Guilherme

Castro

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Backend .NET
| Fullstack
Developer

Experience

I specialize in .NET 8 and Angular 20, focused on scalable systems using Clean Architecture, DDD and CQRS. In production since 2024, I helped raise NPS from -30 to +100 on a mission-critical system.

2025

Viceri SEIDOR

Software Analyst Trainee — present

I directly contributed to the architectural design and ground-up development of a mission-critical system, replacing a legacy .NET/SQL ecosystem. Launched in 2025 with NPS +100 (previously -30 on the legacy system).

I implemented Event-Driven Architecture with RabbitMQ and MassTransit, applied DDD, CQRS and Clean Architecture, and built modular components with Angular 20 and Micro-frontends.

  • .NET 8
  • C#
  • Angular 20
  • PostgreSQL
  • RabbitMQ
  • Redis
  • Docker
  • Azure DevOps
2024

Viceri SEIDOR — Mapfre Team

Legacy Systems Modernization

I designed and implemented a CRM access audit solution with full traceability of sensitive data. I led the update of HTTP security header rules, mitigating client-server communication vulnerabilities.

I maintained applications on AWS and IIS, optimized queries and provided operational support on MySQL.

  • Classic ASP
  • MySQL
  • IIS
  • AWS
Peep em pé

Education

Solid academic background in System Analysis and Development and selected for 42 São Paulo, a peer-to-peer software engineering school with a new common core focused on applied AI, RAG and Python.

  • Software Engineering

    42 São Paulo

    Starting: May 2026 — peer-to-peer methodology, common core with Python, applied AI and RAG
  • Tech Degree

    System Analysis and Development

    Universidade Descomplica — Jan 2024 – Jun 2026 (in progress)

Certifications

  • 2025–2026 - Balta.io, .NET Specialist
  • 2023–2024 - Origamid, Frontend Training (HTML, CSS, JS)

Edu
ca
tion

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