I build secure APIs and enterprise systems in Java & .NET, and lead the team shipping them for clients across Japan.
Profile
About
I'm a software engineer with 3+ years building secure APIs and enterprise web applications. I lead a development and QA team at SoftSora, study Software Engineering at SLIIT, and ship my own commercial software through SUNDEVS.
Most of my work serves clients across Japan, from car-marketplace platforms to AI-driven sales tooling. I care about systems that are fast, dependable, and genuinely useful.
Experience
Completed
Career
SoftSora · Nugegoda SoftSora · Colombo SoftSora · Colombo
Sundevs · Sri Lanka
Summit Realms · RemoteBehind the work
Life at SoftSora: shipping with the team, conferences, and the occasional award.
Selected work
Enterprise client systems for companies across Japan, plus open-source tools used at scale.
Full-Stack · AWS
Replaced a manual Excel/email buyer-registration process for a Japanese car-marketplace with a self-service web platform: registration, car-matching preferences, a personal dashboard, and match notifications.
→ 1,000+ buyers onboarded.
Architecture · Performance
Re-architected a static, hard-to-update vehicle dataset into a dynamic model on S3 + CloudFront with an EC2 microservice, while keeping the pre-loaded speed.
→ Publishing time cut from days to hours; sub-1ms reads.
AI · Sales Tooling
An engine that reads a client's own records plus dozens of public signals (site health, reviews, social activity, competitor ranking, seasonality) and generates timely, context-aware proposals tuned to the local Japanese market and industry.
→ Hour-long research reduced to seconds, consistently.
Data Engineering · AI
Merged three disconnected contact sources into one CRM, enriched ~6,000 bare records, and normalized 79 job-title variations to auto-sort decision-makers.
→ 3,000+ decision-makers identified; enrichment ran for a few dollars.
Backend · Systems
A self-hosted gateway between systems that need approval and the people who give it. It posts interactive Approve/Reject messages to Slack, applies a rule, and notifies the source system.
→ Approvals from minutes to seconds; fully audited.
Open-Source · Security
A real-time security plugin that monitors Minecraft operator accounts for compromise and unauthorized access, alerting admins before damage is done.
→ 19,000+ servers protected · 75+ GitHub stars.
Automation
One click after an appointment is confirmed generates a full research pack (company, website, and Google Maps audit), filed and delivered before the meeting.
Automation · n8n
A daily engine that scrapes job sites, normalizes messy Japanese company names, dedupes against the client DB, and files genuinely new leads automatically.
CRM Integration
Every Monday, deals closing that week are pulled from HubSpot and posted to Google Chat, full automation despite a no-automation HubSpot plan.
Platform · SaaS
A unified customer platform (licenses, servers, requests, scheduling, and a 20-state support chatbot) that shifted support from reactive to 24/7 self-service.
Open-Source
Live Minecraft leaderboards in Discord via PlaceholderAPI & webhooks. My first commercial product, and the foundation for starting SunDevs.
Open-Source
A config-driven event system for Minecraft servers: live leaderboards, boss-bar HUD, and automated rewards for timed competitive events.
Shipped & selling
Software I build and sell through SUNDEVS. Click to view in the store.
Create, validate, and control software license keys, with a Java API, Discord bot, and docs.
Wraps ProGuard & yGuard to make Java code unreadable, from one simple dashboard.
Self-hosted paste sharing with access controls, a REST API, and an admin panel.
Self-hostable URL shortener with your own domain, click tracking, and analytics.
Toolkit
Java
C#
JavaScript
TypeScript
Spring Boot
ASP.NET
NestJS
Hibernate
Thymeleaf
MySQL
MongoDB
Redis
Oracle DB
AWS
Oracle Cloud
Docker
Kubernetes
Kafka
Nginx
Claude AI
Gemini
n8n
Selenium
Git
GitHub
HubSpot
Zoho CRM
Education
Certifications
Click a certificate to view it
SLIIT Dean's List Award
Year 1 Semester 2 and Year 2 Semester 2. Click a photo to view.
Get in touch
Open to backend & full-stack roles and collaboration. Reach me at kasun@hapangama.com.