Welcome to my portfolio

Sachin Karunarathna

Software Engineer

Passionate about building scalable and high-performance software solutions using PHP, Laravel,Go,JavaScript, and modern JavaScript frameworks.I specialize in clean architecture, efficient backend systems, API development, performance optimization, and crafting intuitive user experiences through modern technologies.

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Profile

About Me

Software Engineer specializing in full-stack development with a Bachelor of Information Technology from the University of Moratuwa.

I build robust web applications using best technologies there is.

I transform ideas into scalable solutions, combining technical precision with creative problem-solving. My experience spans freelance projects and enterprise environments, always focusing on clean code and exceptional user experiences.

Full-Stack Development

Building end-to-end applications with modern technologies and best practices.

Problem Solving

Turning complex challenges into elegant, scalable solutions.

Collaboration

Working closely with cross-functional teams to deliver exceptional products.

Technologies I work with

JavaScriptReactNode.jsPostgreSQLAWSGitGoTailwind CSSThree.jsRedisBullMQ
TypeScriptNext.jsPythonLaravelDockerFigmaNestJSFramer MotionReduxWordPress
Career

Experience

From internship to architecting enterprise platforms -the roles that shaped how I build software.

Tecnnovates logo

Tecnnovates

Current
Dec 2025 - Present · 9 mosColombo, Western Province, Sri Lanka · Remote

Software Engineer

Full-time
Dec 2025 - Present · 9 mos

Full-stack developer specializing in NestJS & Next.js -building scalable CRM systems, AI-powered features, and WordPress solutions while driving end-to-end architecture, third-party integrations, and deployment.

  • Designed and architected a scalable CRM system from the ground up, implementing a modular architecture using NestJS (backend) and Next.js (frontend) for maintainability and scalability.
  • Collaborated on server deployment and coordinated with external project management workflows, ensuring smooth cross-team delivery and production readiness.
  • Developed a smart AI-integrated filter system, enhancing data discovery and user experience across the CRM platform.
  • Integrated third-party platforms including Meta for Business APIs, enabling seamless business communication and lead management workflows within the CRM.
Application Engineering, Software Design and +14 skills
TECHNOVITY FZC-LLC logo

TECHNOVITY FZC-LLC

Jan 2025 - Feb 2026 · 1 yr 2 mos

Associate Software Engineer

Full-time
Jan 2025 - Feb 2026 · 1 yr 2 mos
  • Designed and developed features across 3 Laravel applications and 2 Next.js frontends, including RESTful APIs, Redux-based state management, and scalable integrations.
  • Engineered PostgreSQL stored procedures, functions, and queries optimized for data processing, reporting, and performance tuning.
  • Built and maintained cron jobs for scheduled automation and backend workflows.
  • Designed and implemented responsive UI components with Tailwind CSS, ensuring modern, user-friendly interfaces.
  • Developed reusable controllers and services to improve maintainability and streamline business logic across modules.
  • Integrated email automation, notifications, and management systems for improved communication workflows.
  • Utilized Redis caching to enhance system performance, scalability, and reliability.
  • Contributed to an asset management and optimization platform, focusing on efficiency, scalability, and enterprise-grade performance.
PHP, Application Engineering and +17 skills
Fiverr logo

Fiverr

Mar 2024 - Feb 2025 · 1 yrSri Lanka · Remote

Freelance Full Stack Web Developer

Freelance
Mar 2024 - Feb 2025 · 1 yr
  • Designed and developed RESTful APIs and backend services to support web and mobile applications.
  • Integrated multiple payment gateways, handling secure transactions, callbacks, and error scenarios.
  • Built and customized WordPress websites, including theme customization, plugin integration, and performance optimizations.
  • Developed new application features and user interfaces based on client requirements and UX considerations.
  • Fixed production bugs and improved existing systems through refactoring and performance tuning.
  • Collaborated with distributed freelance teams, breaking down requirements into manageable tasks and delivering features independently.
  • Worked in both frontend-only and backend-only roles depending on project needs, ensuring smooth integration across the stack.
  • Communicated directly with clients and team members to clarify requirements, timelines, and deliverables.
Website Building, Freelancing and +12 skills
ServerClub logo

