Rogério Araújo, Developer in Goiânia - State of Goiás, Brazil

Rogério Araújo

Enterprise Architect and Software Developer

Goiânia - State of Goiás, Brazil
Toptal Member Since
November 5, 2012

Rogério is a full-stack developer with 15 years of experience in software development and architecture. He has worked on several projects, including mobile, desktop, and enterprise search applications, for customers in Brazil and globally. Rogério has also contributed to projects ranging from enterprise search, retail, ticket sales, sports training, finance, and blockchain.

Rogério is available for hire
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Web3.js, React, Node.js, PostgreSQL, MUI (Material UI), TypeORM, Express.js
Andrew Koudijs
Go, React, Redux, AWS Lambda, Amazon Simple Queue Service (SQS)...
Daily AI LLC
APIs, GraphQL, Twilio, Zapier, Node.js, TypeScript, MongoDB, Vercel...


Goiânia - State of Goiás, Brazil



Preferred Environment

Visual Studio Code (VS Code), Git, Node.js, MongoDB, PostgreSQL, GraphQL, React, React Native, TypeScript, NestJS

The most amazing...

...thing I've done is create a social media network for sharing travel experiences and an app for buying and selling private bonds.

Work Experience

2021 - PRESENT

Senior Software Engineer

  • Wrote an admin dashboard to manage projects, products, product types, tokens, and other decentralized finance-related investments.
  • Created API and back-end-related jobs to read blockchain over explorers, like BscScan, and read token information and token pairs to help with asset calculation.
  • Made several UI improvements on the main decentralized finance dashboard and evaluated potential additions to increase tool value.
Technologies: Web3.js, React, Node.js, PostgreSQL, MUI (Material UI), TypeORM, Express.js
2023 - 2023

Go/LeafLogix Developer

Andrew Koudijs
  • Implemented several back-end features, from image processing and fixes.
  • Handled front-end features' implementation and fixes.
  • Worked with several different AWS products, like SQS, Lambda, and S3. Also worked with LeafLogix integration.
Technologies: Go, React, Redux, AWS Lambda, Amazon Simple Queue Service (SQS), Amazon S3 (AWS S3), PostgreSQL, MUI (Material UI)
2022 - 2022

Senior API Engineer | Technology

Daily AI LLC
  • Implemented an API to automate contact information capture.
  • Implemented a Zapier action to receive data from an external app like a Google spreadsheet and store it in a local database.
  • Implemented an API authentication and authorization using Auth0.
Technologies: APIs, GraphQL, Twilio, Zapier, Node.js, TypeScript, MongoDB, Vercel, Serverless Architecture, API Integration
2021 - 2022

React Web and React Native Developer

Worthy Financial
  • Worked on implementing the second version of the web and mobile apps.
  • Managed the Microsoft App Center configuration for staging and production builds.
  • Added complete support for multiple environment configurations.
Technologies: React Native, React, iOS, Android Studio, Android, Xcode, Tailwind CSS, React Native Reanimated, react-spring, Auth0, Plaid, React Query, APIs, Zapier, Auth0 API, Mobile Applications
2019 - 2021

Senior Software Engineer

Leaf Logix
  • Developed a mobile app and integrated it with label and receipt printers.
  • Created improvements and fixes for a POS app, the back end of another app, and SQL queries.
  • Created unit tests. Also created a Docker container to make it easy to use and deploy an ERP database locally to help the user on daily development tasks.
  • Forked, improved, and fixed open source libraries in favor of project needs.
Technologies: Docker Compose, Microsoft SQL Server, Moment.js, TypeScript, LINQ, C#, JavaScript, Microsoft Visual Studio, .NET, ASP.NET Web API, SQL, React Native, Technical Hiring, Code Review, Interviewing, Source Code Review, REST APIs, Next.js, HTML, CSS, API Integration, Node.js, APIs, Mobile Applications
2018 - 2018

Senior Software Engineer

Power Home Remodeling Group
  • Developed a React Native app for Android devices. Added support for CI builds and created unit tests.
  • Helped guide the new app architecture's development. I proposed and implemented the application state management on top of Redux and Redux Sagas, which also integrated with an on-device database to persist user messages.
  • Forked, improved, and fixed open source libraries in favor of project needs.
Technologies: Gradle, CocoaPods, Swift, Android, Java, JavaScript, React Native, Technical Hiring, Code Review, Interviewing, Source Code Review, HTML, CSS, API Integration, REST APIs, APIs, Mobile Applications
2017 - 2017

