Hello I'm Rafael Jonathan!
Software Engineer with 5+ years of experience specializing in front-end development using libraries or frameworks like React.JS and Next.JS with back-end development skills in Node.JS, Express.JS, and Python.
Experience working with AI/LLM projects. Skilled in building responsive web applications and delivering technical solutions that create business value.
Work Experience
About the Company
Datasaur is a leading company in both NLP labeling platforms and LLM projects.
Software Development Engineer
I work on both front-end and back-end development for their Large Language Model (LLM) project squad, contributing to the development of Datasaur Large Language Model (LLM) solutions in model comparison, model prompt answering, model knowledge base / document management, model evaluation, and model fine-tuning. My role involves implementing new features, optimizing performance, and ensuring seamless integration between front-end and back-end systems, some of the contributions that I’ve made are:
- Collaborated on and delivered AI consultation projects with Datasaur clients to assist them in integrating Large Language Models (LLMs) into their business operations. Key contributions include:
- Managed AI consultation projects with clients, by delivering various AI solutions that brought in $300k in revenue across 9+ successful projects.
- Built and delivered Q&A chatbot solution that processes 5,000+ documents, for easier legal document questions and answers.
- Contributed to the development of AI agents for assessing document and data risk levels.
- Developed Chatosaur Slack chatbot from scratch, helping teams work more efficiently with automated responses and conversation summaries powered by LLM.
- Pioneered in the early development of LLM solutions as part of Datasaur's new product line, aiming to generalize the use of LLM in the AI space.
About the Company
Tokopedia is one of the largest e-commerce companies in Indonesia. Tokopedia is a subsidiary of a new holding company called GoTo and Tokopedia is one of Indonesia's unicorn companies.
Software Engineer - Web Platform
I specialized in front-end development, focusing on building responsive and performant user interfaces for customer resolution systems. I worked extensively with React.JS and TypeScript to create intuitive help center interfaces and real-time chat solutions that connected users with customer service teams. My involvements includes:
- Collaborated with cross-functional teams to develop internal dashboard tools, resulting in 1 billion IDR cost savings by not using third-party applications.
- Completely rewrote the Self Service Chatbot module, refactoring old legacy code, standardized architecture that works across different pages. The result is reduced time in development and delivery up to 5 times.
- Develop new projects for feature improvements such as the Resolution/Complaint Handling Page, Help Article Page, Chatbot Page, and other Internal Websites. These enhancements improve customer experience by aiding easy navigation and issue resolution in Tokopedia.
About the Company
BliBli is one of the largest e-commerce companies in Indonesia. Blibli provides the most complete omnichannel commerce platform and lifestyle ecosystem in Indonesia.
Mobile Developer Intern
I contributed to maintaining and developing their e-commerce Android application mainly in payment modules. My primary responsibilities included:
- Built and maintained payment features for checkout, making sure transactions went smoothly.
- Set up WebView content management, making content delivery and user engagement better.
- Worked with CMS to handle content preview functionality, improving content management workflow.
Front-end Development
Work as a self-employed and part-time front-end developer, specializing in creating user-friendly web applications. Skilled in responsive design and seamless user interactions to deliver high-quality digital solutions.
- Built responsive web apps for various internal projects or landing pages focused on enhancing user experience and functionality.
- Create web projects for building landing pages for a company's profile.
About the Company
Bina Nusantara University is one of the largest universities in Indonesia. Bina Nusantara focused on providing quality education and research in the field of technology and business.
Database Administrator
I was responsible for managing academic data systems and infrastructure. My key responsibilities included:
- Maintained and optimized student attendance tracking systems.
- Processed and analyzed laboratory competency assessment data.
- Administered internal web applications and database servers for academic data management.
Laboratory Instructor
I teach hands on lab studies of computer science topics like object-oriented programming, database, and web development.
- Teaching various hands on lab studies of computer science topics.
- Research development on topics of game development, desktop and business analysis, web programming, mobile programming, and network programming.
Projects

Chatosaur
A powerful Slack chatbot powered by Large Language Models (LLM) that helps teams boost their productivity.

Occupedia
A project for GarudaHack hackathon submission, Occupedia helps people meet their dream job by simplifying the recruitment process, from applying to jobs, aptitude testing, meeting interviews and live coding interviews that are all provided by Occupedia.

Suryanesia
A freelance web project to help build Suryanesia landing page for their company, the web was built using Next.JS with google sheet integrated for their contact us form.

Import Partner
A freelance web project to help build Import Partner's website to handle the company shipping transactions and help users track their orders, the web was built using Next.JS.

HINO Part Catalog
A freelance web project to help build Hino's website to organize their products categorization and image tagging for their specific spare parts catalog using javascript canvas, the web was built using React.JS.
Certifications

Meta Front-End Developer
Earned after finishing 9 courses about Front-End Development using HTML, CSS, JavaScript, React, and Node.js from Meta Front-End Developer.

IBM Full Stack Software Developer
Earned after finishing 10 courses about Full Stack Development using HTML, CSS, JavaScript, Node.js, React, and MongoDB from IBM Full Stack Software Developer.

Architecting with Google Compute Engine Specialization
Earned after finishing 5 courses about managing cloud development infrastructure and functionality on GCP from Architecting with Google Compute Engine Specialization.

Cloud Application Development Foundations
Earned after finishing 4 courses on introduction to cloud computing, web development and cloud development in NodeJS & ReactJS from Cloud Application Development Foundations.

Winner of BEST ECONOMIC OPPORTUNITY PROJECT - Occupedia
Garuda Hacks 2.0 is a global 36-hour virtual hackathon where the world's greatest talents will compete to solve the world's most pressing challenges using technology.
About me

I'm Rafael Jonathan Patrick Tjoa
I'm a software engineer who's always been fascinated by the world of web development, and learning something new always excites me to improve and help others with the skills I gain. I specialize in front-end development using libraries/frameworks like React.JS and Next.js with general knowledge of back-end development. I have 5+ years of experience working on front-end development and successfully delivering and maintaining products so they could scale up to new requirements and improvements.