ServerClub

Aug 2022 - Dec 2023 · 1 yr 5 mosSri Lanka

IT Consultant

Full-time
Oct 2023 - Dec 2023 · 3 mosSri Lanka · On-site
  • Researched and implemented server OS installations, configurations, and SSL setups for secure hosting environments.
  • Consulted clients to understand requirements, prepared technical quotations, and recommended the most suitable hosting solutions.
  • Oversaw project deployments across technologies such as Next.js, NestJS, Laravel, WordPress, and Spring Boot.
  • Coordinated with the technical support team to assign and resolve client hosting issues effectively.
  • Collaborated closely with company leadership to align IT solutions with business goals and client needs.
  • Utilized cPanel and Plesk for hosting environment management and familiarized with best practices in scalability, performance, and security.
PHP, Site Build and +6 skills

Full Stack Developer

Full-time
Oct 2022 - Oct 2023 · 1 yr 1 moSri Lanka · Hybrid
  • Deployed and maintained projects on Plesk and cPanel hosting environments.
  • Developed and extended Laravel-based applications, implementing new features and business functionalities.
  • Maintained and enhanced company web applications to support internal operations and client needs.
  • Built a Server Cost Calculator using JavaScript, jQuery, and Bootstrap for improved cost estimation.
  • Delivered 4+ client projects, ensuring quality, scalability, and timely delivery.
  • Worked with RESTful APIs, CORS handling, and authentication management for secure integrations.
  • Gained strong knowledge of Bootstrap, database management, and web application architecture.
  • Collaborated with team members, providing support and knowledge sharing to improve project outcomes.
PHP, Laravel and +24 skills

Full Stack Engineer

Oct 2022 - Apr 2023 · 7 mos

Maintained and optimized company websites for performance, security, and responsiveness, resolving hosting and application issues to minimize downtime. Delivered 3+ client projects using Laravel and WordPress, building scalable, user-friendly solutions with Bootstrap and custom plugins.

Web Developer Internship

Full-time
Aug 2022 - Feb 2023 · 7 mosSri Lanka
  • Assisted in developing and maintaining Laravel PHP applications, gaining hands-on experience in backend development.
  • Built and customized WordPress projects for clients, improving their online presence and functionality.
  • Worked with phpMyAdmin for database management, including queries and optimizations.
  • Utilized AJAX, jQuery, and jQuery UI to create dynamic and interactive web features.
  • Designed responsive web pages with Bootstrap, CSS, and modern UI/UX best practices.
  • Integrated RESTful APIs for seamless communication between frontend and backend systems.
  • Learned and applied industry best practices in web development, version control (git), and deployment.
Process

How I Build Solutions

I believe successful software isn't built by writing code first -it's built by understanding the problem completely.

01 -Discover

Every project begins with discovering the real business challenge. I analyze the existing workflow, identify technical and operational bottlenecks, and understand how the current system is being used. I work closely with stakeholders, developers, and end users to ensure the solution addresses real-world needs rather than assumptions.

02 -Design & Validate

Once the problem is fully understood, I design and validate a solution before implementation. This includes evaluating system architecture, identifying potential risks, measuring long-term maintainability, and refining the design until it effectively solves both current and future challenges.

03 -Build & Deliver

During development, I focus on modern, scalable, and future-proof technologies. Large problems are divided into small, manageable milestones, allowing continuous feedback from clients and stakeholders throughout the development lifecycle. Every completed milestone is reviewed and validated before moving to the next.

