Hello, I'm Juan Trilnardo Defrin

Founder & Fullstack Engineer | Next.js | Node.js | AWS

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Profile photo of Juan Trilnardo Defrin

About Me

AI-Augmented Fullstack Developer and Cloud/Backend Engineer with 3+ years of experience delivering production web applications across the insurance, mining, and MSME sectors.

Founder of a digital agency (Kastemin), I lead a cross-functional team of 5 people spanning development, UI/UX design, branding, content, and marketing — guiding projects from concept to launch. I engineered a Web GIS platform from scratch on Next.js and AWS serverless architecture, cutting database query times from 60 seconds to 3 seconds, and integrated an autonomous AI coding agent (OpenClaw) into my daily workflow to accelerate release cycles.

Bandung, Indonesia
jtdefrin33@gmail.com
Bachelor's in Computer Science

Education

September 2020 - September 2024
Bachelor's degree of Computer Science
Bina Nusantara University
GPA: 3.8/4.0
  • Relevant Coursework: Algorithm and Programming, Data Structures, Software Engineer, Mobile Object-Oriented Programming, Artificial Intelligence, Program Design Methods, Human and Computer Interaction, Database Systems, Computer Networks, Algorithm Design and Analysis
2017 - 2020
Science Major
SMAK BPK Penabur Holis
  • Getting 9th place for the City Science Olympiad event - (Computer) 2019

Experience

IT Officer
January 2026 - Present
PT Asuransi Raksa Pratikara
Engineered and maintain Raksa Terrafix, a Web GIS platform for insurance operations, built from scratch on Next.js and AWS serverless architecture.
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Founder & Fullstack Engineer
September 2025 - Present
Kastemin
Founded and manage a digital agency building custom web applications and digital solutions for MSMEs (UMKM).
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Staff Programmer (Fullstack Developer)
July 2024 - October 2025
PT Jadin Pratama
Developed and maintained web applications using PHP with frameworks including CodeIgniter 3 (MVC) and Laravel.
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Application Developer (Internship Student)
February 2023 - February 2024
PT Freeport Indonesia
Work Full Home (Remote) using AlpacaJS and Internal Framework to create forms for underground mining operations.
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Shipping Tracking System
2 Month
Developed a desktop application using Electron.js to streamline and secure the shipping receipt (resi) process in offline warehouse environments.
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Helpdesk - Tech Monitoring
3 Month
Developed an automated chat response system to immediately follow up on customer reports, improving transparency and customer trust.
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Helpdesk - Support Monitoring
3 Month
Developed an app that tracks support team performance and speeds up issue resolution. It automatically follows up on customer reports, boosting transparency and trust. This helps reduce complaints and ensures quicker response times, improving SLA compliance.
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Iroly Fishing - POS System & Admin Dashboard
1 Month
Developed a unified solution for Iroly Fishing, combining a Point-of-Sale (POS) system for managing customer purchases, inventory, and sales, along with an admin dashboard to provide analytics on sales performance, stock levels, and business insights in real-time.
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Kastemin - Client Web Portal
2 Month
Developed a secure and user-friendly client portal for Kastemin, allowing clients to track project progress, view reports, communicate directly with the team, and share documents in real-time for better project collaboration.
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Wedding Invitation - Customizable Digital Invitations
1 Month
Developed a platform where couples can create and personalize their digital wedding invitations. The platform includes a variety of customizable templates, options for text and images, and easy sharing capabilities through email and social media.
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Raksa Terrafix - Insurance Web GIS & Risk Simulation Platform
Ongoing
Built Raksa Terrafix from scratch — a Web GIS platform for insurance risk operations, featuring interactive hazard-map visualization, spatial grid analytics, and a scenario simulation engine with real-time budget-impact analysis.
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LifePharm - AI Customer Service Bot
Ongoing
Built a WhatsApp AI customer service bot that answers customer questions automatically, and hands the conversation off to a live human agent whenever the question falls outside what it knows.
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Skills

Frontend Development
  • HTML5
  • CSS
  • JavaScript
  • Next.js
  • TypeScript
  • jQuery
  • AlpacaJS
  • Responsive Web Design
Backend Development
  • Node.js
  • Express.js
  • PHP
  • CodeIgniter 3
  • Laravel
  • C#
  • .NET Framework
Database
  • MySQL
  • PostgreSQL
  • SQL Server
  • Stored Procedures
Cloud & DevOps
  • AWS Lambda
  • API Gateway
  • Amazon S3
  • Amazon RDS (PostgreSQL)
  • Microsoft Azure
  • Azure Functions
  • Deployment Management
GIS & Geospatial
  • Web GIS
  • GeoJSON
  • Leaflet
  • Geospatial Data Processing
AI & Developer Productivity
  • AI-Assisted Development (OpenClaw)
  • Developer Productivity Engineering
Mobile Development
  • Flutter
  • Java
Other Skills
  • Communication
  • Requirement Analysis
  • Quality Assurance
  • Team Leadership

Contact Me

Bandung, Indonesia
jtdefrin33@gmail.com
linkedin.com/in/juantdefrin
github.com/juantdefrin94