Gabriel Castillo
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About

Backend engineer with 3+ years of remote experience building REST APIs, integrations and internal tools with Python/Django, NestJS, Laravel and Java, now applying that background to BI and data analytics.

Pixel-art portrait of Gabriel Castillo

I like the difficult part of a system: following a record, message or transaction through SQL, logs and code until the failure is clear, then turning the finding into a fix the team can maintain.

At Keyrus I designed and built an internal Django application that analyzes files and estimates effort for the team. Before that I worked on SWIFT messaging, electronic invoicing and a regional benefits platform.

Download the CV

  • Spanish · native
  • English · B2
  • Tunja, Colombia · Remote

Experience

  1. BI and Data Analytics Intern

    Keyrus Colombia

    Jul. 2026 – Present
    • Designed and built an internal Django application that analyzes files and estimates effort for the team.
    • Built its REST API with DRF, background processing with Celery and Redis and PostgreSQL persistence, with automated tests in GitHub Actions.
    • Prepared and validated data with SQL and Python for dashboard analysis.

  2. Freelance Full Stack Developer

    TotalDev SAS

    Feb. 2025 – Mar. 2026
    • Added SWIFT MT support to an interbank gateway in Java/Apache Camel: MT103 and MT202 validation and automated ISO 20022 conversion.
    • Developed the core modules of an electoral inventory platform in Laravel and React: bulk imports with row-level validation, regional permissions, Excel reports and queued PDF generation.
    • Built a QR-scanning PWA for the operators of an industrial plant and its Laravel/Filament backend, with approvals, PDF delivery notes and monthly inventory reports.

  3. Full Stack Developer

    PARQ

    Nov. 2024 – Jul. 2025
    • Extended the SATCOM, Siigo and Alegra electronic invoicing connectors in a Laravel middleware with queued resend of failed invoices and per-request tracing.
    • Maintained the NestJS and PostgreSQL services of a parking platform in Colombia, Mexico and the UK: country-specific rates, queued bulk membership creation and consistent timezones in reports.
    • Built the corporate Next.js site with SSR, i18n and SEO and documented the APIs with OpenAPI.

  4. Backend Developer

    SEREMPRE

    Jan. 2023 – Nov. 2024
    • Diagnosed L2/L3 production incidents by tracing each failure through SQL, code review and Sentry, and documented its root cause.
    • Built Laravel APIs for a benefits platform in more than five Latin American countries, with queues for validated payment uploads, duplicate cleanup and notifications.
    • Wrote queries, PL/SQL procedures and Excel exports for other teams, and containerized legacy systems with Docker/DDEV.

Skills

Languages

  • Python
  • TypeScript
  • PHP
  • Java
  • SQL

Backend

  • Django
  • DRF
  • Celery
  • NestJS
  • Laravel
  • Filament
  • Apache Camel
  • REST
  • OpenAPI

Data

  • PostgreSQL
  • MySQL
  • Oracle PL/SQL
  • Redis
  • pandas
  • Excel
  • Power BI
  • Tableau

Operations

  • L2/L3 diagnosis
  • Sentry
  • Docker
  • Portainer
  • GitHub Actions
  • Linux

Education

Expected 2026

Bachelor of Engineering in Systems and Computer Engineering

Universidad Pedagógica y Tecnológica de Colombia (UPTC), Tunja

2022

Technologist in Information Systems Analysis and Development

Servicio Nacional de Aprendizaje (SENA), Tunja