João Paulo Lethier, Developer in Florianópolis - State of Santa Catarina, Brazil
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João Paulo Lethier

Verified Expert  in Engineering

Software Developer

Location
Florianópolis - State of Santa Catarina, Brazil
Toptal Member Since
February 14, 2014

João is a retired basketball player and has been a web developer and coder since 2009. He has created a variety of complex web apps using Ruby on Rails and has a variety of personal interests in multimedia and entertainment. He communicates well and understands the ins and outs of the development lifecycle.

Portfolio

Goco.io
Ruby on Rails (RoR), Ruby, GraphQL, Test-driven Development (TDD)
PagSeguro Digital
Ruby, Ruby on Rails (RoR), Oracle, Leadership, Agile, Kanban
Zygo Tecnologia
Amazon Web Services (AWS), React, Ruby on Rails (RoR)...

Experience

Availability

Part-time

Preferred Environment

Sublime Text, Ruby on Rails (RoR), Ruby

The most amazing...

...thing I've created is the entire academic management system currently used by my university.

Work Experience

Staff Engineer

2023 - PRESENT
Goco.io
  • Developed a GraphQL API to support the front-end features.
  • Worked with automated tests to guarantee the needed code coverage and quality.
  • Reviewed other team members' PRs, giving suggestions for improvements.
Technologies: Ruby on Rails (RoR), Ruby, GraphQL, Test-driven Development (TDD)

Engineering Manager

2020 - 2022
PagSeguro Digital
  • Led and managed a diverse team with Android, back, and front-end developers.
  • Planned the goals, measured, and supported the team to deliver and accomplish them.
  • Did one-on-one meetings with my team, supporting them in their career paths, planning their next goals, and leading them in day-to-day tasks.
  • Reviewed PRs of the team and gave technical advice, helping them to deliver the best technical solution.
Technologies: Ruby, Ruby on Rails (RoR), Oracle, Leadership, Agile, Kanban

CTO

2014 - 2020
Zygo Tecnologia
  • Developed and helped build some APIs for mobile apps using RoR and TDD.
  • Created an admin system to manage and control all information in the database and develop actions that mobile apps should use.
  • Assumed the CTO position in 2018 and started to manage a small development team with five developers. The team grew to have more than ten developers and worked on API, SPA, and Android development.
  • Managed and updated all gems and frameworks used in the project.
Technologies: Amazon Web Services (AWS), React, Ruby on Rails (RoR), Test-driven Development (TDD), PostgreSQL, Leadership, Agile

Web Developer

2013 - 2014
Chegue.La
  • Developed an API using Doorkeeper and Rails to serve all site functionalities for other clients, letting them sell bus tickets on their own website using the Chegue.La API.
  • Developed the payment flow using Pagar.me API.
  • Handled unit and integration tests using RSpec and Capybara.
  • Conducted market research about hotels, tickets, and travel agencies to help the company choose the next step in the business plan.
  • Coded background jobs to access the J3 API, a tool that lets users access information about bus tickets, bus companies, and send bus tickets.
  • Designed payment pages.
Technologies: Heroku, jQuery, JavaScript, JSON, PostgreSQL, MySQL, SQL, Ruby on Rails (RoR)

Web Developer

2013 - 2013
Rede Jovem
  • Developed a social map system using Rails.
  • Scaled the social map system using Memcached.
  • Met with the product owner to define project sprints.
  • Handled geolocation using a geocoder gem.
  • Developed a map system that lets users draw streets in Google Maps.
  • Created automated tests using RSpec.
  • Deployed using a Capistrano gem.
Technologies: Capistrano, PostgreSQL, Facebook API, Google Maps API, jQuery, JavaScript, Ruby on Rails (RoR)

Web Developer

2012 - 2013
XL Solutions
  • Worked in web development using Ruby on Rails.
  • Implemented designs using SASS and Haml.
  • Developed an e-learning system.
  • Developed a video broadcast system.
  • Supported development in all other company systems, including eCommerce.
  • Worked as Scrum Master for two projects, Exerça Sua Fé and Atos.
  • Met with customers to do presentations and plan sprints.
  • Automated tests with Cucumber and RSpec.
Technologies: RSpec, JSON, jQuery, MySQL, SaaS, Ruby on Rails (RoR)

