Patricio Diego Balenzuela, Developer in Lomas de Zamora, Buenos Aires Province, Argentina
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Patricio Diego Balenzuela

Verified Expert  in Engineering

Software Developer

Location
Lomas de Zamora, Buenos Aires Province, Argentina
Toptal Member Since
March 14, 2016

Patricio considers himself a passionate and dedicated professional and mentor who pays close attention to details and embraces theory and good practices, trying to deliver the best quality while understanding deadlines and business objectives. As a developer, he is always learning new things and technologies. As a leader, Patricio is excellent at finding his team's strengths and weaknesses and making them successful.

Portfolio

Hire Bus, LLC
TypeScript, Node.js, MySQL, Docker, Amazon Web Services (AWS), APIs...
Volvo Car
React, JavaScript, TypeScript, CSS, HTML, Responsive Web Apps, Node.js, MySQL...
Snow Owl
Cloudflare, Fauna, Amazon Web Services (AWS), Next.js, Svelte, Material UI...

Experience

Availability

Part-time

Preferred Environment

React, Node.js, JavaScript, TypeScript

The most amazing...

...project I've worked on allowed my newly created team to deliver a critical feature in record time, turning the company into the best in the market.

Work Experience

Agile Coach | Solutions Architect

2023 - 2024
Hire Bus, LLC
  • Designed and implemented the architecture to have UI E2E tests using Playwright.
  • Defined CI/CD pipelines based on specific GitHub Actions.
  • Coached the development team to implement Agile methodologies properly, including Poker game to size stories, "walk the board" for daily stand-ups, etc.
  • Introduced contract tests to validate interactions with external systems. Used contract tests validate that the System is properly interactive with external ones.
  • Enabled repository pattern to allow E2E repository testing.
  • Introduced different unit test patterns in both the back and front end to make components and modules easier to maintain.
  • Refactored existing API into a well-defined RESTful API. The original API did not follow RESTful best practices.
  • Removed, replaced, and upgraded numerous dependencies in favor of a core set of well-maintained ones. The project included many different packages that served similar purposes. The code was refactored to use just one per aspect.
Technologies: TypeScript, Node.js, MySQL, Docker, Amazon Web Services (AWS), APIs, Software Architecture, Test-driven Development (TDD), OAuth, Playwright, AWS Lambda, React, API Integration, API Testing, REST APIs, Storybook, Next.js, Tailwind CSS, Serverless, Automation, Large Language Models (LLMs), Artificial Intelligence (AI), Prompt Engineering, Vercel

Front-end Developer

2022 - 2023
Volvo Car
  • Worked on feature discovery, analysis, design, and implementation.
  • Managed performance tuning of UI components and network calls.
  • Moved away from functional domain design in favor of domain-driven design.
  • Fostered team self-awareness and discovery by implementing auto-regulated retrospective meetings.
  • Created test automation by designing a testing pyramid covering the whole system. This included API tests, UI E2E tests, repository tests, etc.
  • Utilized GitHub discussions for feature and technical discussions.
  • Completed the implementation of connected-retail-ui npm UI library, a React library that provided basic UI components.
Technologies: React, JavaScript, TypeScript, CSS, HTML, Responsive Web Apps, Node.js, MySQL, Microservices, Amazon Web Services (AWS), GraphQL, React Apollo, Apollo, Redis, REST, RTL, Kubernetes, Playbright, UI Components, Web Usability, Jest, Test-driven Development (TDD), Microservices Architecture, Automation

Front-end Developer

2022 - 2022
Snow Owl
  • Assisted in completing the alpha version. I was in charge of the beta phase that was implemented in React.
  • Provided to the alpha version a responsive design suitable for desktop and mobile.
  • Leveraged the usage of components in a way that can be easily migrated from the current Svelte application into the new React one.
Technologies: Cloudflare, Fauna, Amazon Web Services (AWS), Next.js, Svelte, Material UI, Tailwind CSS, Node.js, React, TypeScript, REST, User Experience (UX), User Interface (UI), Content Delivery Networks (CDN), UI Components, Web Usability, Jest, Test-driven Development (TDD), Automation

Development Lead

2020 - 2021
Tatango
  • Acted as a lead developer, made technical decisions, and interacted with the business to define requirements and create user stories.
  • Conducted the different scrum ceremonies, guided and mentored the team, unblocking problems, and managed the Sprint board.
  • Helped the business achieve its goals by discovering what tools it needed and applying continuous integration and incremental feature enhancements.
  • Designed and led the SMS and MMS enhancements project, the core feature of the company, delivering right on time and almost without any errors.
  • Designed and implemented database tests, including them as part of the CI/CD pipeline.
Technologies: React, Node.js, TypeScript, Amazon Web Services (AWS), Docker, APIs, Storybook, PostgreSQL, User Experience (UX), User Interface (UI), Content Delivery Networks (CDN), Full-stack, Serverless, AWS Lambda, UI Components, Design Systems, Web Usability, Tailwind CSS, Jest, Test-driven Development (TDD), Automation

