Software Engineer Based in Sri Lanka

I'm Sandaruwan Jayasundara, a Senior Software Engineer and AI Engineer based in Sri Lanka. Since July 2024 I have worked remotely as a Senior Software Engineer at Decryptogen LLC, a US company, where I lead the design and development of web applications built with React, Next.js, Node.js, Spring Boot, and Python, along with AI features built on OpenAI, LangChain, and FAISS. Before that I worked at Mobitel and Wenthura Solutions in Colombo.

Key takeaways

• Current role: Senior Software Engineer at Decryptogen LLC (United States), full-time and remote, July 2024 – present.
• Career path: Trainee, then Associate Software Engineer at Wenthura Solutions (2021–2023), Software Engineer at Mobitel (2023–2024), then Decryptogen.
• Education: BSc (Hons) in Information Technology, specializing in Software Engineering, from SLIIT (2019–2023).
• Focus: full-stack web applications, Java/Spring Boot and Node.js backends, cloud deployment on AWS, and applied AI (RAG, text-to-SQL).
• Working model: remote collaboration with international teams across time zones, from UTC+5:30.

Background and Education

My formal training started at the National Institute of Business Management (NIBM), where I completed a certificate in Computer Software Engineering (2017–2018). I then studied for a BSc (Hons) in Information Technology, specializing in Software Engineering, at the Sri Lanka Institute of Information Technology (SLIIT) from 2019 to 2023. My first industry role began in late 2021, so the last part of my degree overlapped with full-time engineering work.

Alongside the degree I have completed several certifications, mostly in cloud and AI:

• AWS Certified Cloud Practitioner (2025), plus AWS Cloud Essentials and AWS for Games (2023)
• ChatGPT Prompt Engineering for Developers and LangChain for LLM Application Development, both from DeepLearning.AI (2023)
• Convolutional Neural Networks (Coursera / DeepLearning.AI, 2022) and Computer Vision Mobile Applications (CV Zone, 2022)
• Foundations of User Experience (UX) Design (Google, 2022)

Career Path

My career has moved from general web development, through large enterprise and telecom systems, to leading product and AI work for a US company. In order:

Wenthura Solutions (2021–2023)

I joined Wenthura Solutions as an intern and trainee, learning Java, Express.js, Node.js, and professional development workflows while contributing to frontend and backend code. After promotion to Associate Software Engineer I worked in the R&D team on healthcare-focused platforms, including a medical software project for clients based in Sweden.

Mobitel (2023–2024)

At Mobitel, a mobile telecommunications operator, I did full-stack work on large-scale enterprise and telecommunications applications using Java, Spring Boot, Apache Kafka, React, TypeScript, and Angular, with Oracle DB and Informix DB on the data side, Jenkins and Docker for delivery, and deployments on Microsoft Azure. Projects included:

• A reporting system with a data analytics and reporting dashboard
• The Mobitel mConnect web application
• An inventory management system and the Upahara package management system
• An automated SMS delivery platform for new SIM card purchases and network activations
• Internal tools and API development

Decryptogen LLC (2024–present)

At Decryptogen I lead the design and development of scalable web applications using React, Next.js, React SSR, Spring Boot, Node.js, and Python, with Docker and Jenkins for DevOps, AWS for hosting, and both MongoDB and PostgreSQL for data. A growing part of the role is AI development with OpenAI, LangChain, and FAISS. The work is done with international teams, fully remote.

What I Work On Now

Most of my current work falls into two groups. The first is product engineering: full-stack applications such as an HR management system covering the full employee lifecycle, a centralized admin portal, and a Next.js rebuild of the company website. The second is applied AI: retrieval-augmented generation (RAG) chat systems and text-to-SQL pipelines that need to give correct answers, not just plausible ones.

If you want detail on how I approach either area, see my notes on building production RAG systems with LangChain and on backend architecture best practices.

My Specialization as a Software Engineer

• Backend architecture and API design (REST, GraphQL) with Spring Boot and Node.js
• Full-stack web applications with React, Next.js, and TypeScript
• Cloud-native deployment on AWS, with Docker and CI/CD pipelines
• Relational and document database design (PostgreSQL, MySQL, Oracle, MongoDB)
• LLM features: RAG, prompt engineering, and schema-constrained text-to-SQL

Software engineering is not just writing code — it is designing systems that scale, adapt, and remain maintainable for years.

