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Available for freelance projects & collaborations

Hello, I’m

Ranga
Rathnayake

Senior Full Stack Engineer, Software Architect, Microservices Specialist, Web3 & Blockchain Developer, Cloud & DevOps Engineer

I architect and ship end-to-end products — from a BNPL fintech platform serving 50,000+ users to real-time delivery systems running at 99.9% uptime. 8+ years across fintech, Web3, logistics and government.

View my workDownload CV
Portrait of Ranga Rathnayake, Senior Full Stack Engineer & Software Architect

Ranga Rathnayake

Full Stack · Architect

8+ yrs

01About me

Engineering products end-to-end, from idea to production.

I’m a results-driven Senior Full Stack Engineer and Software Architect with 8+ years of experience across fintech, Web3, government and food delivery. I take products the whole way — requirement gathering, system design, backend, web, mobile, CI/CD and production support.

My sweet spot is microservices, real-time systems and payments: NestJS services that scale, WebSocket-powered live tracking, and payment flows that don’t fail. I care about clean architecture, measurable outcomes and shipping on time — every time.

Based in

Colombo, Sri Lanka

Currently

Senior Full Stack Engineer

Education

Software Engineering · Java Institute

Languages

English · Sinhala

8+

Years of experience

20+

Clients delivered end-to-end

50K+

Fintech users served

99.9%

Production uptime

02Experience

8+ years of shipping real products for real users.

From government systems to fintech at scale — every role has been about owning outcomes end-to-end.

  1. Senior Full Stack Engineer

    Rockland Distilleries (Pvt) Ltd·Narahenpita, Colombo 5

    — Present

    Architecting and building the ‘Ting’ food delivery platform from the ground up — from requirements to production.

    • Architected NestJS microservices with a Next.js frontend, owning the full lifecycle from analysis and system design to deployment.
    • Engineered real-time GPS tracking and GIS-based location search over WebSockets to coordinate riders, customers and restaurants.
    • Built Azure DevOps CI/CD pipelines and automated releases, cutting deployment time by 60%.
    • Keep production at 99.9% uptime for thousands of daily transactions; integrated payment gateways, SMS and mapping APIs.
    • NestJS
    • Next.js
    • Microservices
    • WebSockets
    • GIS/GPS
    • Azure DevOps

  2. Senior Full Stack Engineer

    Payzy·Papiliyana, Nugegoda

    —

    Led end-to-end development of a Buy Now Pay Later fintech platform serving 50,000+ users.

    • Designed a NestJS microservices architecture built for scalability and reliability of financial workloads.
    • Modelled ACID-compliant schemas for secure payment processing and data integrity.
    • Integrated multiple payment gateways with fallbacks — 99.5% transaction success on millions in monthly volume.
    • Shipped React Native apps to Play Store & App Store (4.5★+), SSR web apps in Next.js, and Azure Functions that cut infra costs by 40%.
    • NestJS
    • React Native
    • Next.js
    • React
    • Azure Functions
    • PostgreSQL

  3. Software Engineer

    Wayamba Development Authority·Kurunegala

    —

    Built management and tax-collection systems for government projects, improving operational efficiency by 70%.

    • Worked directly with municipal councils and pradeshiya sabhas to gather requirements and deploy across multiple jurisdictions.
    • Developed Java SE/EE desktop applications and Android apps for field data collection, digitising manual processes.
    • Designed friendly interfaces for non-technical staff, ran training sessions and provided ongoing support.
    • Java SE
    • Java EE
    • Android
    • MySQL

  4. Associate Software Engineer

    Techno Action·Kurunegala

    —

    Delivered enterprise Java solutions across multiple client projects and industries.

    • Contributed across the full SDLC — requirements, development, deployment and maintenance.
    • Learned industry best practices and modern methodologies alongside senior engineers.
    • Java
    • Enterprise Apps
    • SDLC

  5. Independent Contractor & Freelance Developer

    Self-employed·Remote

    — Present

    End-to-end development specialist for 20+ clients — with a 100% delivery rate and 95% client satisfaction.

    • Own the whole lifecycle: requirements, system analysis, architecture, database design, web/mobile/backend, CI/CD, servers and maintenance.
    • Use AI-assisted workflows to ship 50% faster while keeping code quality high.
    • Long-term retainers and referrals built on consistent, on-time delivery.
    • Full Stack
    • Web3
    • Fintech
    • DevOps
    • AI-assisted dev

03Selected work

Products I’ve architected & built.

A selection of platforms I’ve designed and delivered — measured by the outcomes they drive.

Real-time · Logistics

Ting — Food Delivery Platform

A food delivery ecosystem built from scratch: NestJS microservices, a Next.js frontend, live rider tracking and GIS-powered location search, with payments, SMS and maps integrated end-to-end.

