Enterprise Software Developer
.NET, SQL Server, Angular & Legacy System Modernization
I help businesses modernize legacy applications, automate operations, and build secure internal systems that are easier to maintain, scale, and support.
Services
Practical solutions built on deep enterprise experience
Legacy System Modernization
Migration of older ASP.NET Web Forms, VB.NET, and .NET Framework applications into modern .NET with cleaner architecture, improved maintainability, and long-term support readiness.
Internal Business Applications
Custom business tools for orders, inventory, reporting, operations, and workflow management—built to match your team's actual processes and scale with your business.
API & System Integration
REST API design and integration with third-party services including FedEx/UPS carrier APIs, SFTP file workflows, BizTalk-related processes, and internal enterprise systems.
SQL Server & Reporting
Stored procedure development, query performance tuning, data grids, import/export workflows, business data processing, and enterprise reporting solutions built for real-world scale.
Automation & File Processing
SSIS packages, Windows scheduled tasks, WinSCP/SFTP file automation, operational logging, alert systems, and data pipeline automation to reduce manual effort and increase reliability.
Architecture & Documentation
Technical documentation, system diagrams, Jira ticket specifications, Confluence pages, and developer-driven documentation to support teams and future maintainability.
Skills
Deep Microsoft-stack experience across the full enterprise development lifecycle
Backend
Frontend
Database
DevOps / Hosting
Integrations
Tools & Workflow
Experience
A track record of delivering real solutions in enterprise environments
Senior Enterprise Developer
Senior enterprise developer focused on Microsoft technologies, building and maintaining mission-critical business applications using .NET, SQL Server, Angular, and related tooling across the full development lifecycle.
Legacy ASP.NET Modernization
Extensive experience maintaining and modernizing legacy ASP.NET Web Forms and VB.NET applications—migrating functionality to modern .NET without disrupting live business operations.
API Design & Internal Tools
Designed and implemented RESTful APIs and internal business tools for enterprise operations, including carrier integrations, order management, and operational dashboards used daily by business teams.
SQL Server & Data Systems
Deep experience with SQL Server-heavy systems, stored procedure-based architectures, data modeling, query performance optimization, and supporting large enterprise datasets with real-time reporting requirements.
Reporting, Workflows & Automation
Improved reporting screens, upload workflows, file processing pipelines, and automated operational tasks to reduce manual effort, cut processing time, and increase system reliability across enterprise environments.
Architecture & Team Support
Created technical architecture documentation, system flow diagrams, Jira specifications, and Confluence pages to help teams understand complex workflows, plan future development, and onboard new developers effectively.
Projects
Real enterprise solutions that deliver measurable business value
RSOMS Modernization
Modernization of a Retail Solution Order Management System from legacy .NET Framework and VB.NET toward modern .NET, C#, cleaner architecture, API-based communication, improved UI, structured logging, and long-term maintainability.
FedEx / UPS Return Label Automation
Automated return label generation using internal APIs, carrier account validation, OAuth authentication, file processing, SQL Server storage, and operational logging with full error tracking and retry support.
Enterprise Reporting Optimization
Improved large report workflows using SQL Server stored procedures, optimized data loading with server-side paging and filtering, export options, and a cleaner report UI design that dramatically reduced load times.
SFTP File Monitoring & Alerts
Automated SFTP tracking file monitoring using WinSCP logs, PowerShell alerts, SSIS integration, timestamped logging, and support notifications for full operational visibility into file delivery status.
SQL Server Database Comparison Tool
Tool to compare a source and target SQL Server database and generate a synchronization script that brings the target up to date with the source — keeping schema, stored procedures, tables, and constraints consistent across multiple clients running the same application version.
Enterprise Operations Dashboard
Transformed large, hard-to-read datasets into a clear and actionable operations dashboard with KPI cards, summary charts, drill-down filters, and export capabilities — giving business users immediate visibility into the metrics that matter most.
About
Eddy Castillo is a software developer focused on solving real business problems through practical architecture, clean implementation, and strong database knowledge. His strength is understanding how legacy enterprise systems work, improving them without breaking business operations, and creating solutions that support teams, users, and long-term maintainability.
Modernization is not only about new technology. It is about making systems easier to support, safer to change, and better for the business.
Contact
Have a project in mind? Let's talk about what we can build together.
Connect with me