCo coverage gap analysis, and documentation — significantly accelerating delivery. • Modernized legacy Java/Struts modules to Spring Boot 3 and Java 17/21, introducing TDD with JUnit 5 and Mockito on previously untested code paths