Jemelito Constantino

Portfolio

Jemelito Constantino

@jemelitoconstantino · Purok 6, Brgy. Cagniog, Surigao City, Philipppines

Senior Fullstack Engineer with 10 years of experience building production-grade applications from the ground up. Expertise in web platforms, blockchain systems, crypto trading infrastructure, and high-performance APIs. Proven track record delivering end-to-end solutions in finance, NFT gaming, cryptocurrency, and multi-chain trading.

Experience

  • Senior Fullstack Developer

    ArrowFin · Chicago, IL

    https://arrowfin.io/

    Mar 2025 - Jan 2026

    Role

    • •Senior Fullstack Developer

    Challenges & achievements

    • 1.ArrowPoint Web Application
    • -Built the MVC infrastructure in the frontend using Next.js routes and Zustand.
    • -Worked on a responsive UI and provided a dynamic layout with dark and light themes.
    • -Implemented a WebSocket client for live trading data and integrated the Fintatech chart into the React interface for live charting.
    • -Used dynamic forms for user input to extract UIs from JSON and added full validation with Zod.
    • 2.Mock Server
    • -Built a Node.js Express project to mock trading data without real API calls for development mode.
    • -Implemented RESTful APIs and a WebSocket server based on the Rithmic API, and designed the logic for generating live price and transaction data.
    • -Used Docker to deploy and share the mock server with teammates.
    • 3.Backend
    • -Built a Spring Boot project from the ground up and implemented RESTful APIs in Java.
    • -Integrated various APIs, including the Rithmic API and a PostgreSQL database.
    • -Provided a WebSocket server to broadcast live trade data to the frontend

    Skills

    • React
    • Java
    • Node.js
    • TypeScript
    • TailwindCSS
    • Material UI

Education

  • Bs in Computer Science

    Surigao Del Norte State University

    Jun 2009 - Jan 2013

    Siargao, Philipppines