Web Developer

2011 - 2012
VentureOne Startups
  • Handled web development of a product named Zupty.
  • Participated in company product investment decisions.
  • Conducted market research about security software, testing HP, IBM, and other software solutions in this market.
  • Automated tests using RSpec.
Technologies: Haml, JavaScript, Sass, Ruby on Rails (RoR)

Web Developer and Scrum Master

2009 - 2011
Universidade Federal Fluminense - UFF
  • Developed a system that controls generation of bachelor's degrees.
  • Supported all academic systems including student enrollment, course management, teacher access, and student grades.
  • Developed using Java, Hibernate, Maven, Spring, and Oracle.
  • Worked as Scrum Master of a bachelor's degree system.
  • Spoke with customers and system users.
Technologies: CSS, Spring, Apache Maven, Hibernate, PostgreSQL, Oracle, Java

Full-stack Engineer in a Ruby On Rails Project

A Rails 7 application with external services like square and Twilio. The project was built on top of the new tools of Rails 7, like Hotwire, Turbo, Streams, and Stimulus. Everything was developed using automated tests and the best practices, using tools like Rubocop, RSpec, and Brakeman.

Ofertus

A tool for social offer recommendations. Users can recommend offers they support and make money when other users buy the offer.

The entire offer-sharing mechanism is automated; users just need to share the link, and the system gets all the required information (price, title, discount, etc.) directly from the link.

Atos - Escola Cristã de Liderança

An e-learning system for a church in Rio de Janeiro that allows students to watch lessons and take tests. Teachers and employees can also manage all students, lessons, subjects, and courses.

I worked as the lead developer and scrum master for this project,

Bonuz

A loyalty mobile app with offers and rewards for users. All communication is doing through an API built on Ruby on Rails, which was the main responsibility of the team I was allocate to develop and maintain. We built the API with RSpec tests, using MySQL as a database.

Companion

We build a web system and a mobile app(react native) where user can see results of his store, how many sells, customer statistics, revenue, reviews. On the web user can interact with customers too, creating offers, sending gifts.

There is a desktop app too, built with Electron, which works on store to give real-time interactions with customers.

CofeTeam

A small website to let a company sells its services

Bruna e João Paulo

My wedding website.

Minha Sala de Aula

This is a school system to help students to interact with other students, teachers, and directors. Students can see the school calendar and test calendar, and they can post and search in subject forums.

Certexa

Company website.

Languages

Ruby, Haml, JavaScript, SCSS, Java, CSS, Sass, SQL, Python, GraphQL, HTML

Frameworks

Ruby on Rails (RoR), Capybara, Hibernate, Spring, Angular, Ionic, AngularJS, React Native, Stimulus

Libraries/APIs

Sidekiq, React, jQuery, Facebook API, Google Maps API, React Redux, Google Maps, Pundit, Square API, Mechanize

Tools

RSpec, Apache Maven, Capistrano, Sublime Text, Adobe Photoshop, Amazon Simple Notification Service (Amazon SNS), Turbo

Paradigms

Test-driven Development (TDD), Behavior-driven Development (BDD), Agile, Kanban, Scrum

Platforms

Heroku, Amazon EC2, MacOS, Linux, Amazon Web Services (AWS), Oracle

Storage

Memcached, PostgreSQL, Redis, Amazon S3 (AWS S3), MySQL, JSON

Other

Leadership, SaaS, Hotwire, Ruby on Rails 7, SMS, Entrepreneurship, Computer Science, Development, Streaming

2009 - 2011

Technical Degree in Entrepreneurship

Universidade Federal Fluminense - Niterói, RJ, Brazil

2007 - 2011

Bachelor's Degree in Computer Science

Universidade Federal Fluminense - Niterói, RJ, Brazil

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