João Queiroz, Developer in Lisbon, Portugal
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João Queiroz

Verified Expert  in Engineering

Full-stack Developer

Lisbon, Portugal

Toptal member since November 11, 2022

Bio

João is a software engineer with a solid experience in both back-end and front-end development. His main area of expertise is working in Express.js, Node.js, and React, and his background includes diverse projects, from smart homes to energy and cybersecurity. João is a diligent worker, always bringing excellence and contributing to good team cooperation, leaving clean code and good practices for other developers.

Portfolio

HydraDev
React, JavaScript, TypeScript, Express.js, Node.js, MongoDB
Loop OS
Next.js, React, TypeScript, Front-end
FRS Systems
React Native, Jest, TypeScript, Mobile

Experience

  • Express.js - 5 years
  • Node.js - 5 years
  • JavaScript - 5 years
  • TypeScript - 5 years
  • Python 3 - 4 years
  • React - 4 years
  • SQL - 4 years
  • MongoDB - 3 years

Availability

Part-time

Preferred Environment

TypeScript, JavaScript, Node.js, Express.js, React, Python 3

The most amazing...

...app I've developed is a smart home app that allows users to control and monitor their caravans in real time remotely.

Work Experience

Full-stack Developer

2022 - PRESENT
HydraDev
  • Built a platform to manage company operations, including employee management, HR recruitment funnel, and client management.
  • Worked on a real estate platform that scrapes from different sources daily and allows users to find the best properties.
  • Created a platform for the Portuguese government to manage projects and filter them by different specifications.
  • Worked on a stock market project to allow users to analyze and filter by different indicators. This involved scraping as well.
Technologies: React, JavaScript, TypeScript, Express.js, Node.js, MongoDB

Front-end Developer

2024 - 2024
Loop OS
  • Developed a circular business management app using Next.js and React.
  • Integrated multiple applications to streamline circular business operations.
  • Led a major refactor to significantly enhance code quality and maintainability.
  • Implemented numerous advanced features to optimize functionality.
Technologies: Next.js, React, TypeScript, Front-end

Mobile Developer

2023 - 2024
FRS Systems
  • Developed a React Native app in TypeScript for cruise line ticket management.
  • Integrated physical device functionalities, including keys, QR code, and infrared reader.
  • Conducted thorough testing to ensure reliability and performance.
Technologies: React Native, Jest, TypeScript, Mobile

Back-end Developer

2023 - 2023
Pelmorex
  • Worked as a back-end developer for a 50+ million user weather app using a clean architecture with Node.js, Python, and Redis for the database.
  • Improved by 10x the speed of a time-critical task involving 500,000 requests with multi-processing techniques.
  • Developed complex business logic for two codebases (Python and Node.js) and connected them with the help of Amazon SQS, S3, and Lambda.
  • Followed a test-driven development (TDD) approach, consistently with over 80% code coverage.
  • Collaborated within an Agile Scrum environment, regularly conducting code reviews and fostering strong teamwork for efficient project delivery.
Technologies: Node.js, TypeScript, RxJS, Amazon Simple Queue Service (SQS), MQTT, Python, Amazon S3 (AWS S3), Docker, Jest, AWS Lambda, Jenkins, Redis, AWS IoT, Amazon Web Services (AWS)

Back-end Developer

2022 - 2022
Imaginary Cloud
  • Worked as a back-end developer on a cybersecurity platform using Python, Flask, Docker, MongoDB, and Ansible.
  • Built a bot in Python for a strategy decentralized finance (DeFi) game, performing Web3 transactions.
  • Implemented a back end capable of managing and starting multiple machines simultaneously using Ansible.
Technologies: Python 3, Flask, Ansible, Docker, MongoDB

Software Engineer

2019 - 2022
AKKA Benelux
  • Developed a smart caravan app allowing users to control and monitor their caravan from anywhere, including controlling lights, air conditioning, speed, and getting location.
  • Built an app for Volkswagen for reporting and managing internal issues.
  • Worked on a desktop app for visual testing using computer vision, which was used by top car makers and manufacturing companies, such as Stihl and BMW.
Technologies: JavaScript, Node.js, Express.js, Python 3, C++

Experience

Collaboration Management Tool: A Full-stack Application for Streamlining Teamwork

Developed a full-stack application using Next.js, React, TypeScript, TailwindCSS, and Node.js to enable seamless collaboration among team members. The app facilitates project management by providing the ability to add, assign, and track tasks among team members. Additionally, the app allows team management by assigning roles, adding new team members, and monitoring their progress. Overall, the app aims to increase efficiency and streamline teamwork.

Project Management Government App

An app that allows entities of the Portuguese government to add technical information related to projects and its buildings. Multiple filters can be used, similar to Power BI. I worked as a full-stack developer responsible for building most of the API and implementing tables, maps, and filters in the front end.

HR and Company Operations Platform

A platform to manage every company-related information, including employee information and holidays, HR funnel, or potential clients. I worked as a full-stack developer and developed multiple features, including displaying company events and achievements, displaying and managing employee information, cron jobs, and Slack notifications.

Real Estate Platform

A real estate platform that empowers users to make informed decisions through seamless search functionality and dynamic data visualization. I worked as a full-stack developer with React, ExpressJS, TypeScript, and MongoDB.

Smart Caravan App

A smart home app applied to caravans, enabling users to monitor and control them. I was a full-stack developer, working on the front end and creating a progressive web app (PWA) to make it mobile and desktop friendly. Furthermore, I worked on the back end, allowing for real-time communication with caravan devices, such as lights and air conditioning, and allowing users to control these devices in real time.

Volkswagen Issues Platform

An internal app for Volkswagen that allows managing internal issues and automatically emailing the responsible people about them. I worked on the back end, dealing with all the application programming interface (API) calls and sending emails to the appropriate individuals.

Cybersecurity Playground Platform

An app that allows for safe hacking and cybersecurity practices. The app also enables users to start and access sandboxes with multiple machines, such as Windows and Linux. I worked on the back-end side and managed the machines using Ansible.

Energy Products Catalog Scraper

https://github.com/zedosoad1995/energyProductsCatalog
I worked on this project to help a family member to gather information regarding multiple energy products in one place. The program scrapes multiple websites daily and presents them in an interactive table.

Education

2017 - 2019

Master's Degree in Electrical and Computer Engineering

School of Engineering, University of Lisbon - Lisbon, Portugal

2013 - 2016

Bachelor's Degree in Electrical and Computer Engineering

School of Engineering, University of Lisbon - Lisbon, Portugal

Skills

Libraries/APIs

Node.js, React, RxJS

Tools

Git, Prisma, Amazon Simple Queue Service (SQS), MQTT, Ansible, Firebase Cloud Messaging (FCM), Jenkins

Languages

TypeScript, JavaScript, Python 3, HTML, SQL, Python, C++, C, PHP, CSS

Frameworks

Express.js, Jest, Flask, Tailwind CSS, Cypress, React Native, Angular, Symfony, Next.js

Storage

MongoDB, PostgreSQL, Amazon S3 (AWS S3), Redis

Platforms

Docker, AWS Lambda, AWS IoT, Amazon Web Services (AWS), Kubernetes, Mobile

Other

Mathematics, Physics, Algorithms, Control Theory, Machine Learning, Computer Vision, Front-end

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