Senior Software Engineer

  • Developed a mobile app using React Native, written entirely from scratch.
  • Proposed libraries to be used. This is one of the projects where redux-sagas were used.
  • Used Realm for data storage which is fast and compact for application needs.
  • Created reusable reducers and sagas, improving codebase maintenance.
Technologies: Realm, Redux-Saga, Redux, React Native, HTML, CSS, API Integration, REST APIs, APIs, Mobile Applications
2016 - 2017

Senior Software Engineer

Digital Gravity Media
  • Developed an Android app.
  • Added beta testing support with Testfairy.
  • Created reusable business logic with libraries like Refit.
  • Proposed app design.
  • Used libraries like ModernHttpClient to speed up network calls and NodaTime to make datetime handling easier.
  • Worked with gamification on the app.
  • Managed code readability with the help of Cheeseknife for view injection.
  • Managed app beta testing and preparing for store release.
Technologies: TestFairy, C#, Xamarin, HTML, CSS, REST APIs, APIs, Mobile Applications
2016 - 2017

Senior Software Engineer and Architect

  • Designed and developed a solution architecture. Developed a landing page alongside background jobs and integration with geospatial data.
  • Added several components to the solution architecture, like Heroku, PostGIS, and Algolia for data indexing and search, as well as Node.js and React.
  • Forked, improved, and fixed open source libraries in favor of project needs, mainly React Native-related libraries to solve very specific software limitations.
Technologies: Redux, Algolia, Heroku, Mocha, Enzyme, React, React Native, Technical Hiring, Code Review, Interviewing, Source Code Review, REST APIs, HTML, CSS, Software Architecture, Architecture, Technical Leadership, API Integration, Software Design, Node.js, APIs, Mobile Applications
2016 - 2016

Senior Software Engineer

  • Developed an iOS app.
  • Performed maintenance on an API.
  • Proposed mobile app design improvements.
  • Maintained a back-end API.
  • Proposed usability improvements.
Technologies: Node.js, Stripe, React Native, REST APIs, HTML, CSS, Technical Leadership, API Integration, APIs, Mobile Applications
2016 - 2016

Senior Software Engineer

Refined Edge Solutions
  • Developed for mobile and web.
  • Created reusable components for the UI.
  • Implemented social networking features.
  • Implemented content sharing features.
  • Proposed design improvements for better handling of authentication and sensitive information persistance.
Technologies: Node.js, Redux, React Native, HTML, CSS, REST APIs, Mobile Applications
2015 - 2016

Senior Software Engineer, Architect, Product Manager

  • Architected and developed a fax processing engine. Led the team and managed products. Integrated with payment gateways like NMI and
  • Managed the back end on AWS by fixing logging code on the server application and improving application execution.
  • Added support to OCR using Tesseract to automate the processing of order information for fraud detection.
Technologies: Amazon Web Services (AWS), Cucumber, RSpec, Sidekiq, Redis, jQuery, Bootstrap, MongoDB, Ruby, Ruby on Rails (RoR), REST APIs, HTML, CSS, Technical Leadership, Software Design
2015 - 2015

Senior Android Developer

MEGA, Inc.
  • Integrated with a Parse back end.
  • Integrated with Stripe for payment processing.
  • Handled continuous delivery with TestFairy.
Technologies: Gradle, Crashlytics, Parse, Stripe, Android Studio, REST APIs, HTML, CSS, Mobile Applications
2015 - 2015

Senior Android Developer

  • Created reusable code.
  • Integrated in-app payments.
  • Integrated Google Cloud Messaging.
  • Consumed a RESTful API with Retrofit.
  • Handled dependency injection with Roboguice.
Technologies: Google Cloud Messaging, Retrofit, RoboGuice, Android Studio, HTML, CSS, Mobile Applications
2015 - 2015

