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> Hi, I'm

Guillermo Castillo

Systems Engineer · Full Stack Developer

I build complete web applications with React, .NET, Django and Laravel, and I automate data processes with ETL, Airflow and Power BI.

Buga, Valle del Cauca, Colombia

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01 · about

Software that improves productivity

I am a Systems Engineer with more than 8 years of experience developing web applications. I use frameworks like Django, .NET Core and Laravel for the backend, and ReactJS for the frontend. I have good knowledge of data processing and analysis, I work with ETL tools and I use Power BI for data visualization.

I communicate well, I like working in a team and I adapt quickly to changes. I face complex problems with a focus on solving them and finding new ideas, and I build efficient solutions that improve productivity.

  • 8+years of experience
  • 5companies
  • ~70%less time in automated processes
  • B2English level

02 · experience

Work experience

  1. Senior Developer

    Siesa

    2026 – Present
    • Development of two platforms with AI assistance.
    • AI agent management platform: the user creates an agent, adds knowledge to it and gives it more capabilities with page tools and MCP tools.
    • Customer data management platform: the user connects data sources and creates reports with the help of an AI agent.
    • React
    • .NET 10
    • PostgreSQL
    • Docker
    • Cube
    • MCP

  2. Technical Consultant

    Kata Software S.A.S

    2025 – 2026
    • I built a middleware service layer to connect Kata Mobile, Kata Engine and external systems of clients in the financial sector.
    • Integrations with credit bureaus, identity validation services and electronic signature services.
    • Sending and receiving information from the internal systems of the clients.
    • Creation of PDF documents for electronic signature and reports, and basic image processing.
    • Deployment on Azure App Services, using Azure Storage for files and Application Insights for monitoring and logs.
    • .NET 8
    • C#
    • Azure App Services
    • Azure Storage
    • Application Insights

  3. Senior Full Stack Developer

    Mawesi S.A.S

    2018 – 2024
    • Support and improvements for the web application that manages requests in a university.
    • Optimization of the Production System web application for a pharmaceutical company, with data loading using DataStage and reports in Power BI and Excel.
    • Modules to load and transform data with Pandas inside a Django application, automating manual processes and reducing the time by about 70%.
    • Migration of data processing solutions to Apache Airflow, improving scalability and maintenance.
    • ETL processes in DataStage from many sources to different destinations, scheduled or on demand.
    • Automated workflow with Jenkins to run tests and SonarQube to check code quality continuously, improving the development standards before delivery to the client.
    • React
    • Laravel
    • PostgreSQL
    • .NET Framework
    • Oracle
    • Django
    • Pandas
    • Airflow
    • DataStage
    • Power BI
    • Jenkins
    • SonarQube

  4. Development Engineer

    Opal Group S.A.S

    2017 – 2018
    • Implementation of the CRM system for new clients with Django, Oracle and MySQL, and AngularJS for the interface.
    • Project management module: registration and calculation of operating and administrative costs for a construction company.
    • Configurable packages module to group services and supplies in a hierarchy, with a ReactJS interface.
    • Python
    • Django
    • Oracle
    • MySQL
    • AngularJS
    • React

  5. Intern

    Nuevos Medios S.A.S

    2015 – 2016
    • Diagnosis and solution of issues in the KME e-learning platform, improving its stability and performance.
    • Integration with Zoom video calls and configuration of AWS CloudFront for video streaming.
    • Visual update of the platform, moving from jQuery and Bootstrap to AngularJS with Material Design.
    • Development of the interoperability module with the LTI standard as my degree project.
    • AngularJS
    • Material Design
    • AWS CloudFront
    • Zoom API
    • LTI

03 · projects

Personal projects

  • MSI Performance Manager

    Performance manager for MSI gaming laptops that works with Wayland: live sensor monitoring, profiles, GPU power limit and Cooler Boost, using Polkit for privileges.

    • Rust
    • Tauri 2
    • Preact
    • Linux

  • HtmlToPdfDotNet

    Library to create PDFs from HTML directly in .NET.

    • C#
    • .NET 10
    • PDF

  • DRRR

    Web chat inspired by the Dollars group from the Durarara!! series, deployed on Firebase.

    • TypeScript
    • Firebase

  • Music Player

    Desktop music player for Windows, macOS and Linux.

    • TypeScript
    • Electron
    • React

  • Kata .NET Project

    Solution for the technical test of Kata Software, built with .NET.

    • C#
    • .NET
See more on GitHub

04 · skills

Tech stack

Languages

  • Python
  • JavaScript
  • TypeScript
  • C#
  • PHP

Frameworks & libraries

  • Django
  • React
  • .NET Core
  • Laravel
  • Node.js

Databases

  • Oracle
  • PostgreSQL
  • SQL Server
  • MySQL

Data processing

  • DataStage
  • Pandas
  • NumPy
  • Apache Airflow
  • Cube

Cloud, DevOps & BI

  • Azure
  • AWS CloudFront
  • Docker
  • Jenkins
  • SonarQube
  • Power BI

Artificial intelligence

  • AI agents
  • MCP

05 · education

Education and certifications

  • 2017

    Degree

    Systems Engineering

    Universidad del Valle

  • 2025

    Certification

    IBM Full Stack Software Developer Certificate

    IBM · Coursera

  • 2025

    Languages

    English course (B2 intermediate)

    English Now

  • 2023

    Course

    Power BI Data Analysis Course

    Platzi

  • 2015

    Course

    Cloud Services Development with HTML5, JavaScript and Node.js

    Miriadax

  • 2015

    Course

    Software Testing Techniques

    Universidad del Valle

06 · contact

Let's build something together

Do you have a project or a proposal, or do you just want to talk? Write to me and I will answer as soon as possible.

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