Hernie J

Full Stack Developer

Sandlot • Freelance

Sep 2025 - Jan 2026 • 4 mos

At Sandlot, I served as the primary developer for Holdtones, a social media application designed to connect users both locally and globally. I developed the mobile application using FlutterFlow and native Flutter, incorporating complex real-time features like audio/video calls, international messaging, and a "Vicinity" user discovery system that connects people nearby. On the backend, I built and maintained the server using Node.js, Express, and Supabase to ensure reliable data handling. Beyond coding, I managed the product lifecycle using Linear for task tracking and GitHub for version control, conducting weekly sync meetings to align with goals. My role was truly end-to-end, covering everything from initial mobile development to the final deployment on Android and iOS.

Senior Developer

Cerebrox Information Technology • Full-time

Jun 2023 - Sep 2025 • 2 yrs 3 mos

At CerebroxIT, I served as a Senior Developer on the Smart School System project, a comprehensive platform deployed across multiple colleges and basic education institutions in the Philippines. I led the web development using CodeIgniter to handle core academic functions like enrollment, grading, and staff management. To bridge the digital and physical campus, I engineered tapping stations using Raspberry Pi and RFID scanners installed at gates, cafeterias, worship halls, and stores—enabling student identification, attendance tracking, and cashless payments. I also developed a React Native mobile app that gave students and parents access to academic info and a loading system for funds. Additionally, I built an SMS Gateway using GSM modules and Raspberry Pi to push real-time notifications for attendance, payments, and announcements, ensuring seamless communication across the school community.

Frontend Developer

Product Marketing Alliance (PMA) • Part-time

Mar 2023 - Jul 2023 • 4 mos

At Product Marketing Alliance (PMA), I contributed to the enhancement of their content platform built on Ghost CMS. Using React.js and Tailwind CSS, I developed new frontend features that improved how users interacted with marketing resources and publications. I worked closely with the backend team to integrate APIs, ensuring that data flowed smoothly between the server and the user interface. Beyond feature development, I took ownership of performance optimization, implementing techniques like code splitting and lazy loading to reduce load times and improve Core Web Vitals. I also ensured that every component was fully responsive, delivering a consistent and accessible experience whether users were on desktop, tablet, or mobile devices.