Senior iOS Developer

App Factory
  • Integrated RESTful APIs.
  • Handled Apple Pay payments.
  • Proposed mobile app design.
  • Worked with integration tests using XCTest.
Technologies: CocoaPods, JSONModel, AFNetworking, Apple Pay, Stripe, Objective-C, iOS, HTML, CSS, API Integration, Mobile Applications
2015 - 2015

Senior Software Engineer

  • Handled web development using Elixir and Phoenix framework on the back end and Angular with TypeScript on the front end.
  • Handled unit testing with ExUnit.
  • Integrated Chargify to handle subscriptions and recurring billing.
  • Implemented continuous integration with Travis.
  • Implemented test-driven development with ExUnit.
Technologies: TypeScript, Angular, Test-driven Development (TDD), ExUnit, Phoenix, PostgreSQL, Erlang, Elixir, REST APIs, HTML, CSS
2015 - 2015

Senior Software Engineer

Fleetclean, Ltd.
  • Integrated Cocoapods for dependency management.
  • Maintained CodeIgniter-based web services.
  • Developed environment management with Docker.
  • Added integration tests with KIF.
Technologies: MySQL, Docker, CodeIgniter, Objective-C, Core Data, Flurry, CocoaPods, Xcode, iOS, REST APIs, HTML, CSS, API Integration
2014 - 2014

Senior Software Engineer

MODS Management
  • Architected and developed a solution involving Android applications and RESTful web APIs on top of ASP.NET MVC, then maintained reusable code.
  • Kept track of development tasks over a GitHub issues tracker as a solo initiative.
  • Handled acceptance testing with Robotium and proposed improvements on UI/UX.
Technologies: Ninject, SQLite, ORMLite, RoboGuice, Java, LINQ to SQL, Gradle, Android Studio, TestFairy, ASP.NET Web API, IIS, GitHub, Microsoft SQL Server, Android, REST APIs, HTML, CSS
2014 - 2014

.NET Developer

Peter Franklin
  • Maintained a tool to generate a Google Transit Feed.
Technologies: Microsoft Access, Google Docs, Windows Forms (WinForms), C#, HTML, CSS
2014 - 2014

.NET Developer

Robins Golf Logistix
  • Added new features to a golf coach academy portal.
  • Reworked an admin area look and feel using Ajax, Harbour, and .NET-related technologies.
  • Handled front-end development using web standards like MVC, repository pattern, and others.
Technologies: BrainTree, SendGrid, Bower, Bootstrap, Amazon Web Services (AWS), AppHarbor, Less, jQuery, ASP.NET MVC, REST APIs, HTML, CSS, Microsoft Visual Studio
2013 - 2014

Senior C# Developer

American Mortgage Consultants, Inc. (via Toptal)
  • Developed an income analysis application using ASP.NET MVC.
  • Maintained a database model of mortgage-related data.
  • Handled UI development using jQuery UI widgets. Used Ajax to push data to the server and implemented using ASP.NET Web API.
Technologies: TFS, ASP.NET Web Forms, MVC Razor, Microsoft SQL Server, jQuery, CodeSmith, ASP.NET MVC, REST APIs, HTML, CSS, Microsoft Visual Studio
2012 - 2012

Senior iOS Developer

Worry Free Labs, Inc.
  • Developed iOS components.
  • Integrated GitHub libraries.
  • Managed TestFlight.
  • Managed device and profile.
  • Made project estimates.
Technologies: Objective-C, iOS, HTML, CSS, Mobile Applications
2012 - 2012

Software Developer

  • Developed a FAST ESP back end to provide job vacancy and resume searches.
  • Designed an ASP.NET-based search front end using .NET and related libraries.
  • Created PowerShell and batch scripts for pushing database content to a search engine indexer.
  • Built a search front-end prototype in pure ASP.NET with user controls.
Technologies: Microsoft SQL Server, jQuery, FAST ESP, ASP.NET, ASP, HTML, CSS, Microsoft Visual Studio
2007 - 2011

