Dhruv Kumar

Senior Java Backend Engineer with 4+ years designing and shipping event-driven microservices and distributed systems for high-security fintech and enterprise platforms. Currently building high-throughput payment gateway and transaction processing systems at OMISE for 500K+ users under PCI-DSS compliance. Deep expertise in Java 17/21, Spring Boot, Spring Data JPA, Hibernate, Apache Kafka, REST APIs, PostgreSQL, MySQL, Redis, and AWS (EKS, Lambda, S3, RDS).

Measurable impact: 30% lower API latency, 99.9% message-delivery reliability, and 40% reduction in inter-service coupling through clean, observable, resilient architecture.

Senior Java Backend Developer - OMISE Payment Gateway (via TAD International) - Remote — Bangkok, Thailand

(2025-06 - 2026-02)

Fintech · PCI-DSS Environment

• Architected a decoupled Card Brand microservice using Spring Boot and Apache Kafka, enabling asynchronous event-driven processing and reducing inter-service coupling by 40%; hardened inter-service calls with Resilience4j (circuit breaker, retry, bulkhead) for fault isolation under partial outages.
• Implemented the SAGA pattern (orchestration-based) with compensating transactions to guarantee data consistency across distributed payment, settlement, and notification services, eliminating partial-failure inconsistencies in multi-step transaction flows.
• Optimized the core transaction engine through Redis caching and SQL query tuning, cutting API response latency by 30% across high-traffic payment endpoints handling thousands of concurrent transactions.
• Built a real-time Kafka notification system with custom partitioning, consumer-group management, and offset tracking, achieving 99.9% message-delivery reliability.
• Engineered end-to-end observability — distributed tracing (OpenTelemetry to Jaeger) propagated across asynchronous Kafka boundaries, plus Prometheus and Grafana dashboards and centralized ELK logging — with RED-method alerting that accelerated incident root-cause analysis.
• Implemented enterprise IAM with Keycloak (OAuth2 / OIDC / JWT) for centralized identity management across a multi-tenant platform securing 500K+ users.
• Established CI/CD pipelines with Jenkins and GitHub Actions — automated testing, Docker builds, and zero-downtime Kubernetes deployments on AWS EKS.
• Engineered a security-critical microservice for wireless POS device registration using Server-Sent Events and OTP-based authentication with ephemeral Redis keys, achieving zero unauthorized registrations in production.

Java Backend Developer - DigiTele Networks - Hyderabad, India

(2022-04 - 2025-05)

Enterprise Products

• Refactored a legacy monolith into modular Spring Boot microservices, improving application performance by 40% and enabling independent deployability.
• Designed a microservices-based scheduling system on PostgreSQL, coordinating resources across 100+ users with conflict detection that prevents double-booking.
• Optimized the PostgreSQL schema with indexing strategies for concurrent booking, achieving millisecond-level response under peak traffic.
• Integrated an API Gateway with OAuth2 / OIDC for authorized access control across all endpoints.
• Built real-time data-visualization REST APIs for forecast-scheduling metrics consumed by business stakeholders.
• Automated bulk data import/export workflows, reducing manual data-entry time by 50%.
• Mentored 3 junior developers on clean architecture and code-review practices, reducing post-release defect rate by 90%.

B.Tech - Computer Science Engineering - R.B.S. Engineering Technical Campus, Agra (2018 - 2022)