Cassio Tavares, Developer in Belo Horizonte - State of Minas Gerais, Brazil
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Cassio Tavares

Verified Expert  in Engineering

Back-end Developer

Belo Horizonte - State of Minas Gerais, Brazil
Toptal Member Since
May 1, 2020

Cassio Tavares is a software engineer who loves technology. He has more than 15 years of experience, and he continues to study and learn every day. With his experience, he has helped companies design and develop projects that are an important source of income. Cassio has the mindset of an entrepreneur with a science and technology background.


Toptal Clients
C#, .NET, APIs, Git, MySQL, Microsoft SQL Server, Third-party APIs...
Exemplar Human Services, LLC
ASP.NET, Architecture, Agile, Database Architecture, APIs, Data Structures...
Data Frontline, Inc.
SQL, C#, .NET, C++, JavaScript, REST API Architecture, Back-end...




Preferred Environment

RavenDB, MySQL, Internet Information Services (IIS), Visual Studio, Windows, Multithreading

The most amazing...

...experience I've had was saving a company from probable bankruptcy by leading the development of their core systems in new technologies.

Work Experience

Software Engineer

2020 - PRESENT
Toptal Clients
  • Worked for many different clients, mainly from the United States and Europe, on different kinds of projects.
  • Used .NET as the main platform for development, but I also converted Visual Basic 6.0 (VB6) code to C# in one of them. I also built one automation tool with C# to manipulate another app.
  • Utilized Git as a source control tool in most of the projects. We also used Jira in two projects.
Technologies: C#, .NET, APIs, Git, MySQL, Microsoft SQL Server, Third-party APIs, Microsoft Visual Studio, Database Architecture, Data Structures, API Integration, Entity Framework, REST API Architecture, Back-end, Windows Server, Back-end Development

Back-end Developer

2023 - 2023
Exemplar Human Services, LLC
  • Refactored the solution to the new architecture, improving code reuse and test coverage and having less class coupling.
  • Used .NET Core, an ASP.NET Web API, and Entity Framework Core. Created integration with external API.
  • Finished the project on time so the client could present with the new app.
  • Tracked and fixed bugs and suggested and implemented new features.
Technologies: ASP.NET, Architecture, Agile, Database Architecture, APIs, Data Structures, .NET, C#, CI/CD Pipelines, Azure, API Integration, Entity Framework, REST API Architecture, Back-end, Back-end Development

.NET Developer

2023 - 2023
Data Frontline, Inc.
  • Tracked and fixed bugs and created new functionalities to enhance the system.
  • Separated the services onto different servers, created a development environment, and used Git for source control.
  • Helped to understand table structures and stored procedures. Republished the system on a new production server.
Technologies: SQL, C#, .NET, C++, JavaScript, REST API Architecture, Back-end, Back-end Development

Back-end Developer | Healthcare Leading Company

2022 - 2022
AMN Healthcare - Main
  • Generated some ideas of how the system front end could be modified not to load excessive data, improving the user experience with a much lower loading time.
  • Created diagrams to map all code-called store procedures that would be impacted by archiving old data. Later had to write the code to archive entities and not return them from the store procedures.
  • Created code to measure time inside and between methods to run in a production environment. Used NLog to log data and Rapid7 to filter and analyze it.
Technologies: C#, .NET, Microsoft SQL Server, Microsoft Visual Studio, REST API Architecture, Back-end, Windows Server, Back-end Development

Software Architect

2016 - 2019
  • Led a team of four to create a web solution to replace the prior system. Brought to the company a new idea, and from that, created a product that guaranteed a contract with the biggest oil company in the world.
  • Led the team to rewrite the legacy Delphi and Oracle database system to the web using .NET and C#.
  • Helped in the transition from local servers to AWS.
  • Presented the product at AAPEX and SEMA Show. Talked with AC Delco, Mobil, Chevron, eBay Motors, R.O.W.E Oil, Amro, and others.
Technologies: Bootstrap, GitHub, Git, .NET Core, HTML, IIS, JSON, Software Architecture, SQL, C#.NET, REST APIs, NoSQL, Object-oriented Programming (OOP), Visual Studio .NET, Web API 2, Back-end, JavaScript, Riot.js, RavenDB, .NET, C#, Third-party APIs, Microsoft Visual Studio, APIs, Architecture, REST API Architecture, Windows Server, Message Queues, Back-end Development


2010 - 2016
  • Started my own company and worked as an independent IT consultant. At this time I played many roles in different industries (healthcare, engineering, telemetry), using different technologies.
  • Contributed to software development, server management, database management, application integration, IT costs reduction and other IT consultancies.
  • Joined the Gorges USA team to track and solve bugs, and improve performance.
  • Created an application to follow PDCA methodology. It was for management of quality, security, and the environment, based on ISO 9001, 14001, and OHSAS 18001.
Technologies: Git, HTML, IIS, JSON, Software Architecture, SQL, C#.NET, REST APIs, NoSQL, Object-oriented Programming (OOP), Visual Studio .NET, Web API 2, VMware ESXi, NHibernate, MySQL, Microsoft SQL Server, .NET, ASP.NET Web API, C#, Microsoft Visual Studio, Back-end, Windows Server, Back-end Development, MySQL Server