Senior Software Engineer and Architect

Druid Internet Systems
  • Created an iOS application, a Fandango-like app, for a Brazilian customer.
  • Developed an enterprise search solution for a Brazilian mobile carrier site search and call center portal content search.
  • Developed an internet banking front end on top of JavaServer Faces.
  • Architected and developed a web admin module and REST service for URL categorization with FAST ESP content processing integration via Python scripts (document stages).
  • Architected, installed, and supported an Atlassian ecosystem.
  • Developed a restaurant reservation site on top of ASP.NET MVC.
Technologies: Eclipse, jQuery, Apache Tomcat, JBoss, Hibernate, Spring, MySQL, Oracle, PostgreSQL, SQLite, Android, iOS, XML, FAST ESP, Python, Java, HTML, CSS, Software Architecture, Architecture, Technical Leadership, Software Design, Spring JDBC, Spring MVC, Android SDK, Mobile Applications, JSF
2006 - 2007

Software Engineer

FAST Search and Transfer
  • Developed a search front end for the Financial Times, a risk assessment portal prototype.
  • Built a search front end on top of FAST ESP for Vivo, a Brazilian mobile carrier.
  • Co-authored Project Jigsaw, a Java framework for fast development of search engine front ends on top of FAST ESP and JSF.
  • Created FAST ESP stages in Python to enrich indexed documents with appropriate metadata.
Technologies: Python, MySQL, FAST ESP, Hibernate, JSF, Java, HTML, CSS, Technical Leadership, Spring JDBC, Spring MVC, Spring
2005 - 2006

Senior Software Developer and Architect

Court of Justice of Goiás – Brazil
  • Developed and maintained several web applications built on top of PHP and Java languages. JSF, Hibernate, and XDoclet powered all Java applications.
  • Implemented a proof of concept solution on top of Java Portlets with Liferay Portal.
  • Developed a bodyguard library—a set of EL functions to help integrate Spring Security with Facelets.
  • Architected an SSO solution and developed PHP classes to facilitate the integration of a PHP application with JOSSO.
Technologies: PostgreSQL, PHP, Java, HTML, CSS, Software Architecture, Architecture, Technical Leadership, Spring JDBC, Spring MVC, Spring, JSF
2000 - 2005

Software Developer

C&S Computadores e Sistemas
  • Handled ERP solution development using Delphi and Oracle.
  • Created a small set of ASP.NET 1 controls for internal use.
  • Built an eCommerce product on top of PHP and MySQL.
  • Devised a proof of concept application on top of JBoss/J2EE.
  • Developed a field of sales application with .NET Compact Framework.
Technologies: .NET, Palm OS, SuperWaba, J2ME, PHP, ASP.NET, Oracle, Delphi, HTML, CSS, Technical Leadership, Spring JDBC, Spring MVC, Microsoft Visual Studio, Spring, Mobile Applications


A Perl web application written using a Catalyst framework. This web application is used to search for PDFs indexed by Elasticsearch. The goal of this project was for me to learn and practice Perl and Elasticsearch.

WebSocket Rails – Windows Phone
A WebSockets Rails client port for Windows Phone 8 using WebSocket4Net and Json.NET. This is a small project to self-educate on Ruby and Ruby on Rails and train my skills in .NET and related libraries.

WebSocket Rails – Android
A Websockets Rails client port for Android using Jackson for JSON serialization and AndroidAsync for WebSockets communication. This is another open-source project that I created to self-educate and improve my Android and iOS development skills.

XML Builder
A library that provides a DSL for XML authoring on the .NET platform. This library intends to make XML authoring way more intuitive using a builder pattern. It is inspired by the java-xmlbuilder library. for iOS
A Fandango-like iOS app that enables Brazilian customers to browse movies and theaters and purchase tickets. It is 100% written in Objective-C code, interacting with REST APIs serving XML content at the time of app conception.

UnRAR for iOS
This is a port of unRAR library to the iOS platform. Heavily based on CPP implementation, it also inspired the creation of a fork that has several improvements in place. It also has archive and unarchive functions available.

Solr Update Processors
A project that aims to provide several scripts to act as update processors for use at index time on Apache Solr 4. Most of the scripts are in Python, which can be run using the Java implementation name Jython.


Application built as a freelancer for an Italian customer, EasyLight is an application that just help the user to use Playbook to put some light in a dark place.

An iOS app used to buy tickets for a transport system in Italy.

Antibody Review
A PHP + Apache Solr-powered search back end which indexes data from a MySQL database containing antibody information.

