Raj Kumar Sony
Available for Work  |  Osaka, Japan  |  4+ Years Exp

Raj Kumar Sony

// Java Backend Engineer · Fullstack Developer · AI Integrator

I build systems that solve real world problems using tech

Specializing in Cloud-Native Architectures, Spring Boot Microservices, and AI/LLM Integration. Building distributed services that scale — from Osaka to the world.

core-backend:8081
ai-inference:8085
infra-service:9090
auth-gateway:8443
event-broker:9092
Explore Stack →Hire on UpworkPublish Message Resume
Event Bus
POST
GET
PUT
EVENT
gRPC
// Cluster Metrics · Production Outcomes
0%
API Latency Reduction
PHP → Spring Boot Migration
0%
User Engagement Boost
GPT-4 + LangChain Integration
0%
Faster Release Cycles
CI/CD · Jenkins · GH Actions
0%
Infrastructure Cost Savings
AWS Optimization
0+
Years of Experience
Java · Spring · AWS
0%
Scalability Increase
Microservices Architecture
0%
MTTR Reduction
CloudWatch Monitoring
0
Production Deployments
PLAN-B Inc · Japan
01.

Tech Stack Orchestration

// Registered microservices in the Eureka discovery cluster

service-id
core-backend
Port
:8081

Core Service

Java 17+, Spring Boot, Spring Cloud, Spring MVC, Hibernate ORM, JPA, MyBatis, Lombok, JUnit, Mockito.

JAVA 17SPRING BOOTHIBERNATEJUNITMOCKITO
Health99.9%
service-id
ai-inference
Port
:8085

AI/LLM Integration

OpenAI GPT-4, LangChain orchestration, Python scripts, AI-driven content optimization pipelines for B2B SaaS.

GPT-4LANGCHAINPYTHONOPENAI API
Health99.5%
service-id
persistence-layer
Port
:5432

Persistence Layer

MySQL, PostgreSQL, MongoDB, Redis for distributed caching and sessions. DynamoDB on AWS for serverless storage.

POSTGRESQLMONGODBREDISDYNAMODB
Health98.1%
service-id
infra-orchestrator
Port
:9090

Infrastructure

Docker, Kubernetes, Jenkins, GitHub Actions, CI/CD pipelines. AWS EC2, S3, RDS, VPC, ELB, Route 53, Amplify.

DOCKERKUBERNETESJENKINSAWSGH ACTIONS
Health100%
service-id
auth-gateway
Port
:8443

Auth Gateway

Spring Security, OAuth 2.0 (Okta, Auth0), JWT lifecycle, CORS/CSRF protection, encryption & validation.

OAUTH 2.0JWTOKTASPRING SEC
Health100%
service-id
api-gateway
Port
:8080

API & Integration

RESTful APIs, Feign Client, Rest Template, API Gateway, Eureka Server, HATEOAS, Swagger/OpenAPI docs.

REST APIEUREKAFEIGNSWAGGER
Health97.3%
// Proficiency Matrix
Java / Spring Boot95%
AWS Cloud Services88%
Microservices / Docker / K8s85%
PostgreSQL / MySQL / MongoDB87%
AI/LLM Integration (GPT-4)80%
CI/CD · Jenkins · GH Actions85%
OAuth 2.0 · JWT · Security88%
React / JavaScript / Python75%
// Inter-Service Communication Flow
CLIENTAPI GATEWAY:8080AUTH SVC:8443CORE SVC:8081POSTGRES:5432GPT-4 / AI:8085AWS S3 / RDScloudHTTPJWTRESTSQLAIS3
02.