Software Architect

2003 - 2010
90 Tecnologia da Informação
  • Created an ERP system that is the biggest project of the company. It has hundreds of tables, is used by hundreds of clients, and survived the last 10 years of continuous development.
  • Led a team of four people for four years. I had to choose what technologies to use and teach them to my colleagues.
  • Implemented the first control version system of the company.
Technologies: Software Architecture, SQL, C#.NET, Windows Forms (WinForms), Object-oriented Programming (OOP), Visual Studio .NET, Back-end, NHibernate, Microsoft SQL Server, Windows Communication Foundation (WCF), .NET, C#, Microsoft Visual Studio, Desktop App Development, Architecture, Database Architecture, Windows Server, Back-end Development, MySQL Server, Windows Services

Intern Developer

2003 - 2003
  • Developed services that should run periodically or triggered by a user. The services should connect to third-party servers (FTP and HTTP) to collect meteorological data.
  • Collected the data to be processed and used to generate some graphs that could help engineers calculate the possibility of floods in some dangerous areas.
  • Chose the technologies (PHP and MySQL), wrote PHP code, and designed the database.
Technologies: PHP, JavaScript, MySQL, MySQL Server

Fleet2Go is a web application that imports driver and vehicle data from Mix Telematics servers and creates a report used by clients to pay their employees. The reports are used even in law courts when there is and disagreement between the employee and the employer.

The solution was composed of two different applications. One importer that uses Mix Telematics APIs to import data and one application for the end-user can generate reports, customize, and administrate other data. The database had more than one Terabyte of data and was stored in an AWS MySQL RDS container.

I was responsible for all the algorithms, UI, database, and AWS environment administration.

Squash Rules Trainer
This is a website that allows squash enthusiasts to train their knowledge of the rules of this great sport. Using some squash matches from YouTube and mapping the referees' decisions, the site allows the users to give an opinion before seeing the official decision.

It is hosted using only free Azure services, which makes it slow to load everything at some times.

Gestor ERP
This is a big app that I helped to create in 2005. I worked on it for five years—choosing the technologies, studying the previous version written in Cobol, creating the first lines of code, designing the database, creating Windows Forms UIs and components, discussing the best approach to solve business process, and much more.

Oil Change App
The app is used by oil change shops to help them find the correct oils for specific models. The app has more than 50,000 engines that are easily found, informing users of the manufacturer, type, year, and model of the vehicle. After the correct engine is selected, the app shows (especially but not only) various brands of oils and parts that can be used on that specific car.

The app is used by more than 3,000 fuel stations and oil change shops.

Behind the app, there is an API that is commercialized to other software vendors where they can get vehicle data to be used in other systems. This part was my idea.

SAP Business One Add-on

An add-on for SAP Business One that allows construction companies to manage their work sites, schedule of values, projects, and stages, allowing them to monitor stage balances, purchases, and blanket agreements. The solution was created using UI API and runs inside SAP Business One. There was also an external reports module that was built with Vue.
2010 - 2011

Postgraduate Degree in Software Architecture

Instituto GTI - Belo Horizonte, Brazil

1999 - 2003

Bachelor's Degree in Computer Science

Pontifícia Universidade Católica de Minas Gerais - Belo Horizonte, Brazil


Improving Deep Neural Networks: Hyperparameter tuning, Regularization and Optimization


Neural Networks and Deep Learning


Mathematical Thinking in Computer Science

UC San Diego - Coursera


REST APIs, API Development, Web API 2, SQLite.NET, Windows Forms (WinForms), Riot.js, Google Sheets API, Entity Framework, YouTube API, Vue


Visual Studio, Visual Studio .NET, Google Sheets, Visual Studio Tools for Office (VSTO), Microsoft Visual Studio, SAP Business One SDK, Git, GitHub, Amazon Simple Notification Service (Amazon SNS), Amazon Simple Queue Service (SQS)


ASP.NET Web API, ASP.NET, ASP.NET Core, .NET Core, .NET, NHibernate, ASP.NET Core 2, Bootstrap


SQL, C#.NET, C#, HTML, JavaScript, CSS, PHP, XML, C++


RESTful Development, REST, Object-oriented Programming (OOP), REST API Architecture, Microservices, Test-driven Development (TDD), Desktop App Development, Agile


MySQL, NoSQL, JSON, MySQL Server, SQLite, RavenDB, Microsoft SQL Server, Database Architecture, SQL Server 2014, MongoDB, Amazon S3 (AWS S3)


Amazon Web Services (AWS), Amazon EC2, Windows Server, Windows, AWS Lambda, Docker, Xamarin, Azure, Azure Functions, SAP HANA


Software Architecture, APIs, Code Architecture, Back-end, API Integration, Back-end Development, Internet Information Services (IIS), Architecture, IIS, Third-party APIs, Data Structures, Deep Learning, VMware ESXi, Windows Communication Foundation (WCF), Remoting, IIS 10, CI/CD Pipelines, Message Queues, Multithreading, SAP Business One, Windows Services

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