Joao da Silva Fernandes, Software Developer in Porto, Portugal
Joao da Silva Fernandes

Software Developer in Porto, Portugal

Member since July 16, 2019
João is a full-stack developer focused on Ruby on Rails, who also delves into the front end (with React lately) and infrastructure. He started his career mainly working in startup environments until 2017 when he joined Xing, Germany's most active professional network platform. João strives for long-term maintainability through code quality and a proper delivery process where testing, code reviews, and commit history are prioritized.
Joao is now available for hire


  • Xing
    Domain-driven Design (DDD), REST, Mob Programming, Sentry, Graylog...
  • Novicap
    REST, Testing, Agile, GitHub, Amazon Web Services (AWS), RSpec, Heroku, AWS...
  • MovingWorlds
    Bitbucket, REST, Agile, Amazon Web Services (AWS), Git, HTML, AWS, PostgreSQL...



Porto, Portugal



Preferred Environment

React, Ruby on Rails (RoR), Ruby, Visual Studio Code, Git

The most amazing...

...feeling of value I've had was introducing a testing culture to a group of front-end developers and seeing the confidence in our code increase.


  • Senior Software Engineer

    2017 - 2020
    • Ensured GDPR compliance.
    • Migrated some services from Ruby on Rails 4 to Ruby on Rails 5.
    • Added image and video updates for company profiles.
    • Integrated company profiles into the company's iOS app via WebViews.
    • Improved the user experience of recruiter tools by allowing them to perform bulk actions on candidates.
    Technologies: Domain-driven Design (DDD), REST, Mob Programming, Sentry, Graylog, Continuous Integration (CI), Pair Programming, Testing, Object-oriented Programming (OOP), Kubernetes, Docker, Jenkins, Continuous Delivery (CD), Continuous Deployment, Agile, CSS, GitHub, JavaScript,, Capybara, Jest, RSpec, minitest, Git, MySQL, React, Ruby on Rails (RoR), Ruby
  • Senior Software Engineer

    2017 - 2017
    • Migrated the accounting system to a new double-entry system.
    • Improved the GitFlow and code-review culture in the company.
    Technologies: REST, Testing, Agile, GitHub, Amazon Web Services (AWS), RSpec, Heroku, AWS, Git, PostgreSQL, Redux, React, Ruby on Rails (RoR), Ruby
  • Consultant

    2017 - 2017
    • Maintained the platform at a point where no developers had been working on it for months.
    • Optimized back-end admin panels to accommodate the platform activity.
    • Fixed critical bugs that were disrupting the operations team and the users.
    • Hired and onboarded a long-term maintainer for the platform.
    Technologies: Bitbucket, REST, Agile, Amazon Web Services (AWS), Git, HTML, AWS, PostgreSQL, Node.js
  • Software Engineer

    2014 - 2017
    • Worked on financial reconciliation mechanisms with credit card payments and currency transfers.
    • Implemented a site-wide responsive redesign.
    • Built legal compliance mechanisms.
    • Contributed to the development of a platform for the operations team to review crowdfunding pitches sentence by sentence.
    • Created a dashboard for entrepreneurs to manage their crowdfunding campaigns.
    Technologies: Analytics, Mixpanel, Capybara, REST, Testing, Object-oriented Programming (OOP), Responsive UI, Jenkins, Agile, CSS, GitHub, Git, JavaScript, jQuery, Sass, Haml, MongoDB, MySQL, Ember.js, Cucumber, RSpec, Ruby on Rails (RoR), Ruby


  • Testimonials Page for Alto Pharmacy (Development)

    I collaborated with the design agency, Saint Friend, to implement the testimonials page for Alto Pharmacy. Saint Friend provided the designs for large and small screens, and I implemented them while suggesting solutions for corner cases not contemplated in the designs.

    Technologies: Jekyll, Sass, HTML, JavaScript, jQuery

  • Framework to Navigate Web Pages Using the Microsoft Kinect (Development)

    As part of my master's thesis, I created a C# application that connects to the browser via sockets and sends data from Microsoft Kinect. I then developed a JavaScript framework to allow for user interaction based on motion events. These interactions included pressing buttons, scrolling through the page, image and PDF interactions (pitching, zoom, and rotation), and video interactions.

  • Site-wide Responsive Redesign (Development)

    The current Seedrs' look and feel was introduced in 2015 as part of a responsive redesign that was rolled out on a per-page basis. The pages that I worked on include the investment opportunities page and the how-to-invest page.

    Technologies: Haml, Sass, jQuery

  • Rails 5 Upgrade (Development)

    I led the Rails 5 upgrade of the company profiles section of Xing. It was a ten-year-old legacy project and required exhaustive controller test refactoring, dependency updates, and removal of legacy mass assignment code from Rails 3.

  • Head of the Program for Portugal's National Conference of IT Students (ENEI 2013) (Other amazing things)

    In 2012, I was invited to take ownership of the program for 2013's ENEI. This project involved choosing, contacting, and scheduling speakers on topics such as information security (infosec), internet of things (IoT), web development, and mobile computing. The attendance forecast was of 300 attendees. However, we ended up having 600 attendees, which led to a last-minute expansion of the program.

  • Talk | Mob Programming to Deliver Better Software (Other amazing things)

    I gave a talk at Pixels Camp 2019 on how to use mob programming to deliver more maintainable code with fewer defects. This practice reduces the back-and-forth actions in code review processes by having the team collaborate in a disciplined manner and providing feedback in real-time before the code gets to the code review step.


  • Languages

    Ruby, JavaScript, CSS, HTML, Sass, Haml
  • Frameworks

    Ruby on Rails (RoR), minitest, Jest, Redux, Ember.js,, Capybara
  • Tools

    Git, GitHub, RSpec, Graylog, Sentry, Cucumber, GitLab, Bitbucket, Jenkins
  • Libraries/APIs

    React, jQuery, Node.js, Marionette.js
  • Paradigms

    Agile, Scrum, Kanban, Object-oriented Programming (OOP), Testing, Pair Programming, Mob Programming, Continuous Deployment, Continuous Delivery (CD), Continuous Integration (CI), REST, Functional Programming
  • Platforms

    Heroku, Visual Studio Code, Amazon Web Services (AWS), Docker, Kubernetes, Mixpanel, Unix
  • Storage

    PostgreSQL, MySQL, MongoDB
  • Other

    AWS, Domain-driven Design (DDD), Analytics, Responsive UI


  • Master's degree in Software Engineering
    2009 - 2014
    University of Porto, Faculty of Engineering - Porto, Portugal

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