Walmor Costa Moreira, Developer in São Paulo - State of São Paulo, Brazil
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Walmor Costa Moreira

Verified Expert  in Engineering

Software Developer

São Paulo - State of São Paulo, Brazil
Toptal Member Since
August 27, 2018

Walmor has over 12 years’ experience architecting and developing mission-critical applications in different platforms and technology stacks, including React, Node.js, GraphQL, and .NET. Concerned about code quality, he has a high interest in best practices, methodologies, and software principles. Having good communication and analytical skills, he has been working closely with business managers, helping design solutions for a variety of problems.


DevReady, Denver, CO
Azure, Redis, PostgreSQL, TypeScript, Node.js, GitHub, Full-stack
DevReady, Denver, CO
Amazon Web Services (AWS), Google, Redis, React, PostgreSQL, TypeScript...
Test-driven Development (TDD), Scrum, Microsoft Azure, Microsoft SQL Server, C#...




Preferred Environment

Git, Visual Studio Code (VS Code), Ubuntu

The most amazing...

...projects I’ve built are an eCommerce and some mission-critical applications responsible for the registrations and timing of the most important races in Brazil.

Work Experience

Lead Software Engineer

2019 - PRESENT
DevReady, Denver, CO
  • Architected and designed an online tutoring sessions system, with video calls, virtual whiteboard, screen sharing, file sharing, and text chat.
  • Researched and compared communication platform as a service (CPaaS) providers to guide business decisions.
  • Created some proof-of-concept web apps backed by Twilio, to demonstrate the core project features, such as video calls and the virtual whiteboard.
  • Developed the project’s REST API using Noje.js, TypeScript, WebSockets, and PostgreSQL.
  • Implemented continuous integration and continuous delivery (CI/CD) using Docker and Docker Compose and Azure Pipelines.
  • Led the development team, giving directions, ensuring best practices and code quality.
Technologies: Azure, Redis, PostgreSQL, TypeScript, Node.js, GitHub, Full-stack

Senior Software Engineer

2018 - 2019
DevReady, Denver, CO
  • Designed the domain model of a complex routing optimization project.
  • Researched vehicle route optimization problem (VRP) and created a proof of concept prototype using Google OR-tools.
  • Architected and developed the project’s REST API using Node.js, TypeScript, and PostgreSQL.
  • Architected and developed a real-time system responsible for receiving millions of vehicle notifications per day. Built with socket.io and a queue backed by Redis, ensuring scalability and fast response times.
  • Implemented continuous integration and continuous delivery (CI/CD) using CircleCI and AWS Elastic Beanstalk.
  • Created more than one thousand unit and integration tests, having around 90% of test coverage.
  • Acted as the most experienced developer in the team, naturally assuming a team lead position and coordinating the work of three developers.
Technologies: Amazon Web Services (AWS), Google, Redis, React, PostgreSQL, TypeScript, Node.js, GitHub, Full-stack

Senior Software Engineer

2012 - 2018
  • Architected, designed, and developed the company’s eCommerce where runners can register themselves in races, similar to the New York Marathon, that take place in Brazil.
  • Architected, designed, and developed a mid-size application to manage internal processes, tracking the production of bib numbers tagged with RFID chips. Built with Node.js, MongoDB, GraphQL, and React.
  • Introduced TDD methodology, GitFlow, and some Scrum concepts such as sprints and daily meetings.
  • Mentored junior and mid-level developers through code reviews, explaining best practices and principles such as SOLID and DRY.
  • Identified application bottlenecks making use of profiling tools and solved them by improving database queries, implementing caching, code optimization, and more.
  • Helped redesign the financial module with multiple features and reports that brought more control and transparency to clients, becoming a key business differentiator.
  • Re-engineered the payment architecture allowing different payment platforms to be integrated seamlessly.
  • Migrated the company’s eCommerce application and database to Microsoft’s Azure Platform, improving performance, reliability, and scalability, reducing costs and simplifying the system administration.
  • Implemented automated continuous deployment, integrating Git repositories with Azure Platform, facilitating the release of new versions of web applications.
  • Implemented unit and integration tests with Jest and end-to-end tests with Cypress.
Technologies: Test-driven Development (TDD), Scrum, Microsoft Azure, Microsoft SQL Server, C#, ASP.NET, MongoDB, GraphQL, Node.js, React, GitHub, Full-stack

