Back-end
- C#
- .NET 8 / .NET Core
- ASP.NET Core
- Entity Framework
- Node.js
- Express
- REST APIs
Belo Horizonte, Brazil (UTC−3)
Vítor Henrique
Santos Reis
Full Stack Developer · C# · .NET Core · React.js
6+ years building scalable, high-performance web applications, focused on complex system integrations, tax and invoicing platforms, and automation of business-critical processes.
- Invoices issued, no manual step
- ~3,000 / month
- Vehicles in production
- ~10,000
- Manual review with OCR
- 1 week → hours
01 — About
Professional summary
I'm a Full Stack Developer with over 6 years of experience building scalable, high-performance web applications. I work primarily with C#, .NET Core and Entity Framework, with a strong track record in integrating complex systems.
I move with equal depth between two ecosystems: C# / .NET with Angular and Blazor, and Node.js with React. On top of that, Python automation, relational and non-relational databases, and deep expertise in compliance-heavy billing — invoices filed with government tax authorities and payment slips issued through bank APIs.
Today I act as the technical reference for a development team: running code reviews, supporting architecture decisions and mentoring developers early in their careers.
- End-to-end billingFrom contract to bank payment slip and filed tax invoice, no manual step
- Invoicing at volume~3,000 tax invoices filed per month, with headroom to spare
- Automation & OCRA week of manual checking per month cut down to a few hours
- Legacy modernizationMigrating VB6 systems and automating manual processes
- Technical leadershipCode review, engineering standards and team mentoring
02 — Stack
Technologies and skills
The tools I work with day to day, from the back end through to production.
Front-end
- React.js
- Angular
- Blazor
- TypeScript
- JavaScript
- Tailwind CSS
Integrations
- E-invoicing (tax authorities)
- Bank APIs (payment slips)
- Third-party APIs
- RabbitMQ
- SignalR
Python & automation
- Python
- FastAPI
- OCR (Tesseract)
- OpenCV
Data
- SQL Server
- PostgreSQL
- MongoDB
- Data modeling
Infrastructure
- Docker
- Linux
- AWS (EC2)
- IIS
- Windows Services
- Quartz (job scheduling)
- Serilog
- Swagger / OpenAPI
Architecture & quality
- Clean Architecture
- DDD
- Microservices
- SOLID
- Testing with xUnit
- Code review
Practices
- Git
- Scrum / Kanban
- Technical mentoring
- Requirements gathering
Legacy
- VB6
- Crystal Reports
- Migration to .NET
03 — Career
Work experience
- Oct 2025 — Present
Software Development Consultant
Head5 Engenharia·Direct hire since Apr 2026 · started via Tarso Tecnologia·Belo Horizonte, Brazil·Hybrid
- The team's only senior developer, acting as technical reference for one junior developer and two interns: code review, architecture decisions and mentoring.
- Built the OCR document reader in Python, replacing the manual checking of technical PDFs — around a week of work per month cut down to a few hours of review.
- Deployed the OCR service on an Ubuntu server and the .NET applications on IIS on the company's own server.
- Designing new features as microservices, with domain-driven modeling (DDD) and REST APIs between them.
- Unit and integration tests with xUnit on critical modules, checked during code review.
- Analyzing, specifying and implementing custom enterprise solutions.
- Continuously improving internal development processes.
- Aug 2025 — Oct 2025
Systems Analyst
Siematec Informática
- Maintained and evolved a deep-legacy VB6 system with Crystal Reports, including interoperability with newer modules written in C#.
- Built integrations between the legacy system and modern platforms, prioritizing scalability and reliability.
- Migrated features to newer technologies and automated previously manual processes.
- Modeled the new C# modules with DDD, isolated from the legacy code as independent services.
- Automated tests with xUnit on the new modules, creating a safety net for the gradual migration.
- Supported the technical team in requirements analysis and production troubleshooting.
- Jan 2024 — Aug 2025
Full Stack Developer
Globalrv Rastreamento Ltda·sgtrack.com.br
- Built the company's automated billing pipeline: the system reads each contract and the fleet attached to it, issues the payment slip through the bank's API and files the tax invoice with the Belo Horizonte tax authority — one flow, no manual step.
- Around 3,000 tax invoices filed per month in internal use, with the pipeline sized well above that.
- Integrated the APIs of three banks (Inter, Itaú and Bradesco) to issue and track payment slips.
- Maintained and evolved the freight (CT-e OS) and invoicing systems in C#, .NET Core and Entity Framework, keeping compliance intact through every rule change from the tax authority.
- Split the system into independent services using DDD, isolating the billing, fleet and tax-filing domains.
- Unit and integration tests with xUnit on the tax and banking routines, where a production failure means an invoice filed wrong.
- Mar 2020 — Jan 2024
Full Stack Developer
Freelance
- Delivered web solutions for clients across several industries, focused on robust and scalable applications.
- Built a balance-lookup platform for the Brazilian severance fund (FGTS), unifying four third-party APIs.
- Created a service with advanced financial data lookup features.
- Hosted and maintained the applications on AWS EC2 instances: provisioning, deployment and monitoring.
- Developed company websites applying front-end and back-end best practices.
04 — Projects
Selected work
Solutions I built and kept running in production, with real users.
OCR document reader
Head5 EngenhariaA system that reads technical PDF documents on its own — including scanned pages, which to a computer are nothing but photos. It locates the tables inside the file, recognizes the text and returns the data already structured. Checking that used to consume about a week per month, page by page, now runs in minutes and comes down to a few hours of review.
SGTrack
Fleet tracking platform covering roughly 10,000 vehicles, with automated billing: it reads the contracts, issues the payment slip through the bank's API and files the tax invoice with the authority in a single flow.
Consulta Saque
Balance-lookup platform for the Brazilian severance fund (FGTS), unifying four third-party APIs into a single flow with failover between providers.
API FGTS
Service exposing advanced financial data lookup features, designed to be consumed by other applications.
GN Engenharia
Company website built from scratch, focused on performance, responsiveness and front-end and back-end best practices.
05 — Education
Education and courses
B.Sc. in Information Systems
Centro Universitário Newton Paiva·since Jun 2025
Computing fundamentals, logic and algorithms, data structures, computer architecture, databases and software engineering, with emphasis on object-oriented programming.
Technical degree in Web Development
FATEC SENAI Belo Horizonte·on hold
HTML, CSS, JavaScript, React.js, Node.js and both relational and non-relational databases, with hands-on projects run in agile methodologies (Scrum and Kanban).
Online courses
Alura
- Entity Framework Core
- .NET Core
- Bootstrap 4
Udemy
- React + Redux
- Modern Web 2022
- OOP in Java
06 — Contact
Let's talk
I'm open to new opportunities, projects and technical conversations — including remote roles with international teams. I'm based in Brazil (UTC−3), which overlaps with most US and European working hours. Pick whichever channel you prefer; I usually reply quickly.