Fer Guerrero

Backend Developer

Jan 2025 - Apr 2026 • 1 yr 3 mos

Worked at Anti-Corruption & Good Governance Secretariat - System Architecture: Architected and built from scratch a microservices-based complaint management system handling 2,162 citizen complaints (∼180/month), using Java 17, Spring Boot 3.2, and deployed on AWS (ECS, S3, RDS). - Cloud Migration: Led the migration of a legacy on-premise system to AWS, eliminating firewall-blocked data access, broken email services, and routing failures that impacted 300+ government users. - CI/CD Automation: Drove deployment time down by 83% (30 min →5 min) by owning the design of CI/CD pipelines with Jenkins and Maven, including automated builds, tests, and quality gates. - AI Integration & Async Processing: Owned the integration of AI-driven complaint summarization by connecting a Spring Boot microservice with an external Python API, implementing asynchronous processing with Spring Batch to maintain system responsiveness under load. - Security: Implemented government-compliant security using Spring Security with JWT, role-based access control, and API key validation. - Database Optimization: Improved query performance by 60% by redesigning PostgreSQL and SQL Server schemas and tuning Hibernate / Spring Data JPA queries.

Fullstack Developer

Aug 2024 - Nov 2025 • 1 yr 3 mos

Worked at Webdecero - Enterprise Intranet Development: Contributed to the development of a corporate intranet platform using PHP and Laravel, implementing modules for employee management, internal operations, and business workflows. - SAP Integration & Marketplace: Developed a procurement marketplace integrated with SAP, enabling employees to browse products, create purchase requests, and synchronize order information with enterprise resource planning processes. - Learning Management System (LMS): Built and maintained training and course management modules, supporting content delivery, employee enrollment, progress tracking, and certification workflows. - Biometric Access Control System: Developed backend services and AI-powered biometric solutions for access control kiosks and turnstiles, combining facial recognition and fingerprint verification technologies. - Computer Vision & AI: Implemented biometric identification features using Python, OpenCV, and machine learning models to improve authentication accuracy and automate user verification processes. - API & Database Development: Designed REST APIs, business logic, and database structures while collaborating with cross-functional teams to deliver production-ready enterprise solutions.

Backend Developer

Aug 2024 - Dec 2024 • 4 mos

Worked at Nextline (Bap Corporativo) - Financial Transaction Logic: Built core backend logic for a consumer fintech platform, including withdrawal requests, fund validation, state transitions, and audit trail, ensuring data integrity across financial operations using Node.js and MySQL. - Real-Time Currency Conversion: Developed currency conversion functionality by integrating external exchange rate APIs and implementing caching strategies to reduce latency and handle real-time calculations at scale. - Database Optimization: Refactored and optimized MySQL schema to support new business logic for clients, transactions, and investments; improved query performance through indexing and entity relationship design. - Request Lifecycle Management: Implemented full request lifecycle for user refunds and withdrawals, covering validation, pagination, filtering, status transitions, user notifications, and audit logging.