My Engineering Process

01

Understand the complete business problem

  • Analyze the existing workflow and technical architecture.
  • Identify root causes rather than only addressing symptoms.
02

Research and collaborate

  • Work with stakeholders, developers, and end users.
  • Understand operational requirements, security concerns, and business goals.
03

Design the solution

  • Create system architecture and implementation plans.
  • Evaluate scalability, maintainability, performance, and security.
04

Validate before building

  • Review the proposed solution against real business scenarios.
  • Refine the architecture until it delivers measurable improvements.
05

Build incrementally

  • Break complex projects into manageable milestones.
  • Deliver continuously, gather feedback, and improve throughout development.
06

Deliver future-ready software

  • Implement clean architecture, secure design, and scalable infrastructure.
  • Optimize performance while ensuring long-term maintainability.

Engineering Highlights

The principles that stay constant across every project, regardless of stack or team size.

Clean Architecture

Clear boundaries and separation of concerns, so the codebase stays easy to reason about as it grows.

Secure by Design

Security and operational requirements are considered during design, not patched in after release.

Built to Scale

Infrastructure and data models chosen to handle tomorrow's load, not just today's traffic.

Performance Focused

Bottlenecks are measured and optimized rather than guessed, without sacrificing readability.

Continuous Feedback

Short milestones keep stakeholders informed and let direction change before it becomes expensive.

Long-Term Maintainability

Documented decisions and consistent patterns so the next engineer ships confidently on day one.

Every milestone reviewed and validated before moving to the next.
Case Studies

Featured Problems & Solutions

Real engineering challenges, the decisions behind each solution, and the impact they delivered.

Security & Platform

Enterprise Credential Vault & Knowledge Platform

01

Challenge

Development teams shared infrastructure credentials through chat applications and direct messages. This created security risks, inconsistent access control, limited auditing, and increased the likelihood of credential leakage.

Solution

I analyzed the complete workflow and designed a secure internal platform that combines a collaborative knowledge base with an enterprise credential vault.

  • Two-tier envelope encryption for sensitive secrets
  • Encryption at rest for stored credentials
  • Role-based and tiered access control
  • Centralized credential management
  • Integrated documentation and knowledge sharing
  • Secure access without exposing credentials through messaging platforms

Impact

The platform eliminated insecure credential sharing, significantly improved security, simplified access management, and provided a scalable foundation for securely managing sensitive operational information across the organization.

Architecture

Multi-Tenant Platform Architecture

02

Challenge

A licensed enterprise application required each customer to host its own database for security and compliance. The existing architecture also restricted users to a single tenant per email address, creating operational limitations for organizations managing multiple environments.

Solution

I designed and implemented a scalable multi-tenant architecture with a centralized identity and tenant management layer.

  • Centralized authentication with tenant resolution
  • Multi-tenant request interception
  • Support for multiple tenant access using a single user account
  • Secure storage of tenant credentials using strong cryptographic encryption
  • Server hardening and enhanced access control
  • Improved tenant isolation while maintaining centralized management

Impact

The new architecture removed previous tenant limitations, strengthened security, simplified user management, and created a scalable foundation capable of supporting future enterprise growth.

Performance

High-Performance Pagination with Intelligent Redis Caching

03

Challenge

Users experienced noticeable delays when navigating large datasets because every page request triggered a new database query.

Solution

I designed a predictive caching strategy using Redis. Instead of caching only the current page, the system intelligently preloaded the previous, current, and next page.

  • Predictive preloading of previous, current, and next pages
  • Cached results served instantly whenever available
  • Background services continuously refreshing surrounding pages
  • Automated cache invalidation to remove unused Redis keys
  • Efficient memory usage without compromising data consistency

Impact

The solution dramatically reduced database load, minimized response times during pagination, and delivered a significantly smoother user experience for large datasets without compromising data consistency.

Portfolio

Featured Projects

Cloud platforms, developer tools and production websites - built end to end, from architecture and APIs to the interface people actually use.

TecnnoVault screenshot
Featured2
Cloud Apps•Architect & Developer

TecnnoVault

A two-tier cryptographic data vault that replaced credential sharing over chat. Shelves and pages organise team knowledge while secrets sit behind envelope encryption, tiered access and full audit trails.

