Abhishek Kumar Java Backend Developer

Java Backend Developer — Bengaluru, India (Remote)

Abhishek
Kumar

Java backend developer building Spring Boot microservices, REST APIs, event-driven workflows and real-time services for e-commerce and last-mile delivery.

Spring Boot Kafka Redis Microservices
View Projects Download Resume
Abhishek Kumar
Fig. 01 Abhishek Kumar
Fig. 02 — Service topology Live
Service architecture overview A client reaches a Spring Boot service layer over HTTP. That layer is backed by Kafka for the event stream, Redis for caching and rate limits, PostgreSQL as the relational store and Cassandra for wide-column writes. Client HTTP Spring Boot Service REST · Security · WebSocket · Events Kafka Event stream Redis Cache & limits PostgreSQL Relational Cassandra Wide-column

Request path · Spring Boot services · Kafka · Redis · PostgreSQL · Cassandra

01

Selected Work

Solo, end-to-end ownership

01.1

PulseGate

Reactive API gateway on Spring WebFlux

Java Spring WebFlux Redis Lua Prometheus Grafana

Problem

Rate limits have to hold across replicas rather than per instance, and the gateway needs to shed load before one slow dependency takes the service down with it.

Built

Atomic Redis Lua scripts implementing token-bucket, sliding-window and fixed-window limiters that stay correct across replicas. An adaptive circuit breaker, a live WebSocket dashboard for gateway state, and Prometheus + Grafana instrumentation. Load-tested with Artillery.

Read case study GitHub

01.2

HandOff

AI agent supervision platform

Java 21 Spring Boot 3 PostgreSQL Flyway React 19 TypeScript Vite

Problem

Once an AI agent acts on real support tickets, you need to see what it is doing, stop it at the right moments, and be able to show afterwards exactly what happened.

Built

A supervision layer for AI agents on support tickets: live monitoring, human approval gates before consequential actions, and an audit trail. Security covers JWT + RBAC, refresh-token rotation with reuse detection, Redis-backed rate limiting and single-use WebSocket tickets. Java 21 and Spring Boot 3 on PostgreSQL with Flyway migrations, React 19 and TypeScript on the front end.

Read case study GitHub

01.3

Cognitive API Agent

Python Streamlit OpenAI Pydantic-AI

Problem

Calling an API usually means reading docs and writing the request by hand. This tool lets you describe what you want in plain English.

Built

An AI tool that turns plain English into API calls. A reasoning layer checks the request is valid, and the user confirms before anything is executed. Built with Python, Streamlit, OpenAI and Pydantic-AI.

Live demo GitHub

02

Experience

Backend engineering

Jul 2024 — Present
Remote

Backend Software Engineer

Speedbae Digital Pvt. Ltd. · E-commerce and Last-Mile Delivery Startup
Client project: Exotyq, an artisan marketplace (shop.exotyq.com)

  • Order APIs: Built order-lifecycle and rider-assignment APIs with Java 17, Spring Boot, Spring Data JPA and MySQL. Found and fixed N+1 query problems using batch fetching.
  • Catalog Caching: Added Redis cache-aside for catalog endpoints and stock-update handling, to cut repeated database reads and keep inventory data consistent.
  • Webhook Processing: Built Kafka consumers for Shopify order and refund webhooks, with idempotent processing and dead-letter handling for failed events.
  • Catalog Ingestion: Automated vendor product-feed ingestion to reduce manual catalog onboarding work.
  • Real-Time Rider Tracking: Stored rider GPS updates in Cassandra and sent live order updates over WebSocket.
  • CI/CD: Containerized services with Docker and set up Jenkins pipelines for repeatable builds, deployments and rollbacks.

Java 17 Spring Boot Spring Security Kafka Redis MySQL Cassandra Shopify APIs Docker AWS S3 WebSocket Jenkins ELK Stack

Nov 2023 — Jan 2024
Jamshedpur, India

Java Developer Intern

Speedbae Digital Pvt. Ltd.

  • Built and tested Spring Boot REST APIs for order and rider modules using Spring Data JPA, JUnit 5 and Mockito.
  • Added JWT authentication filters for protected endpoints, documented APIs with Swagger/OpenAPI, and set up Jenkins CI test runs.

03

Skills

Tools of the trade

Languages & Frameworks

Java 17 Spring Boot Spring Security Spring Data JPA REST APIs WebSocket

Data & Messaging

MySQL Cassandra Redis Kafka Shopify APIs

Platform & Delivery

Docker AWS S3 Jenkins ELK Stack JUnit 5 Mockito Swagger/OpenAPI

04

Education

Education & certifications

Oct 2020 — Jun 2024

B.Tech, Computer Science & Engineering

Chaibasa Engineering College

CGPA 7.93/10

05

Contact

Let’s connect

Building thoughtful backend systems from Bengaluru, India (Remote).

Email Abhishek