Deployment History

(Work Experience)

// Production environments where services have been running

// company.name
PLAN-B, Inc.
Software Engineer – Java Backend / SaaS
Osaka, Japan
Feb 2023 – Present
2+ years
▸Architected scalable B2B SaaS backend services using Java, Spring Boot, and AWS microservices, increasing system scalability by 40% while leading full SDLC.
▸Integrated OpenAI GPT-4 and LangChain to deliver AI-driven content optimization, boosting user engagement by 70%.
▸Migrated legacy PHP platforms to Spring Boot microservices, reducing API latency by 60% and server costs by 35%.
▸Automated CI/CD pipelines with Jenkins, GitHub Actions & CloudWatch — reducing release time by 50% and MTTR by 40%.
JAVASPRING BOOTGPT-4LANGCHAINAWSDOCKERJENKINSMICROSERVICES
// company.name
Cognizant Technology Solutions
Programmer Analyst – Java Full Stack Engineer
Bangalore, India
Mar 2022 – Jan 2023
10 months
▸Enhanced Healthcare IT Tracking System using Java, Spring Boot, Angular, and MySQL — improving end-user experience by 30%.
▸Improved AWS resource utilization by 40% and reduced data retrieval time by 35% via MySQL query optimization and indexing.
▸Designed RESTful APIs with Swagger; delivered 20% faster releases through Agile/Scrum and improved team-client communication by 25%.
JAVASPRING BOOTANGULARMYSQLAWSSWAGGERHEALTHCARE IT
03.

Service Registry

(Production Projects)

// Eureka-registered production instances

▶
instance-id · P-001
SEO Content Optimisation
B2B SaaS Platform
LIVE · prod
Upwork · Freelance

Backend lead for an AI-powered SEO content platform. Built scalable microservices in Java & Spring Boot on AWS, integrated OpenAI GPT-4 and LangChain for content generation, designed REST APIs, database models, and background jobs. Improved content engagement by ~70%.

JAVASPRING BOOTGPT-4LANGCHAINAWSMICROSERVICESREST APIs
Role
Java Backend Engineer
AI Stack
GPT-4 · LangChain
Impact
+70% engagement
// Architecture Flow
CONTENTBRIEFinputAPIGATEWAY:8080KEYWORDANALYSIS:8081BRIEF SVC:8082GPT-4 +LANGCHAINAI draftingREPORTSVC:8083EC2 + ELBload balanceRDS + S3storageCLOUDWATCH
▶
instance-id · P-002
Influencer Marketing Platform
Microservices Migration
LIVE · prod
Upwork · Freelance

Migrated legacy PHP monolith to Spring Boot microservices on AWS. Designed & implemented secure REST APIs with Spring Security, improved database queries, and supported deployment & monitoring. New architecture reduced API latency by ~60%.

PHP → JAVASPRING BOOTSPRING SECURITYAWSPROMETHEUSMICROSERVICES
Migration
PHP → Spring Boot
Auth
Spring Security · JWT
Impact
-60% latency
// Migration Architecture
LEGACYPHPMONOLITHHigh Latency→SPRING CLOUDGATEWAYSpring SecurityDISCOVERY:8081MANAGEMENT:8082REPORTSPAYMENTS:8083RDSoptimizedAWSEC2ELBS3PROMETHEUS+GRAFANAmonitoring
▶
instance-id · P-003
Compliance & Screening App
Full Stack Web Application
LIVE · prod
Upwork · Freelance

Compliance & screening web app for businesses to check customers and partners. Designed Spring Boot backend, REST APIs, React frontend, database design, integrations, and AWS deployment. Improved processing speed with a clear dashboard for reviewing screening results.

JAVASPRING BOOTREACTPOSTGRESQLAWS EC2/LAMBDA
Stack
React + Spring + AWS
DB
PostgreSQL
Result
Fast Processing
// Full-Stack Architecture
BUSINESSINPUTdataREACTFRONTENDDashboard UISPRING BOOTBACKENDREST APIs :8080DATAintegrationsPOSTGRESQL:5432AWS EC2 + LAMBDA✓ CLEARED✓ CLEARED⚠ REVIEW✗ HIGH RISKcomplianceDASHBOARD13,753screenings
▶
instance-id · P-004
Local Services Discovery
& Booking Platform
LIVE · prod
Upwork · Freelance

Local services discovery & booking platform. Users search nearby businesses, view details/reviews, and place booking or inquiry requests. Built Java/Spring Boot REST APIs, business logic, MySQL database design, React frontend, and AWS Amplify deployment.

