Gustavo Mazzoni Maia Lopes, Developer in Rio de Janeiro - State of Rio de Janeiro, Brazil
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Gustavo Mazzoni Maia Lopes

Verified Expert  in Engineering

Full-stack Developer

Rio de Janeiro - State of Rio de Janeiro, Brazil
Toptal Member Since
October 17, 2016

Gustavo is a highly experienced full-stack developer, problem solver, and fast learner who's always looking for new experiences and challenges that will push him to evolve and be the best he can be. He seeks to contribute to other people's lives and to make a difference in the world. Gustavo is also an easy-going person, a team player, and he has worked in teams of all sizes and different roles, such as the team leader and software architect.


Amazon Web Services (AWS), Sagas, JSON Web Tokens (JWT), Sockets, CircleCI...
Cordova, PostgreSQL, Node.js, Ruby on Rails (RoR), Redux, React, Angular...
Menu for Tourist
Amazon Web Services (AWS), Git, Bootstrap 3, CSS3, HTML5, PostgreSQL, Heroku...




Preferred Environment

Git, MacOS, Unix, Sublime Text

The most amazing... I've done is a multi-platform application for different devices built from the scratch just by myself. It's one of the official apps for Olympics in Rio.

Work Experience

Senior Full-stack Engineer

2017 - PRESENT
  • Built, using React and Rails stack, a SaaS platform in the financial industry to power alternative investments with the leading electronic subscription document technology.
  • Created a reusable React UI components library from scratch with the CSS-in-JS emotion library and Storybook to be used by internal projects.
  • Developed JWT authentication, two-factor authentication, and user session management with multi-sessions and timeout for the inactive user (security).
  • Helped create a high-performance background process, using Sidekiq and Redis, to fully map the most complex subdocuments.
  • Added digital signature to documents with the integration to DocuSign with a wrapper to isolate and reduce impact from new versions.
  • Implemented real-time updates to the platform using WebSockets.
  • Led the product team and was in charge of the hiring and onboarding process.
  • Oversaw the whole workflow from development to production.
Technologies: Amazon Web Services (AWS), Sagas, JSON Web Tokens (JWT), Sockets, CircleCI, Storybook, CSS-in-JS, Leadership, Agile, Git, DocuSign, Sidekiq, PostgreSQL, Redis, Docker, Emotion Library, Redux, React, JavaScript 6, Ruby on Rails 6, Web Development, Full-stack Development, UI Development, GraphQL, REST APIs, Kubernetes

Senior Full-stack Engineer

2016 - 2017
  • Architected the front-end codebase, building modular and reusable components and modules with low coupling.
  • Designed and built a multi-platform application for the web, mobile, and Clover using mainly Angular 2, React, Ruby on Rails, and Node.js.
  • Developed standardized and reusable Sass/CSS components using the BEM methodology for the whole application.
  • Created complex flow-like CSV imports and bulk edits with massive data to be processed in a high-performance manner.
  • Mentored junior developers and standardized code styles and best practices.
Technologies: Cordova, PostgreSQL, Node.js, Ruby on Rails (RoR), Redux, React, Angular, PhoneGap, Mobile Development, Web Development, REST APIs

Lead Software Engineer | Full-Stack Developer

2014 - 2016
Menu for Tourist
  • Built the Menu for Tourist app ( It is a mobile app designed to make menus from restaurants around the world more understandable to foreign tourists. Through the app, tourists can access the menu of the restaurant in their native language.
  • Was hired in the early stages to be the principal software engineer; solely responsible for the (from scratch) design and development of the whole system, including its database, storage, cloud infrastructure, back-end, and front-end (for the web and mobile applications).
  • Deployed, in just over three months of work, the first version of mobile app for Android and iOS (hybrid mobile app) and the web platform published in the market.
  • Built a multi-language learning and translator module that should be able to learn human words and expressions from different languages and it's translations. So in the future, a menu from any restaurant in the world would be translated automatically.
  • Worked on the OCR (optical character recognition) processor to recognize texts from photos taken by the user and then translate it to the user's chosen language. To get the better and faster performance of the OCR process, I developed this operation in native code (Android and iOS) and integrated it into our hybrid mobile app in Ionic and Cordova as a Cordova plugin.
  • Recognized as an official app for the Olympics Rio 2016.
Technologies: Amazon Web Services (AWS), Git, Bootstrap 3, CSS3, HTML5, PostgreSQL, Heroku, Sidekiq, Redis, jQuery, Ionic, AngularJS, JavaScript, Ruby on Rails (RoR), Ruby

