SF Samuel Ferreira

Software Developer ยท Systems Analysis and Development

Business software, back-end services, and practical web products.

I build applications around real workflows: authenticated APIs, relational data, transaction-safe business rules, responsive interfaces, automation, and tests that make the behavior reviewable.

FastAPI layered APIs and role-based access
PostgreSQL migrations, transactions, and concurrency
React responsive interfaces and dashboards
Go services, queues, and resilient workflows
Testing unit, integration, and boundary cases

About

Learning software engineering by building complete systems.

I am completing a degree in Systems Analysis and Development. My portfolio is where I apply subjects such as software architecture, databases, networks, operating systems, requirements, and secure development.

I prefer projects with clear domain rules and visible trade-offs. The documentation separates implemented behavior, local validation, and future production work so that each claim can be checked against the code.

Technical focus

Tools used across the portfolio.

Back-end development

Python, FastAPI, Go, Node.js, REST APIs, authentication, authorization, validation, and background workers.

Data and consistency

PostgreSQL, SQLite, SQLAlchemy, Alembic, schema design, transactions, idempotency, and concurrency control.

Front-end development

React, TypeScript, JavaScript, HTML, CSS, responsive layouts, forms, dashboards, and API integration.

Quality and delivery

Pytest, Go tests, integration tests, GitHub Actions, Docker, Compose, technical writing, and reproducible setup.

Security fundamentals

Least privilege, password hashing, secret management, input validation, encrypted fields, and audit trails.

Additional experience

Automation, Discord integrations, commercial websites, Unreal Engine, Unity, and user-facing product communication.

Selected projects

Work that can be reviewed and discussed.

01

ZirphasOS repair management

A FastAPI and PostgreSQL system for repair intake, estimates, inventory, payments, customer tracking, and controlled order transitions.

PythonFastAPIPostgreSQLDocker
Open repository
02

React business dashboard

A responsive dashboard with derived metrics, category comparisons, stock alerts, and project progress.

ReactJavaScriptViteCSS
View project
03

Discord support ticket bot

A Node.js integration with slash commands, private ticket channels, staff permissions, logs, and interactive components.

Node.jsDiscord.jsAPIsDocker
View project
04

Market automation CLI

A Python and SQLite application for product records, inventory changes, sales, reports, and automated tests.

PythonSQLiteCLITests
View project
05

Interactive movement systems

Prototype work for vehicle movement, animation, and interactive simulation in Unreal Engine and Unity.

Unreal EngineUnityC++Lua
View project
06

Rental website

A responsive site for a Brazilian apartment rental business, with unit filters, structured information, and a WhatsApp inquiry flow.

HTMLCSSJavaScriptResponsive UI
View case study

Engineering approach

Clear scope, reproducible setup, honest validation.

Repository documentation explains how to run each project, which checks were completed, and which production concerns remain. Localized applications retain Portuguese interfaces when that matches their intended users.

Browse the catalog

Contact

Open to software development opportunities.

For roles, internships, or project discussions, contact me through LinkedIn.