JAVASPRING BOOTREACTMYSQLAWS AMPLIFY
Endpoint
POST /bookings
Maps
Google Maps API
Result
Smooth UX · Fast Booking
// Platform Workflow Journey
1. USERSEARCHNearbySPRING BOOTREST APIsBusiness LogicDB DesignJSON :8080BUSINESSPROFILEMYSQL:33063. BOOKINGREQUESTCalendarSelectionPLACE REQUESTREACTFRONTEND:3000AWS AMPLIFYdeployment4. TRACKING✓ Confirmed✓ Scheduled✓ CompleteDashboard
▶
instance-id · P-005
YouDrive
Universal Cloud Drive Manager
LIVE · prod
Upwork · Freelance

Universal cloud drive manager connecting Google Drive, Dropbox, OneDrive, Box into one unified interface. Designed backend with Spring Boot microservices, Spring Cloud, Kafka, PostgreSQL, MongoDB, Redis, and Keycloak. Uses CQRS and Saga patterns for cross-drive operations.

SPRING BOOTKAFKAPOSTGRESQLMONGODBREDISAWS ECSKEYCLOAKCQRS · SAGA
Providers
GDrive · Dropbox · Box
Patterns
CQRS · Saga · Eureka
Deploy
AWS ECS · Scalable
// High-Level Backend Architecture
Google DriveDropboxOneDriveBoxAPI GATEWAYSpring CloudKeycloak:8080ACCOUNT SVC:8081FILE METADATAMongoDB :8082STORAGE PROVadapters :8083WORKER/SYNCEUREKAdiscoveryCONFIG SVRcentralizedKAFKACQRSSAGAPOSTGRESQLuser dataMONGODBfile metadataREDIScache/sessionAWS ECSElasticContainerService
▶
instance-id · P-006
Invisible Browser
AI Personal Assistant
LIVE · background
Upwork · Freelance

Invisible background browser for an AI personal assistant, built with Electron. Exposes a clean API for the AI to search, navigate, and extract content. React frontend for debug view. MongoDB stores browsing sessions, page metadata, and extracted snippets. Focused on reliable automation and error handling.

REACTELECTRONMONGODBOpenAI APIAUTOMATION
Runtime
Electron · Background
Storage
MongoDB · Sessions
Result
Automated · Reliable
// Background Automation Architecture
AI ASSISTANTOpenAI APISearch/ExtractINVISIBLEBROWSER(Electron)BackgroundProcessWEB NAVsite.com · etcCONTENTextractionAPI DESIGNSESSION +PAGE METAsess_001sess_002..MONGODBsessionspage metasnippetsREACTDEBUG VIEWSessions ListLog Console
▶
instance-id · P-007
E-commerce Platform
Microservices Architecture
LIVE · prod
Upwork · Freelance

Complete ecommerce backend with microservices for catalog, cart, orders, payments, users, and notifications. API Gateway, Eureka, Config Server, Kafka event-driven messaging with CQRS and Saga patterns for order flows. Secure auth with JWT/Keycloak.

JAVASPRING BOOTKAFKAPOSTGRESQLMONGODBREDISKEYCLOAK/JWTCQRS · SAGA
Services
6 microservices
Patterns
CQRS · Saga · Eureka
Result
Scalable · Secure
// Complete Microservices Architecture
CLIENTWebMobileRESTAPI GATEWAYSpring CloudKEYCLOAKJWT Auth:8080CATALOG SVCMongoDB+RedisCART SVCRedisORDER SVCPostgreSQLPAYMENT SVCPostgreSQLKAFKAEvent-DrivenCQRSSAGAORDER SVCTrackingPAYMENT SVCSecureUSER SVCProfilesNOTIF SVCMongoDB · EmailEUREKADiscoveryCONFIG SVRCentralizedDATABASESPostgreSQLMongoDBRedis
04.

Boot Configuration

(Education)

// System init dependencies — academic layer

// degree
MCA
CMR Institute of Technology (CMRIT)
Bangalore, Karnataka
Aug 2019 – Sep 2022CGPA: 8.4 / 10
// degree
BCA
Sachchidanand Sinha College
Aurangabad, Bihar
May 2015 – Oct 201870.75%
// External Profiles & Verification
GitHub
rajkumar-sony
LinkedIn
rajkumarsony
Upwork
Hire Me
HackerRank
rajkumarsony