Lead Software Engineer

2014 - 2014
Dataprev | The Company of IT and Social Security Under the Ministry of Welfare in Brazil
  • Led the tech team and was responsible for ensuring that the applications in the production environment are working according to the SLA.
  • Profiled and monitored a range of tools for performance tuning, scalability, concurrency control, and reliability.
  • Created development recommendations, patterns, and reusable components for better performance.
Technologies: WebLogic, Oracle, JMS, Java EE, Java

Software Developer | Software Architect

2006 - 2014
Dataprev | The Company of IT and Social Security Under the Ministry of Welfare in Brazil
  • Was responsible, along with a team, for designing and building large scale and distributed applications that served millions of users (mostly Brazilian citizens) using mainly Java EE technologies like JSF 1.2, EJB 3.0, JMS, JPA, and Spring Frameworks hosted in Oracle OAS and WebLogic distributed servers integrated with an Oracle database, as well as with JUnit and Selenium for tests, Maven for building and management, and Hudson for CI and CD.
  • Served as the lead software architect of a team and designed architectural solutions, built a POC, and developed, improved, and maintained Dataprev's framework, handled the quality control of the apps (tests/code review), and the CI tools (integration, monitoring, and optimizing).
  • Designed and developed the Integrated Social Benefits System (SIBE) for MPS/INSS (governmental agencies), who manages every social benefit received by all the taxpaying citizens in Brazil. It's a distributed and large-scale app with a huge database. AIt was a project with a duration of over five years with more than ten teams spread across five states in Brazil.
  • Worked for over a year as a project leader for the SAA app (System Authorization and Access): a security system which by law is the security control of all intranet systems developed by Dataprev for its clients (INSS, MPS, RFB, and MTE).
  • Taught as an internal training instructor for EJB3/JPA (basic and advanced).
Technologies: Spring, Selenium, JUnit, Hudson, Ant Design, Apache Maven, JBoss, WebLogic, Oracle, CSS3, HTML5, JavaScript, JPA, JMS, Enterprise Java Beans (EJB), JSF, Java EE, Java

CTO | Co-Founder

2013 - 2013
  • Worked for Audiopeia, a startup focused on the soundtrack market, and delivers an easy and quick way for customers to find and purchase the soundtracks for their projects.
  • Built the website that was a marketplace where customers could buy soundtracks posted by our community of audio producers.
  • Fully participated in the development of the platform from the front end to the back end and infrastructure.
  • Coordinated activities as the CTO that were related to the development of the marketplace platform.
  • Participated, as the co-founder, in the management of the company via contact and presentations to clients and partners, and other related activities.
Technologies: Amazon Web Services (AWS), Git, Heroku, CSS3, HTML5, JavaScript, AngularJS, Ruby on Rails (RoR), Ruby

Software Architecture Manager

2012 - 2013
Dataprev | The Company of IT and Social Security Under the Ministry of Welfare in Brazil
  • Managed the software architecture team at Dataprev (Santa Catarina, Brazil).
  • Restructured a new work process and standardization.
  • Created a technical knowledge base.
  • Improved the assistance of the software projects.
Technologies: Java EE, Java

Web Developer

2005 - 2006
Softplan | Poligraph
  • Developed web applications for government agencies.
  • Supported customers with training and issues.
  • Developed front-end JavaScript components for reuse in different projects.
Technologies: MySQL, Oracle Database, CSS, HTML, JavaScript, Java EE, Java

Menu for Tourist | App

Menu for Tourist is a mobile app designed to make menus from restaurants worldwide understandable to foreign tourists. Through the app, tourists can access a restaurant's menu in their native language. It was an official app for the Rio Olympics 2016.

Photo Mosaic App
A pure JavaScript client-side app that loads an image and generates a photo-mosaic of the original image, through parallel and asynchronous functions using HTML5 features like web workers and Promises.