Uptime
99.9%
Deploy time
−60%
  • NestJS
  • Next.js
  • WebSockets
  • GIS/GPS
  • Azure DevOps

Fintech · Payments

Payzy — BNPL Fintech Platform

A Buy Now Pay Later platform with microservices, ACID-safe financial data, multi-gateway payments with automatic fallbacks, and native mobile apps on both stores.

Users
50K+
Txn success
99.5%
Infra cost
−40%
  • NestJS
  • React Native
  • Next.js
  • Azure Functions

E-commerce · Architecture

Sithuwari — Batik & Fashion Store

Currently architecting and developing the online store for Sithuwari, a premium handcrafted batik and fashion label for men, women and kids.

In production
Live
  • System Architecture
  • E-commerce
  • Full Stack
Visit sithuwari.lk(opens in a new tab)

More projects & platforms

  • GovTech

    +70%Efficiency

    Government Tax & Management Systems

    Management and tax-collection software for municipal councils and pradeshiya sabhas, with Android apps for field data collection.

    • Java EE
    • Android
    • Desktop

  • Growth · Analytics

    100K+Referral txns

    Referral Marketing Platforms

    Complete referral systems with multi-tier commissions, user dashboards and real-time analytics.

    • Node.js
    • Real-time
    • Dashboards

  • Network Marketing

    10K+Members

    MLM Platforms — Binary & Unilevel

    Complex compensation plans, genealogy trees, e-wallets and automated commission calculations.

    • Node.js
    • E-wallet
    • Automation

  • Web3 · Blockchain

    On-chainSmart contracts

    Web3 dApps & NFT Marketplace

    Decentralised apps with smart contract integration, crypto payments, NFT marketplaces and wallet connectivity.

    • Solidity
    • Web3
    • Smart Contracts

  • Finance · SaaS

    End-to-endDelivery

    Financial Management Suite

    Accounting, invoicing, expense tracking and financial reporting dashboards for growing businesses.

    • Full Stack
    • Reporting
    • PostgreSQL

  • Open Source · IoT

    TCPRaw packets

    GPS Tracker Backend

    A Node.js TCP server that ingests and parses raw SinoTrack ST-901 / H02 GPS packets, shipped as a Docker image on GHCR.

    • Node.js
    • TCP
    • Docker
    • GHCR
    View on GitHub(opens in a new tab)

04What I do

How I can help your team.

Whether you need a whole product built or a senior engineer to own a critical system, I bring architecture and hands-on delivery together.

  • Full-Stack Product Engineering

    From requirement gathering to launch — architecture, backend, web and mobile, all shipped and maintained by one accountable engineer.

  • Microservices & System Architecture

    Scalable, observable NestJS microservices and data models designed to grow with your users.

  • Fintech & Payments

    BNPL, wallets and payment gateway integrations with fallbacks, ACID guarantees and security in mind.

  • Real-time & Geo Systems

    WebSocket-driven live tracking, GIS search and dispatch flows for logistics and delivery.

  • Cross-platform Mobile Apps

    React Native apps shipped to the Play Store and App Store with 4.5★+ ratings.

  • Web3 & Blockchain

    dApps, smart contracts, NFT marketplaces and crypto payments with wallet connectivity.

  • Cloud & DevOps

    Azure DevOps and Docker/Kubernetes pipelines, serverless functions and zero-drama releases.

  • AI-Enhanced Delivery

    AI-assisted workflows and local LLM exploration to move 50% faster without cutting corners.

05Tech stack

The tools I use to build at scale.

A pragmatic, production-proven stack across frontend, backend, mobile, cloud and Web3. Drag the sphere to explore.

Languages

  • TypeScript
  • JavaScript
  • Java
  • Go
  • Python
  • Solidity

Frontend & Mobile

  • React
  • Next.js
  • Angular
  • React Native

Backend & APIs

  • Node.js
  • NestJS
  • Express.js
  • REST
  • GraphQL
  • WebSockets

Cloud & DevOps

  • Azure DevOps
  • Azure Functions
  • AWS
  • Docker
  • Kubernetes
  • CI/CD
  • Nginx
  • Linux
  • Git

Databases

  • PostgreSQL
  • MySQL
  • MongoDB
  • Redis

Architecture & Specialised

  • Microservices
  • Web3
  • Smart Contracts
  • Real-time GIS/GPS
  • Local LLMs

06Contact

Let’s build something great together.

Have a product idea, a system that needs an architect, or a role to fill? My inbox is open — I usually reply within a day or two.

Email me at

hello@rangarathnayake.com

Colombo, Sri Lanka · Working with teams worldwide

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