Open to opportunities

Chandan Kumar

@chandankumar19

Message

I build reliable payment-processing microservices and distributed backend systems in Java.

India

Message

What I'm looking for

I'm looking to build reliable, high-scale backend and distributed systems, especially event-driven payment or transaction platforms, while owning production performance, observability, and system reliability.

At Zeta, I own and maintain a PostgreSQL-backed, Apache Flink-powered ACH processing platform that handles millions of ACH transfers and generates NACHA files for merchant settlements. I reduced service cold-start p99 latency from 10 seconds to 300ms by improving connection reuse, startup warm-up, and asynchronous execution.

I instrumented ACH connector services with Prometheus and Grafana to speed recurring incident diagnosis, and optimized a Drools rule engine supporting 10+ configurable transaction-processing flows.

Previously at ZopSmart, I contributed to a 20+ microservice Spring Boot backend, built Kafka-driven workflows, deployed Kubernetes services with Helm, reduced endpoint latency by 50%, and created CI/CD validation pipelines that reduced deployment rollback rates by 70%.

Experience

Work history, roles, and key accomplishments

Current

Software Development Engineer II

Current

Zeta

Jul 2026 - Present (1 month)

Own and maintain a PostgreSQL-backed, Apache Flink-powered ACH processing platform on a multi-tenant system, handling distributed processing of millions of ACH transfers including NACHA file generation for merchant settlements. Diagnosed a service cold-start latency issue, reducing p99 from 10s to 300ms, and instrumented the ACH connector service with Prometheus metrics and Grafana dashboards.

Java Spring Boot PostgreSQL Apache Flink Kafka Kubernetes Docker Helm Prometheus Grafana Drools Multi Tenant Services Distributed Systems Performance Optimization

Software Development Engineer I

Zeta

Sep 2025 - Jul 2026 (10 months)

Owned and maintained a PostgreSQL-backed, Apache Flink-powered ACH processing platform on a multi-tenant system, handling distributed processing of millions of ACH transfers including NACHA file generation for merchant settlements. Optimized a Drools-based rule engine powering 10+ configurable transaction-processing flows, reducing duplicated business logic and engineering effort.

Java Spring Boot PostgreSQL Apache Flink Kafka Kubernetes Docker Helm Prometheus Grafana Drools Distributed Systems Performance Optimization

Software Development Engineer

ZopSmart

Jul 2024 - Jul 2025 (1 year)

Contributed to a distributed Spring Boot backend spanning 20+ microservices, building event-driven workflows with Kafka and securing service-to-service communication with Spring Security. Deployed and maintained services on Kubernetes using Helm, refactored legacy transaction modules to cut request latency by 50%, and built CI/CD pipelines reducing deployment rollback rate by 70%.