Software Engineer

2010 - 2012
Sercom Contact Center
  • Collaborated in the development of a new version of a workflow web application, the company’s core product.
  • Designed and built custom call center applications for the company’s clients, participating in the whole life cycle, since gathering requirements until the application deployment and maintenance.
  • Guided trainees to accomplish easy- to mid-level tasks while explaining programming concepts.
Technologies: Entity Framework, Microsoft SQL Server, ASP.NET, C#, GitHub, Full-stack

Software Engineer

2007 - 2010
ChipTiming Cronometragem
  • Designed and developed two mission-critical desktop applications replacing outdated solutions. The software collects and processes hundreds of thousands of data in real time from RFID readers used in races similar to the New York Marathon, that take place in Brazil.
  • Architected and developed a client-server desktop application used to manage runners registrations and control races kit pick-up operations, creating a whole new service provided by the company.
  • Created a brand new version of the company’s website with results and events calendar.
  • Proposed software solutions to improve internal processes.
  • Awarded Best Employee of the Year twice by the company and coworkers.
Technologies: MySQL, SQLite, Microsoft SQL Server, NHibernate, ASP.NET, Windows Presentation Foundation (WPF), Windows Forms (WinForms), C#, GitHub, Full-stack


TicketRun is an eCommerce site where runners can register themselves in races similar to the New York Marathon but takes place in Brazil.

I was responsible for the architect, design, and development of this eCommerce from scratch. It is a huge project with a multitude of functionalities, with many integrations and accessed by different roles with different permission levels.

One of the most import aspects of the project is the payment system. During the years I developed the integration with five payment gateways and had to re-engineer the system to make it adaptable to different payment methods.

Over the years, I have had the opportunity to lead some junior and mid-level developers, reviewing their code, guiding them and teaching best practices on how to write clean and maintainable code, and how to apply principles such as DRY and SOLID.

I also was responsible for planning and migrating the application and the database to Microsoft Azure platform, improving the performance, scalability, and reliability. Taking advantage of Azure integration with Bitbucket, I also implemented continuous deployment, facilitating the release of new versions of the site.


I was responsible for updating the entire company’s software arsenal. Working closely with managers, I consolidated their ideas and experiences gained over the years to architect and develop new applications with better user experience, performance, reliability, and flexibility.

One of the main challenges was to create a desktop application to run the core business of the company, responsible for process the runners’ time, classify them and generate the results in real time. The project has a considerable complexity, with many different inputs, outputs, and options to support different styles of race.

Another interesting project was a multithreaded application, with a plugin-like architecture, to communicate with a variety of RFID readers via TCP and USB ports.

I also built a registration and kit pick-up management system. A client-server application, with dynamic registration forms, designed to be extremely flexible and attend different client needs.

Those different kinds of challenges gave me a broader perspective about system architecture and had enormously improved my analytical skills, which now allows me to tackle problems in different ways and find solutions for them fast and effectively.

Sentry Transport for Winston

Open-source project. A Sentry transport for Wiston@3 using @sentry/node that allows logging context data, such as user, tags, fingerprint, and extra data.


A simple project where I showcase some of my full-stack software development skills, knowledge of best practices.

Built with Node.js and React.
2007 - 2010

Bachelor's Degree in Computer Science

São Judas Tadeu University - São Paulo, Brazil


Node.js, React, Entity Framework, Windows Forms (WinForms), jQuery


Git, Docker Compose, GitHub


ASP.NET, NestJS, NHibernate, Windows Presentation Foundation (WPF), Express.js


C#, JavaScript, TypeScript, SCSS, GraphQL


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


REST, Object-oriented Programming (OOP), Unit Testing, Functional Programming, Test-driven Development (TDD), Scrum, Database Design


Windows, Visual Studio Code (VS Code), Amazon Web Services (AWS), Docker, Ubuntu, Linux, Azure


User Interface (UI), Full-stack, TypeORM, Integration Testing, Microsoft Azure, Google, GitFlow, Data Structures

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