AVAILABLE FOR OPPORTUNITIES

Visura
Chandula.

// seeking junior & graduate roles

Learning by building real systems — REST APIs, microservices, event-driven architecture, and distributed systems. Interested in software engineering, business analysis, and any technology role where I can add value.

View Projects GitHub ↗ LinkedIn ↗

// PROJECTS

What I've Built.

// FINTECH MICROSERVICES ECOSYSTEM

Four microservices built as one connected system. The banking API is protected by a standalone rate limiter via HTTP, produces transaction events consumed by a fraud detection service via Kafka, and offloads async work to a job queue worker.

Fintech Microservices Ecosystem

Four services — one connected system

Microservices Distributed Rate Limiting Event-Driven Apache Kafka Redis Spring Boot PostgreSQL Docker

// SERVICE COMMUNICATION

CUSTOMER REQUEST

↓

// PROTECTION LAYER

rate-limiter-service

HTTP sync

↔

before each request

// CORE SERVICE

banking-core-api

Kafka async

→

after transaction

// ANALYSIS LAYER

fraud-detection-service

HTTP · submit job

↓

// ASYNC WORKER

job-queue-service

// SERVICE 01 · PROTECTION

rate-limiter-service

Standalone distributed rate limiter. Token Bucket via atomic Redis Lua script. Resilience4j circuit breaker fails open on Redis outage. Java SDK for one-dependency integration.

Spring Boot 3 Redis Lua Resilience4j Grafana PostgreSQL

View source

// SERVICE 02 · CORE

banking-core-api

Production-grade banking REST API. Double-entry ledger, idempotent transactions, optimistic locking, Redis-cached balances, and Kafka event production on every transaction.

Java 21 Redis Kafka JWT PostgreSQL

View source

// SERVICE 03 · ANALYSIS

fraud-detection-service

Real-time Kafka consumer evaluating transactions against a Strategy-pattern rule engine — velocity checks, large amounts, duplicate detection, off-hours activity.

Java 21 Kafka Prometheus Grafana PostgreSQL

View source

// SERVICE 04 · ASYNC WORKER

job-queue-service

Database-backed async job processor with a polling worker, exponential-backoff retries, and dead-letter queue. Handles SEND_EMAIL, SEND_WEBHOOK, and GENERATE_PDF jobs. Ships with a Java SDK client for one-dependency integration.

Spring Boot 3 Java 21 PostgreSQL SDK Client

View source

// CURRENTLY BUILDING

// IN PROGRESS

BUILDING

payment-processing-platform

The four microservices above represent a single bank — one ledger, one set of accounts, one institution (think Barclays). This platform sits above multiple independent instances of that ecosystem, each acting as a separate bank (Barclays, Lloyds, HSBC), and orchestrates payments between them. It does not own any accounts or balances — it coordinates money movement across institutions, handles distributed transaction failures with a compensation chain, guarantees exactly-once processing, and notifies merchants of payment outcomes via webhooks.

Java 21 Spring Boot 3 Spring Cloud Gateway Apache Kafka PostgreSQL Redis Saga Pattern Outbox Pattern Event Sourcing Resilience4j Prometheus Docker

View Repository

// OTHER PROJECTS

// PROJECT 05

careers-backend

A cloud-deployed backend built feature by feature while live — every capability grew from a failing integration test and was only shipped once all tests passed through a GitHub Actions pipeline. Covers JWT auth, role-based access for recruiters and candidates, CV uploads to AWS S3 with presigned URLs, and zero-downtime deploys on Render.

Java 21 Spring Boot 3.4 PostgreSQL AWS RDS AWS S3 JWT Docker GitHub Actions Render Swagger

View README & Source

// PROJECT 06

FitWithJack-backend

REST API for a personal training platform where users book one-time sessions and regular classes — with automated SMTP email confirmations on successful bookings. Containerised with Docker and deployed to AWS EC2, with an alternative setup on Elastic Beanstalk and RDS. Connected to a React frontend on Vercel for a fully cloud-deployed production architecture.

Spring Boot Spring Security Docker AWS EC2 AWS RDS Elastic Beanstalk SMTP React Vercel

View README & Source

// PRODUCTS

Beyond the Backend.

A complete full-stack system built for private bus operators in Sri Lanka — covering trip scheduling, crew assignment, fleet document tracking, fuel and cost logging, stock management, maintenance jobs, and financial reporting end to end.

RouteBus

PRODUCTION

Bus Fleet & Operations Management System

Spring Boot Java React Vite PostgreSQL

// SCHEDULING

Trip & Crew Management

Create trips from timetable for route services and private hires. Assign drivers and conductors in advance and update assignments on the fly when plans change.

// FLEET

Document & Cost Tracking

Dashboard alerts for upcoming document expiries — insurance, revenue licences. Log trip costs and fuel per journey to track day-to-day operational spend.

// MAINTENANCE

Stock & Workshop

Full stock management with in/out records. Maintenance jobs with parts assigned from stock, labour tracked, and total costs captured per job.

// REPORTING

Revenue, Costs & Payroll

Generate daily, weekly, and custom period reports for revenue, operating costs, and profit & loss. Commission-based payslip records for drivers and conductors.