Development Lead

2020 - 2021
Interview Stream
  • Designed and implemented microservices with Python.
  • Developed team best practices, a collaborative spirit, and continuous team improvement practices.
  • Applied Agile methodologies to discover the right way to build the right product. Used trunk-based development and deployed minimal incremental features by the end of each sprint.
Technologies: Docker, GitHub, Amazon Web Services (AWS), Kubernetes, Datadog, Bugsnag, Python, React, REST, GraphQL, TypeScript, APIs, REST APIs, API Testing, E2E Testing, Integration Testing, PostgreSQL, User Interface (UI), Full-stack, PHP, UI Components, Design Systems, API Integration, Jest, Test-driven Development (TDD), Microservices, Automation, Redux

Development Lead

2019 - 2020
RAD Development
  • Redefined the architecture of the Axis web application.
  • Implemented a React single-page application with Material-UI and TypeScript.
  • Led the development team, managing priorities and writing requirements.
  • Configured and tuned Webpack to support ES features.
  • Supported old components while migrating the application to a new design.
Technologies: TypeScript, React, JavaScript, APIs, Material UI, Node.js, User Experience (UX), User Interface (UI), Full-stack, UI Components, Design Systems, Jest, Test-driven Development (TDD), Automation, Redux

Lead Developer

2018 - 2019
Nuvem Nine Consulting
  • Defined the system architecture, including the API and web application.
  • Defined architecture changes to make the system support multiple languages.
  • Designed the architecture to upgrade from RavenDB 3 to 4.
  • Designed architecture to change the queue system from MSMQ to Rabbit MQ.
  • Converted a Vanilla JS application to TypeScript.
Technologies: RavenDB, React, Node.js, JavaScript, .NET, TypeScript, User Interface (UI), Full-stack, Design Systems, Jest, Test-driven Development (TDD), Automation

Software Architect

2015 - 2018
Tradehelm
  • Led and implemented the Tele Insurance IVR application project.
  • Contributed to the architecture team defining the microservices ecosystem and web applications.
  • Trained the team in important concepts like TDD, BDD, and DDD.
  • Built a JavaScript framework designed to support front- and back-end validations.
  • Architected tests for the project, including unit, integration, repository, contract, and automated UI tests.
Technologies: React, Node.js, JavaScript, .NET, HIPAA Compliance, User Interface (UI), Full-stack, Design Systems, API Integration, Jest, Test-driven Development (TDD), Automation

Software Engineer

2014 - 2015
MercadoLibre
  • Developed and maintained the payments subsystem, one of the site's core features.
  • Provided the option to split the payment into two different payment methods.
  • Introduced automated test techniques into the project.
Technologies: Groovy, Grails, JavaScript, User Interface (UI), Full-stack, Jest, Test-driven Development (TDD)

Architect | Full-stack Developer

2011 - 2014
BVision
  • Consulted on architecture to design new software to achieve higher maintainability and performance.
  • Led the local team for the Dynamic Signal US startup project.
  • Configured continuous integration using TeamCity.
  • Proved uncoupled design portability when the client decided to change the DB provider to be used near the end of the project. The problem was solved in less than a week.
  • Defined architectural standards for new .NET projects in the company.
Technologies: Node.js, JavaScript, .NET, CSS, Front-end, PostgreSQL, MySQL, User Interface (UI), Full-stack, Test-driven Development (TDD)

.NET Consultant | System Analysis Pro

2008 - 2011
Verizon
  • Developed mobile applications for laptops and handheld devices to assist technicians with their work.
  • Created a web map aid in order to manage technicians' work areas, making its maintenance and visualization more intuitive.
  • Designed a common rule manager to keep consistency among mobile and centralized applications. Quality, consistency, and cohesion of the code were achieved.
  • Designed and implemented an ORM framework to automate query generation.
  • Built an auto-dispatch engine, which reduced manual dispatch to 25%.
Technologies: ASP.NET, C#, Desktop App Development, Mobile Apps, JavaScript, Microsoft SQL Server, Full-stack, .NET, Test-driven Development (TDD)

Development Lead | Architect

2007 - 2008
Ypf
  • Developed a JavaScript validation toolkit that parsed MVC validations to automatically generate the equivalent JavaScript ones.
  • Improved the performance of the "Imagen Corporativa" System, fixing database indexes, relations, queries, and hibernate maps.
  • Built an internationalization framework, allowing web apps to be displayed in different languages using a simple configuration process.
  • Monitored the batch tasks engine using web services with a hot plug of new components.
  • Advised other project leaders on technical matters.
Technologies: ASP.NET, C#, JavaScript, jQuery, CSS, Microsoft SQL Server, Web Services, Full-stack, .NET

