Justin Sheen Guiriba

Experience

Where I've worked.

  1. November 2025 — June 2026

    Backend Developer | Team Lead · Impulse101 IT Solutions

    Full-time

    • Led backend development for a mobile product with 50,000+ downloads on Google Play, designing scalable RESTful APIs that reduced average response time and improved the user experience.
    • Designed and managed relational and NoSQL database schemas to streamline data access patterns, reducing query latency while supporting Kubernetes deployments and CI/CD pipeline automation that significantly cut deployment time.
    • Strengthened application reliability through DNS management, virtual machine operations, and log-based alerting, achieving 99%+ uptime and faster incident detection in production.
    • Collaborated with cross-functional teams to gather requirements and ensure seamless integration of web and mobile services, driving project completion ahead of schedule.
    CloudCI/CD AutomationAPIFlutterMongoDB

  2. June 2025 — July 2026

    Backend Developer · 1TEQ Providers

    Internship

    • Shipped a C# and Avalonia UI desktop application integrating the client's external API for real-time POS transaction processing, storing transaction records in MySQL to eliminate manual reconciliation and improve cashier throughput.
    • Built a full Point of Sale system and, upon early completion, extended it into a Purchase Order management system using PHP, HTML, CSS, and JavaScript — delivering two functional systems within the same OJT period.
    • Replaced the company's reliance on third-party developers by independently building all required internal tools from scratch, reducing external costs and giving the team full ownership of their software.
    C#APIC# AvaloniaSQL

  3. November 2024 — May 2025

    QA Tester · Fulcrum

    Part-time

    • Executed end-to-end test suites using Cypress and Cucumber, identifying and documenting critical defects across multiple sprint cycles and preventing regressions from reaching production.
    JavaScriptCypressCucumber

  4. 2024 — 2026

    Full-Stack, IoT & AI Engineer · Independent Freelancer

    Freelance

    • Integrated LLM APIs (OpenAI GPT, Google Gemini) into client applications, designing custom prompt-engineering pipelines and context-aware AI workflows that automated content generation and intelligent query handling.
    • Delivered end-to-end IoT solutions, including an RFID-enabled vending system and an AI-powered aquarium monitoring system that reads and interprets pH and water-quality sensor data via LLM integration, eliminating manual tracking for both clients.
    • Built full-stack web applications with Python, Django, Flask, and React — covering UI, backend APIs, and database architecture — with on-time delivery and zero post-launch critical bugs across all engagements.
    • Collaborated closely with clients to understand requirements and deliver tailored solutions, resulting in high satisfaction and repeat business.
    ClaudeGeminiOpenAIPythonDjangoFlaskReact