Ascii Faces eCommerce | AngularJS & Node App
This is an eCommerce site, where you can buy all sorts of ascii faces like (ノ・∀・)ノ and ¯_(ツ)_/¯, in a wide variety of font sizes.

Developer Shop eCommerce | React & Node App
A React and Node.js single-page eCommerce application integrated with GitHub API and MongoDB database.

This is an eCommerce application where a user can shop for developers from an organization in GitHub.

Real-Time Auction | Angular, Socket.IO, and Node App
A real-time app built with Angular, Node, and Socket.IO (integrated with MySQL database).

A single-page application built using AngularJS, for the client side, integrated it to the Node back-end via Socket.IO to keep clients connected; it synchronizes in real-time to every client on any update.

Travel Planner | Angular & RoR App

Angular single page application integrated with Ruby on Rails RESTful APIs with authentication (JWT) and authorization.

Apple Store Top Rank API
A Ruby on Rails API that pulls the Apple App Store top lists from US and provides additional metadata information for each of the IDs returned.

Optical Character Recognition (OCR) Cordova Plugin
An open source Cordova/Ionic plugin for OCR process using the Tesseract library for both Android and iOS. Tesseract is an open source library for OCR (Optical Character Recognition) process.

News Collector | Ruby App
A Ruby application to collect and aggregate news data from a URL and publish it to Redis.

The application accesses a URL containing a list of zipped files. Each zipped file contains a bunch of XML files. Each XML file contains 1 news report.

The application downloads all of the zipped files, extracts out the XML files, and publishes the content of each XML file to a Redis list.

The application is idempotent. It is able to run it multiple times, but to not retrieve duplicate data from the Redis list.
2009 - 2011

Master's Degree in Software Engineering

Universidade Gama Filho - Rio de Janeiro, Brazil

2003 - 2006

Bachelor's Degree in Technology and Computer Networking

SENAI Florianópolis (CTAI) - Florianópolis, Brazil





EMPRETEC Certificate



Certified Programmer for the Java 2 Platform (SCJP), Standard Edition 5.0



Sun Certified Java Programmer



React Redux, REST APIs, React, Sidekiq, Socket.IO, Node.js, jQuery, JMS, Emotion Library, Sockets, Facebook API, Twitter API, GitHub API, HTML5 Web Workers


Eclipse IDE, Sublime Text 2, Vagrant, RSpec, Git, GitHub, Sublime Text, Apache Maven, Hudson, CircleCI, NPM, Babel, Mongoose, Grunt, Bower, Mocha


AngularJS, Angular, Ruby on Rails (RoR), Bootstrap, Redux, Bootstrap 3+, Ionic, Bootstrap 3, JSF, JPA, Ant Design, JUnit, Selenium, Ruby on Rails 5, JSON Web Tokens (JWT), Express.js, PhoneGap, Angular Material, Jasmine, Spring, Ruby on Rails 6


Object-oriented Programming (OOP), Database Design, Object-relational Mapping (ORM), Model View Controller (MVC), RESTful Development, Functional Programming, Asynchronous Programming, Agile Software Development, Responsive Development, Testing, Test-driven Development (TDD), REST, Agile, Scrum, Web Architecture, Mobile Development


HTML, Java, TypeScript, HTML5, JavaScript, Sass, CSS, ECMAScript (ES6), CSS3, SQL, Ruby, JavaScript 6, Less, GraphQL


JEE, Docker, MacOS, Linux, Java EE, Oracle, JBoss, Oracle Database, Amazon Web Services (AWS), Heroku, Unix, Kubernetes


JSON, Oracle 11g, MySQL, PostgreSQL, Redis, MongoDB, Databases


API Design, Performance Optimization, Front-end, Architecture, WebLogic, DocuSign, Leadership, CSS-in-JS, Storybook, Sagas, Business, GitFlow, Cordova, Queuing Systems, Apps, Enterprise Java Beans (EJB), Performance, Self-improvement, Productivity, English, Entrepreneurship, Planning, Complex Problem Solving, Web Development, Software Engineering, UI Development, Programming, Computer Networking, Back-end, Full-stack Development, Servers

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