Tech Stack

Full Stack Development Approach

Modern software engineering requires understanding both frontend and backend ecosystems. Owning a feature from the database schema to the UI, and through to deployment, removes handoffs and makes trade-offs visible early. That is why I work across the stack rather than in a single layer.

Working with International Clients Remotely

My working time zone is Sri Lanka Standard Time (UTC+5:30), which has no daylight saving changes. In practice that gives the following overlaps with a normal working day:

• UK and Europe: my afternoon overlaps their morning, so same-day discussion is straightforward.
• Australia and New Zealand: my morning overlaps their afternoon.
• United States: my evening overlaps the US East Coast morning (for example, 8:00 a.m. EST is 6:30 p.m. in Colombo), and the time difference means work can progress while the US team is offline.

Remote work with a large time difference depends more on process than on hours online. The practices I rely on:

• A fixed, agreed overlap window for meetings, reviews, and decisions
• Written updates and decisions recorded in tickets and pull requests, so nobody waits for a call to get context
• Small, reviewable pull requests and CI/CD pipelines, so changes can be checked asynchronously
• Containerized, documented environments so anyone on the team can run and deploy the code

For a wider look at how this works from a hiring perspective, see hiring a remote software engineer for a startup, or read about the local IT industry and its developers.

Selected Projects

• Aiden – AI Chat Assistance (lead developer): a RAG-based chat application with document Q&A, conversation memory, and multi-model support, built with React, Node.js, LangChain, OpenAI, FAISS, PostgreSQL, and AWS.
• Audience Craft AI (AI engineer): a text-to-SQL system that turns a campaign brief into an audience segment, then launches campaigns on Meta, TikTok, and Google. Read the Audience Craft AI case study.
• ATS AI (AI engineer): an applicant tracking system that parses and ranks CVs, schedules interviews, assigns tasks, and exposes its matching engine through an API. Read the ATS AI case study.
• HR System (senior developer): employee lifecycle, attendance, leave, and performance tracking with Java, Spring Boot, PostgreSQL, React, and AWS.
• Equipment Rental System and Gear Genie (full-stack developer): rental and e-commerce platforms with inventory, booking, payments, and order tracking on React, Node.js, Express, and MongoDB.

The full list is on the projects page.

Building for Global Standards

Location does not decide how well a system runs. CI/CD pipelines, containerization, automated testing, and observability are what let a system serve users worldwide, wherever its engineers sit.

Final Thoughts

My focus is on scalable architectures, secure systems, and code that stays maintainable after launch, and more and more on AI features that hold up in production. If you are looking for a remote engineer for full-stack, backend, or AI work, my full-stack development services and about page cover how I work.

Frequently Asked Questions

Who is Sandaruwan Jayasundara?

Sandaruwan Jayasundara is a Senior Software Engineer and AI Engineer based in Sri Lanka. He has worked as a Senior Software Engineer at Decryptogen LLC, a US company, since July 2024, building full-stack web applications, backends, and AI features.

Which time zone does he work in?

He works in Sri Lanka Standard Time (UTC+5:30), which has no daylight saving changes. His afternoon overlaps the UK and European morning, his morning overlaps Australian afternoons, and his evening overlaps the US East Coast morning.

Where has he worked?

In order: Wenthura Solutions as Trainee and then Associate Software Engineer (Nov 2021 to Mar 2023), Mobitel as Software Engineer (Apr 2023 to Jul 2024), and Decryptogen LLC as Senior Software Engineer (Jul 2024 to present).

What is his educational background?

He holds a BSc (Hons) in Information Technology, specializing in Software Engineering, from SLIIT (2019 to 2023), and earlier completed a certificate in Computer Software Engineering at NIBM (2017 to 2018). He is also an AWS Certified Cloud Practitioner.

What technologies does he specialize in?

React, Next.js and TypeScript on the frontend; Java, Spring Boot, Node.js, Express and Python on the backend; PostgreSQL, MySQL, MongoDB and Oracle for data; AWS, Docker and Jenkins for deployment; and OpenAI, LangChain and FAISS for AI features.

Does he work with international clients?

Yes. His current role is remote work for a US company with international teams, and earlier he worked on a medical software project for Sweden-based clients. Project enquiries can be sent through the contact page on sandaruwan.dev.

I'm Sandaruwan Jayasundara — Senior Software Engineer | Full Stack Developer. Explore more technical articles at sandaruwan.dev or get in touch.