An Alamofire extension to allow integration with ReactiveCocoa.

Contributed with min, man, and take-order action implementations on the Flambo API.

A Slack bot that automatically converts quotations from US dollars to Brazilian reals and returns results to the Slack channel. Brazilian Toptalers heavily used this bot in Toptal community channels on Slack.

An open-source collection of string utilities for Go. This library enables developers to implement string manipulation using functions such as Camelize, Capitalize, CleanDiacritics, Humanize, and several others.

A small Go library to help build a human-readable representation of time duration. It is a library that calculates how much time has passed between two dates. The goal is to make time calculation an easier task.

A Qt-based application to test REST APIs


A social network app written on React Native.

Vivo Site Search
Developed the site search back end of, a Brazilian mobile carrier, written in Java 6. Job Vacancy Search
Job vacancy search built on top of FAST ESP enterprise search platform and ASP.NET, coded in C#.


A social network for travelers. Live2leave allow users to share travel experiences by creating notes, itineraries, see which countries they visited, build a wishlist and much more.
Image of React.js Best Practices and Tips by Toptal Developers publication

React.js Best Practices and Tips by Toptal Developers



Ruby, C#, Java, Objective-C, PHP, JavaScript, HTML, CSS, Python, TypeScript, Elixir, SQL, TypeScript 3, XML, Less, Erlang, Swift, Perl, GraphQL, Go, Kotlin, Dart


React Native, Android SDK, ASP.NET MVC, ASP.NET, Spring, JavaServer Faces, Ruby on Rails (RoR), Redux, Loopback, Next.js, Spring Boot, Flask, NestJS, Laravel, ASP, JSF, .NET, MVC Razor, ASP.NET Web Forms, ASP.NET Web API, ORMLite, Core Data, Phoenix, Angular, AFNetworking, JSONModel, Bootstrap, Grails, Tailwind CSS, MUI (Material UI), Express.js, Flutter, Gin-Gonic


Node.js, React, LINQ, CocoaPods, RoboGuice, REST APIs, Facebook iOS SDK, Intercom API, Auth0 API, React Redux, Windows Forms (WinForms), Flurry, Stripe, Retrofit, Sidekiq, Redux-Saga, RxJS, Dwolla API, react-spring, Web3.js


Ninject, Eclipse IDE, Microsoft Visual Studio, Docker Compose, NPM, Gradle, NGINX, lighttpd, Apache Solr, Autofac, Zapier, Mongoose, Apache Tomcat, Visual Studio, Mercurial, CodeSmith, TFS, SendGrid, Google Docs, GitHub, Android Studio, LINQ to SQL, Xcode, Google Cloud Messaging, Crashlytics, RSpec, Cucumber, Mocha, Auth0, Plaid, Git, Kafka Streams, Amazon Simple Queue Service (SQS)


Object-oriented Programming (OOP), Agile Software Development, Functional Programming, Mobile Development, Test-driven Development (TDD), DevOps, Agile, Lambda Architecture, Serverless Architecture


MacOS, Windows, Android, iOS, Linux, Xamarin, Amazon Web Services (AWS), Oracle, FAST ESP, JBoss, Eclipse, AppHarbor, TestFairy, Docker, Parse, Heroku, Algolia, Visual Studio Code (VS Code), Kubernetes, Amazon, Twilio, AWS Lambda


Enzyme, Apache Commons, API Integration, APIs, Mobile Applications, LogRocket, React Query, Software Architecture, Architecture, Technical Leadership, Software Design, BrainTree, IIS, ExUnit, Apple Pay, Technical Hiring, Code Review, Interviewing, Source Code Review, React Native Reanimated, IP Networks, Server Configuration, Business Processes, Organizational Design, IT Governance, TypeORM, Nx, Vercel, Product Management, Personal Branding


PostgreSQL, MySQL, SQLite, Microsoft SQL Server, Elasticsearch, MongoDB, Redis, Realm, Amazon S3 (AWS S3)


2014 - 2015

MBA Degree in IT Management

IPOG - Goiânia, Brazil

2001 - 2005

Bachelor's Degree in Computing

Universidade Salgado de Oliveira - Goiânia, Brazil



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