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Hello, my name is

Samuel Santos.
FullStack Developer

1.About Me

As a Full Stack Engineer, I have extensive experience working with various technologies and tools, from back-end to front-end, to ensure comprehensive and integrated solutions for my clients. Additionally, I have strong skills in web application development, data processing automation, and mobile app projects.

Among the technologies I master are NodeJS, ReactJS, and React Native, which I use to build robust and scalable applications. I also have skills in databases, including MySQL, MongoDB, and PostgreSQL, and in API integrations to ensure communication between systems. I'm passionate about learning new technologies and always looking for new opportunities to learn and grow.

When I'm not coding, I like to spend my time watching anime, playing games like Valorant, The Witcher 3, and sometimes League of Legends and reading books on economics and the history of ancient societies...

Picture of me

2.Technologies I Use

Programming Languages

JavaScript (ES6+)

Web scripting language

TypeScript

Typed JavaScript superset

Python

Programming language

HTML5

Markup language standard

CSS3

Cascading style sheets

JavaScript Libraries & Frameworks

React.js

JavaScript library

Next.js (13+)

React.js framework

Node.js

JavaScript runtime environment

Express.js

Node.js framework

NEST.js

Node.js framework

CSS Tools & Frameworks

Tailwind CSS

CSS framework

Bootstrap

CSS framework

Material UI

React UI library

Chackra-ui

React UI library

Databases & Back-end Services

MongoDB

NoSQL database

PostgreSQL

SQL database

Firebase

Google BaaS

MySQL

SQL database

ClickHouse

High-performance columnar database

AI Integrations

OpenAI

AI-powered language models

Qdrant

Vector similarity search database

Development Tools

Docker

Containerization platform

3.Experience

  1. Company

    Sizebay - Software Engineer

    Core Responsibilities:

  2. Architected an event-driven data platform ('data_events') using AWS SQS, NestJS micro-services, and ClickHouse, enabling ingestion of >15 million events/day with end-to-end processing latency under 30 seconds.

  3. Refactored the legacy order & return workflow into streaming micro-services (Node.js, RxJS, NestJS), allowing the export of 1 million+ records in < 10 minutes (previous system routinely timed-out) and delivering automated e-mail notifications upon completion.

  4. Developed AI-powered recommendation services that generate 'similar' and 'complementary' product suggestions via OpenAI embeddings + Qdrant vector search, boosting product click-through.

  5. Built a self-service analytics layer on top of ClickHouse, exposing custom reports through a REST API; this reduced ad-hoc reporting requests.

  6. Authored & published an internal NPM library that auto-generates README files, semantic versions, and changelogs; integrated GitHub Actions CI/CD to cut release times from hours to minutes and standardize documentation across four teams.
  • Company

    Gargantua Technologies - Software Engineer

    Core responsibilities & achievements:

  • Architected and delivered a multi-tenant, role-based REST API (80+ endpoints, OAS 3.0) with NestJS and TypeORM, covering authentication, customer onboarding, loans, approvals, refinancing, payments, branch finance, routing logistics and BaaS webhooks.

  • Applied SOLID principles and common design patterns (Factory, Strategy, Repository) to modularize services, enforce clean architecture and enhance code maintainability and testability.

  • Containerized all backend services using Docker (including Docker Compose for local development), ensuring consistent environments across dev and test.

  • Implemented robust asynchronous messaging with RabbitMQ, including fallback handlers, dead-letter queues and retry policies to guarantee reliable event processing under failure.
  • Company

    TOTVS - Full Stack Engineer

    Core responsibilities & achievements:

  • Full-stack development of web applications using Node.js (backend) and React.js (frontend), continuously enhancing performance and user experience.

  • Legacy system modernization: Fixed critical bugs in PHP codebases to improve stability, then migrated complex reporting modules to Node.js microservices—halving report generation times.

  • Design system contributions: Led the creation and integration of new React components, ensuring seamless adoption within the existing UI library and maintaining visual consistency.

  • Codebase refactoring: Streamlined legacy code across both back and front ends, applying SOLID principles and design patterns to boost maintainability and reduce technical debt.

  • Team leadership: Guided development of new modules and components, coordinating reviews and knowledge sharing to uphold best practices and smooth feature delivery.

    • 6.Some Projects I've Built

    Featured Project

    My Manga Recap
    Comprehensive AI-powered system featuring adaptive providers (OpenAI, Local, Silent) with automatic fallback, advanced OCR using multiple engines (GPT-4o Vision, TrOCR, Tesseract), specialized script templates for different manga scenes, and optimized batch processing capable of handling multiple chapters in parallel with real-time progress monitoring.
    PythonOpenAIOCRAIVideo Generation
    My Manga Recap

    Featured Project

    eGestor2Printer
    Browser extension designed for e-commerce efficiency, automatically extracting order information from web pages and generating standardized fiscal receipts. Features company configuration management, seamless integration with existing order systems, and one-click printing functionality to streamline business operations.
    JavaScriptChrome ExtensionsHTMLCSS
    eGestor2Printer

    Featured Project

    Constru.rapi
    A comprehensive clone of Twitter, with a familiar interface and a range of essential features such as profiles, tweets & replies, followings, likes & retweets, notifications and direct messaging system and, more.
    ReactTypeScriptGraphQLMYSQLMaterial UIReact NativeDevopsDigital OCean
    Constru.rapi

    Featured Project

    Notify-me-aws
    Notify-me is a project developed with the purpose of keeping track of the release of new chapters of manga I read. As the release depends on independent translations from Korean/Japanese to English/Portuguese, sometimes it takes weeks until a new chapter is released. The program uses Scrapping to extract information from different sites in search of the latest release of the saved mangas in a database (DynamoDB) and will notify me through a Telegram bot.
    JavascriptPuppeteerTelegram APIAWS LambdaAmazon EventBridgeDynamoDBServerless Framework
    Notify-me-aws

    Featured Project

    E-motion
    The e-motion is an application created to facilitate monitoring and interaction between psychologists and clients. In it, it is possible to make emotional records of situations experienced by the client: what feelings are involved, contexts, causes, and consequences. All records can be accessed by the psychologist responsible for the client. The psychologist can have access to all the emotional records of their patients and, consequently, make a closer follow-up.
    ExpoReact NativeNode.jsExpress.jsRedux
    E-motion

    Featured Project

    Athena labs
    Athena is a project based on Cardano that aims to be a reliable platform and focused on rewards for trading goods and services
    JavaScriptChakra-uiReactVercel
    Athena labs

    5.What's Next?

    Get In Touch

    Have a question or want to work together?

    Connect with me via social media or send me an e-mail.