Next.jsNestJSPostgreSQLEnvelope EncryptionRBAC
PLH Connect screenshot
Featured
Cloud Apps•Lead Engineer

PLH Connect

A multi-tenant travel agency CRM covering leads, bookings, itineraries, quotations, invoices and payments - with per-tenant databases, centralised identity and Redis-backed pagination for large datasets.

Next.jsNestJSMulti-tenancyRedisRBAC
Live Site
Tecnnovates Management Portal screenshot
Featured
Cloud Apps•Lead Engineer

Tecnnovates Management Portal

The internal admin platform behind the company site - contact request triage, testimonial collection and publishing, and career postings, all from a single role-aware dashboard.

Next.jsREST APIDashboard UIRole-based Access
Cloud Apps
Cloud Apps•Associated

Optiomax

A commercial optimisation platform I contributed to as part of the engineering team, working across application features and delivery.

Web PlatformTeam Delivery
Live Site
Cloud Apps
Cloud Apps•Final Year Project · UOM

Pharmacy Information System

medFind.lk - a pharmacy information system connecting patients with nearby pharmacies, covering medicine availability, stock management and pharmacy administration.

LaravelPHPMySQLBootstrap
Source Code
Cloud Apps
Cloud Apps•Associated

TGL Management App

A business management application built with the team, covering day-to-day operational workflows and internal reporting.

Web PlatformTeam Delivery
Private / client project
Academics

Education & Certifications

The academic grounding behind the engineering -from primary school in Badulla to a BIT from the University of Moratuwa.

University of Moratuwa

Degree

Bachelor of Information Technology, Computer Software Engineering

Dec 2020 – Jun 2024

Graduated with a degree in Bachelor of Information Technology, specializing in cutting-edge software development and research.

Conducted in-depth research on multi-tenancy architecture, exploring efficient methods for scalable application design and implementation. As part of my academic project, I developed a comprehensive platform to streamline the management of pharmacies enabling users to find medicines efficiently while incorporating the latest technologies for inventory management and real-time updates.

This experience enhanced my skills in full-stack development, cloud computing, and database optimization, laying a strong foundation for solving real-world challenges with innovative solutions.

Skills: Back-End Web Development, Software Deployment, +17 skills

University of Moratuwa

Full Stack Developer in Python, Information Technology

Jun 2022 – Dec 2022

Completed a Full Stack Developer course covering Python, HTML, CSS, JavaScript, web application development, cloud application fundamentals, data security, databases, APIs, version control, and software development best practices.

Built practical projects while gaining hands-on experience in developing secure, scalable, and responsive web applications using modern development tools and technologies.

Kandegedara Central School

GCE Advanced Level - Technology Stream

2015 – 2018

Completed the GCE Advanced Level in the Technology Stream, building a strong foundation in Engineering Technology, Information and Communication Technology (ICT), problem-solving, analytical thinking, and technical concepts that prepared me for higher studies and a career in software engineering.

Uva College, Badulla

Primary & Secondary Education - GCE Ordinary Level

Jan 2004 – Dec 2015

Completed my primary and secondary education at this school, studying from Primary Grade through the GCE Ordinary Level (O/L). This period provided a strong academic foundation while fostering discipline, teamwork, leadership, and personal growth through both academic and extracurricular activities.

Licenses & Certifications

Formal training that backs the day-to-day engineering work.

Bachelor of Information Technology

University of Moratuwa

Issued Jan 2024

AWS Essentials: A Complete Beginner's Guide

Udemy

Issued Dec 2025

UC-5bff5904-fa46-4c04-95d4-994900966e3c

Server-Side Web Programming

University of Moratuwa

Issued Jan 2024

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Front-End Web Development

University of Moratuwa

Issued Dec 2023

Front-End_Web_Development_E-Certificate

Web Design For Beginners

University of Moratuwa

Issued Nov 2022

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Python for Beginners

University of Moratuwa

Issued Sep 2022

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Get In Touch

Have a project in mind or want to collaborate? I'd love to hear from you. Let's create something amazing together.

Let's start a conversation

I'm always interested in new opportunities, whether it's a full-time position, freelance project, or just a chat about technology and innovation.

Quick Response

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