Publication
A Year Building a WebRTC Application: Lessons in Startup Engineering
https://www.toptal.com/developers/ruby-on-rails/a-year-with-webrtc-lessons-in-startup-engineering
Alexandre is available for hire
Hire AlexandreAlexandre Mondaini Calvão
Verified Expert in Engineering
Ruby on Rails Developer
Rio de Janeiro - State of Rio de Janeiro, Brazil
Toptal member since October 5, 2012
Bio
Alexandre is an expert Ruby on Rails developer who is also experienced with Java and various front-end technologies. In addition, he's worked extensively with WebRTC, building video-based web apps from scratch and many back-end APIs to be consumed by Angular and React.
Portfolio
Spectora, Inc
Ruby on Rails (RoR), Amazon Web Services (AWS), Cursor AI, React, n8n...
FCP Euro
Ruby on Rails (RoR), CSS, JavaScript, HTML, RSpec, eCommerce, Solidus, DevOps
Owens Corning
Ruby on Rails (RoR), Ruby, JavaScript, PostgreSQL
Experience
- Ruby on Rails (RoR) - 15 years
- PostgreSQL - 8 years
- Ruby - 8 years
- JSON - 7 years
- Java - 5 years
- JavaScript - 4 years
- Agile Software Development - 3 years
- Python - 1 year
Work Experience
Full-stack Ruby on Rails/AWS Developer
2025 - 2026
Spectora, Inc
- Developed back-end integrations connecting the home inspection platform with third-party services to automate post-inspection data workflows.
- Built webhook endpoints to enable bidirectional data sync between the inspection platform and external partner systems.
- Delivered new features on a multi-tenant Ruby on Rails SaaS platform serving thousands of home inspection professionals.
- Implemented feature flagging to support safe, gradual rollouts of new functionality across the customer base.
- Designed and shipped background job pipelines to process inspection reports asynchronously and reliably at scale.
- Refactored legacy service code to follow established architectural patterns, improving maintainability and reliability.
- Collaborated with cross-functional teams to scope, design, and deliver features aligned with product and business priorities.
- Added structured logging and observability to key services, reducing time-to-diagnosis for production issues.
- Enforced code quality standards and best practices across all contributions, ensuring consistency with the team's conventions.
Technologies: Ruby on Rails (RoR), Amazon Web Services (AWS), Cursor AI, React, n8n, PostgreSQL, Claude, Sidekiq, Redis, Stripe
Full-stack Developer
2024 - 2024
FCP Euro
- Developed an integration with Contentstack to display products dynamically on the main website, enhancing the user experience and improving content management efficiency.
- Resolved multiple high-priority bugs in the existing system, reducing site downtime and improving overall system stability and performance.
- Collaborated with cross-functional teams to ensure seamless product integration and timely delivery of features, meeting all project deadlines.
- Optimized back-end code, reducing page load times, which improved the user experience and SEO performance.
Technologies: Ruby on Rails (RoR), CSS, JavaScript, HTML, RSpec, eCommerce, Solidus, DevOps
Senior Ruby on Rails Developer
2022 - 2024
Owens Corning
- Led developing and deploying several React-based web applications, improving user interfaces and enhancing the overall customer experience.
- Collaborated with data science teams to integrate AI solutions into core business processes, resulting in improved decision-making and automation.
- Developed microservices in Go, optimizing system performance and scalability for large-scale, high-traffic applications.
- Worked with cloud-based infrastructure (AWS/GCP) to deploy and manage scalable services, improving system reliability and reducing operational costs.
Technologies: Ruby on Rails (RoR), Ruby, JavaScript, PostgreSQL
Senior Full-stack Developer
2020 - 2021
Only One, Inc.
- Built an API from scratch for use with an Angular front end.
- Integrated the back end with many technologies like Stripe and Campaign Monitor.
- Worked on the Angular front end to fully support the token authentication system.
Technologies: Ruby on Rails (RoR), Angular
Senior Ruby on Rails Developer
2019 - 2019
Canadamark
- Developed many functionalities using Rails-related technologies for both back and front-end.
- Managed AWS instance servers and created new ones for other environments.
- Implemented Capistrano to ease the deployment of the application on many servers.
Technologies: Ruby on Rails (RoR), Unix, Amazon Web Services (AWS)
Cordova Developer
2019 - 2019
Zoomee
- Updated the Rideshare app for both Android and iOS.
- Updated the Ruby on Rails back end from Rails 3 to 4 and all required gems.
- Created new functionalities on the active admin dashboard.
Technologies: Cordova
Senior Full-stack Developer
2019 - 2019
One Love
- Created a fully responsive website using Bootstrap.
- Managed a DigitalOcean server with Capistrano and related technologies.
- Developed back-end features in Ruby-on-Rails using the ActiveAdmin gem.
Technologies: Capistrano, Bootstrap, CoffeeScript, Ruby on Rails (RoR), Ruby
App Developer
2018 - 2018
We Are Alexander
- Implemented database storage for long value persistence.
- Debugged the Salesforce authentication process.
Technologies: Salesforce, Angular, iOS, TypeScript, Ionic
Full-stack Developer
2018 - 2018
Munchery
- Created an API for third-party integration.
- Supported the Engine Yard deployment process.
- Changed the React front-end based on AB testing results.
- Provided TDD development of back-end functionalities.
- Generated automated API documentation.
Technologies: Amazon Web Services (AWS), Engine Yard, Docker, MySQL, React, Ruby on Rails (RoR)
Senior Full-stack Developer
2018 - 2018
Ygrene
- Constructed a front-end application using Angular 6, Ngrx, and Nx for multiple Angular applications.
- Implemented CSS and HTML using the flex-layout system.
- Integrated the back-end with many external system APIs.
