abhimanyu kumar

Technical Lead or Senior Java Backend

Hazaribagh, Jharkhand, India 6+ yrs exp 90 · Outstanding

About

Seeking Technical Lead or Senior Java Backend opportunities focused on Java, Spring Boot, Kafka, AWS, Microservices, Cloud, REST APIs, and event-driven architecture, where I can contribute technical leadership, scalable system design, and enterprise software development expertise. I am also interested in Python, Rust based development. As fresher I can work on data engineering, devops.

Skills & Expertise (46)

AWS Advanced

8.0/10

Years Exp

Python Intermediate

7.0/10

Years Exp

Node.js Intermediate

7.0/10

Years Exp

Thread Pools ELK Stack Openapi Monolithic Multi-Module Factory Strategy Singleton Proxy Adapter Resilience4j IAM OAuth2 OIDC HTTPS OWASP guidelines Spark Streaming Airflow DVC Parquet Delta Lake Flink Apache Kafka C/C++ Rust Scala Data Structure and Algorithm Bash PowerShell JavaScript Spring Security JPA JasperReports S3 Kafka Connect JDBC Elasticsearch Kafka Streams Prometheus TLS Apache Storm EC2 VPC

Work Experience

Software Developer

Analytiq Business Ventures

Sep 2022 - Feb 2023

Built secure, scalable payment infrastructure handling real-time financial transactions. Designed and developed PAYIN, PAYOUT, and ADMIN APIs for merchant onboarding, transaction processing, settlement tracking, and reporting. Implemented JWT-based authentication and authorization using Spring Security, enforcing identity verification on every API request. Implemented role-based access control (RBAC) using JWT claims, enabling fine-grained authorization for Admin, Merchant, and Support users. Designed JWT tokens with claims such as subject (sub), issuer (iss), audience (aud), roles, and expiry (exp), ensuring APIs accepted only intended and valid tokens. Implemented asymmetric JWT signing (RS256), where tokens were signed using private keys and validated by downstream microservices using corresponding public keys, eliminating shared-secret based authentication. Enabled local JWT validation within microservices by verifying signature, issuer, audience, roles, and token expiry without runtime dependency on the authentication service. Secured service-to-service communication using HTTPS/TLS and identity-based authorization across distributed microservices. Implemented API rate limiting, audit logging, and transaction traceability to support operational monitoring and compliance requirements. Designed Kafka-driven asynchronous payment workflows for transaction processing, notification handling, settlement orchestration, and event propagation. Implemented Debezium CDC with the Outbox Pattern to ensure reliable event publication, atomicity between database updates and Kafka events, and eventual consistency across services. Built Elasticsearch-based transaction search and reporting modules, reducing report generation latency by approximately 80%. Developed a Storm + Kafka fraud-detection pipeline capable of processing more than 15,000 transaction events per second for real-time risk analysis and anomaly detection. Participated in payment gateway integrations, webhook processing, refund workflows, transaction reconciliation, and merchant settlement operations.

Senior Java Developer

Appizum Technology

Jan 2019 - Aug 2022

Architected and developed modular microservices for cart, checkout, payment, and delivery. Leveraged RabbitMQ for notification delivery and Redis for session storage and rate limiting. Enabled Elasticsearch-based search on menu items and restaurant metadata. Integrated OAuth2/JWT based login and RBAC with Spring Security. Wrote extensive test coverage with JUnit5 & Mockito; integrated with Postman automated suites. Designed API contracts and documented all endpoints using Swagger/OpenAPI. Conducted query profiling and optimization to improve DB performance and resolve timeouts. Guided junior developers and contributed to code reviews, refactoring, and mentorship.

Java Developer

Strategic outsourcing services [client: JAPIT]

Oct 2018 - Dec 2018

Developed backend modules for the government training scheme tracking. Used Spring MVC and Hibernate with custom HQL/native SQL for complex queries. Designed JasperReports-based dynamic PDF generation and automated email delivery. Configured role-based access control and user session management. Ensured data integrity, input validation, and exception handling across all modules.

Software Engineer

ITZ Software Technologies

Apr 2015 - Mar 2017

Developed REST APIs for a Doctor Appointment Booking System with dynamic slot scheduler with payment integration. Integrated payment gateway APIs with support for refunds and transaction audits. Fixed N+1 query issues and used Hibernate second-level caching to improve performance. Designed and deployed services to AWS EC2, managed AMIs and environment configurations. Built internal tools for doctor availability tracking and admin reporting. Improved performance via caching and query optimization. Deployed applications on AWS EC2.

Junior Developer

Avancosys

Nov 2012 - May 2013

Contributed to social platform “SkillThrust” with features like chat, geolocation, and reviews. Used Google Maps API for live tracking and calendar scheduling for events. Implemented OTP-based registration, social login (Google/Facebook), and access control. Created validation utilities to handle anti-spam, input sanitization, and secure storage. Supported deployment using AWS EC2/S3, worked closely with the frontend team (JSP/jQuery).