- Constructed a back-end API for the front-end application to access.
- Made a Bitbucket Pipeline improvement to run specs on the Rails application.
Technologies: Angular Flex Layout, NgRx, Bitbucket Pipelines, Angular, RSpec, Docker, Ruby on Rails (RoR)
Owner
2016 - 2017
Moca Tecnologia
- Created some Unity games as I delved into the world of startup ownership.
Technologies: Unity3D, C#
Senior Ruby on Rails Developer
2014 - 2016
Procore
- Integrated a Quickbooks Desktop application with the Procore web app through a web connector that makes SOAP calls to a specified endpoint.
Technologies: JSON, APIs, SOAP, Ruby on Rails (RoR)
Team Leader
2012 - 2014
HelloMd
- Created numerous applications using WebRTC technology.
- Managed outsourced employees based in Vietnam.
- Started a tech company from zero.
Technologies: WebRTC
Developer
2011 - 2012
SESEG
- Designed and developed systems for for support of the daily activities of the secretary.
- Implemented various functionalities using the test-driven design methodology with RSPEC.
Technologies: Capybara, RSpec, CSS, CoffeeScript, Haml, NGINX, Unicorn, Ubuntu, Git, Ruby on Rails (RoR), Ruby
Developer
2009 - 2011
Ideais
- Developed a web service using REST for interfacing a web service with a SOA Web Service.
- Developed several REST services that transcribe calls for SOA, allowing access to the CMNET system for hotel booking.
- Developed a system for the remittance of scheduled emails and for template registration.
- Added user control to a system already in production, along with single sign-on functionality for other systems.
Technologies: Ant Design, Apache Maven, Hibernate, Spring, JavaScript, JSF, Java
Project History
Procore Quickbooks Integration
https://www.procore.com/I created a Ruby on Rails microservice that would receive a call from the QuickBooks desktop software and send it to the main software. The software was created using the Ruby on Rails and the calls were made using the SOAP protocol. Rspec was used as the test framework.
One Love
Creation of the fully responsive website for the version 2 of the findmymission.com website.
Qbwc_requests
https://github.com/apotema/qbwc_requestsAn open-source Ruby gem to create Qbwc requests that makes easy for developers to generate Quickbooks requests. It uses RSPEC as the test framework.
Física Básica (Basic Physics)
A mobile application to teach physics, created using Ionic and Angular. The app has 4 years of development and has been used by more than 200,000 users.
You can also see the iOS version here:
https://itunes.apple.com/us/app/mecanica/id880245410
You can also see the iOS version here:
https://itunes.apple.com/us/app/mecanica/id880245410
Marcações (Ionic)
This Ionic app connects to a Ruby on Rails back-end to manage the schedule of appointments of the users.
The app is fully created using the Ionic framework and Angular JS,
The app is fully created using the Ionic framework and Angular JS,
Paper Hero
A Unity3D game created by me.
Banco de Talentos
I developed an application for the registration of applicants with interest in lecturing on military policy. Further, I developed a second application for the consultation of the applicant’s information and expertise.
Socitrip
A defunct Ruby on Rails app to manage users' travel recommendations, the app had many functionalities, like Facebook integration.
Gamc
Personal project under active development.
Wikimapa
Wikimapa was an Brazilian startup that was aiming to map slums of Brazil. The web app was made using the Rails framework, with an API to be managed by the mobile app.
MIMO
Mimo was a startup that use to offer photo books that you could create yourself where I created the whole system using Ruby on Rails and many other JS libraries to manage the creation of the photo albums.
Go-Active-Interaction
https://github.com/apotema/go-active_interactionGo ActiveInteractation is based on active_interaction and aims to bring the power of the Ruby gem to the Go space.
This library shows my passion for contributing to the open-source community and working with the Go language.
This library shows my passion for contributing to the open-source community and working with the Go language.
Ruby on Rails Development
https://www.owenscorning.comAs a senior Ruby on Rails developer at Owens Corning, I utilized React for front-end development and Ruby on Rails for back-end solutions. Additionally, I implemented AWS Lambda integrations using Go and handled API integrations with various services.
Education
2004 - 2009
Graduate Degree in Computer Science
Universidade Federal Fluminense - Niteroi, Rio de Janeiro, Brazil
Certifications
AUGUST 2009 - PRESENT
SCWCD – Sun Certified Web Component Developer
Sun Microsystems
JANUARY 2009 - PRESENT
SCJP - Sun Certified Java Programmer SE 6
Sun Microsystems
Skills
Libraries/APIs
WebRTC, NgRx, Angular Flex Layout, React, Salesforce API, Facebook API, jQuery, Sidekiq, Stripe
Tools
RSpec, Apache, Git, NGINX, Apache Maven, Capistrano, Microsoft Excel, Adobe Fireworks, FileZilla, n8n, Claude
Languages
Ruby, C#, SQL, JavaScript, Java, Go, Unicorn, Haml, CSS, TypeScript, Python, CoffeeScript, PHP, HTML
Frameworks
Ruby on Rails (RoR), Ionic 3, Unity3D, Ionic, Capybara, PhoneGap, AngularJS, JSF, Spring, Hibernate, Ant Design, Angular, Bootstrap, JavaServer Faces
Paradigms
Test-driven Development (TDD), Agile Software Development, DevOps
Storage
JSON, PostgreSQL, SQLite, Oracle SQL, MySQL, Redis
Platforms
Ubuntu, MacOS, Docker, Engine Yard, iOS, Salesforce, Amazon Web Services (AWS), Unix, Windows, Linux, Solidus
Other
Full-stack Development, Legacy Software, SOAP, APIs, Bitbucket Pipelines, Cordova, Computer Science, eCommerce, Cursor AI
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