Analyst and Developer

2006 - 2007
Cubika
  • Implemented the remote functionality to support access to remote objects.
  • Developed the dashboard application with the Infragistics components that enabled quick access to problems for technicians.
  • Enabled SQL queries performance enhancements to make queries run in less than a second.
Technologies: ASP.NET, C#, Remoting, Microsoft SQL Server, Full-stack

.NET Developer

2003 - 2006
SouthWorks
  • Designed a database migration from the old system to the new one.
  • Contributed to the website design for the landing page and dashboard.
  • Handled the migration design from the older .NET 1.1 to Framework 2.0.
Technologies: ASP.NET, Microsoft SQL Server, HTML, CSS, Full-stack

Resource Manager

Acted as a consultant and senior developer and designed, developed, and maintained the Resource Manager suite of products, including web, desktop, and mobile applications. I coordinated resources in the process of developing new requirements as well as designing the solution for them. I also created and developed toolkits and frameworks.

The primary purpose of the Resource Manager is to dispatch technicians to solve client issues and Verizon network problems.

Serbiznet

Architecture consultant.

Serbiznet is a worldwide client whose business is related to the installation, consulting, layout design, maintenance, etc., of service stations for fuel. My responsibilities include the assessment, improvement of the current system architectures, and designing and developing the new systems.

CompData

CompData provides lawyers in California a platform to interact with the Department of Industrial Relations. The project aims to implement a new web application to replace the current desktop client. The technology stack includes a React application running in Node.js and an API based on GraphQL running in Node.js.

La Postiva Seguros

https://www.lapositiva.com.pe/
Built a website for a client based on MVC 4, JavaScript, and .NET Framework 4.5. The project's main goal was to maintain the lifecycle of claims related to health care. The team was composed of two developers, one business analyst, and one tester.

Flow

ROLE: Developer.

A CMS website is based on providing advertising services. Two sites were maintained, including the user portal and manager portal.

The technologies used include Node.js, MongoDB, and Keystone.js. Unit tests ensured quality.

Disney Brief

Architect and senior developer.

A website was built to provide a way of handling documents to design and define products and campaigns for the Disney Company. Different approaches were applied to get the best quality (unit testing, integrations, UI tests, repository, and service patterns), all handled using continuous integration (TeamCity).

Dynamic Signal

https://dynamicsignal.com/
ROLE: Technical leader and senior developer.

An offshore company in San Francisco hired a Buenos Aires team to help develop this application. This application is a marketing platform that uses different social networks (Twitter, Facebook, Tumbler, Blogger, YouTube, etc.) to provide word-of-mouth marketing.

Pharos Innovations

Pharos is a company located in Chicago dedicated to providing healthcare engagement programs to patients with chronic conditions. These programs help them take care of their health and save on expenses.

The old platform was redesigned. The system's architecture includes at least seven REST APIs that talk to each other and provide services to React web applications, IVR systems, and native phone apps.

To obtain the highest levels of quality, the system is implemented using many stacks of automated tests, including unit, integration, repository, contract, integration between APIs, and load and automated UI tests, to quote a few.

Techniques applied to the development process include TDD, DDD, dependency injection, and design patterns. The deployment is automated using Jenkins as a continuous integration platform.

Some other miscellaneous examples of used tools are:
• Sonar for static analysis of code quality
• Stackify to track the website's performance
• Bugsnag to track the website's errors
• RabbitMQ as a queue services platform
• Node.js website using ES6, Webpack, Jest, and SCSS

Bettween

Bettween is a website that pulls tweets from Twitter to discover conversations between users plus other functionalities.

Enhanced the existing website's performance, redesigned its architecture, and significantly improved response time.

CME Group

The current project goal is to create a front-end to make information about the volatility of stocks available to financial consultants of CME. My responsibilities include architecture and leading the implementation of a new SPA based on Node.js and React supported by a set of microservices based on .NET.
The architecture definition includes different layers of automated tests, including unit, integration, etc., and the front-end tests, including unit and component tests.

CME Volatility Project

The current project goal is to create a front end to make information about the volatility of stocks available to financial consultants of CME. My responsibilities include the architecture and implementation of a new SPA (based on Node.js and React) supported by a set of microservices (based on .NET).
The architecture definition includes different layers of automated tests (unit, integration, etc.) and front-end tests, including unit and component tests.

Gateway

https://www.gatewaypetmemorial.com/
Gateway is a pet aftercare company. The system manages the complete cremation process, letting the pet owner choose different services and products, and is composed of three other websites and two mobile apps.

The technology stack includes a React front end, .NET Core REST API, Xamarin, and a RavenDB document database.

AMI Attachments

http://www.amiattachments.com/
AMI is a company that sells attachments for excavators, loaders, etc. The process of quoting and creating orders is currently made by hand. A new web system is being designed and implemented to make this process online. The technology stack includes a React front-end, .NET REST API, and a RavenDB document database

SnowOwl Project

SnowOwl is a network traffic management platform that monitors, routes, and transforms all network traffic to your domains. Or, in simpler terms, it makes it simple and quick to run the DevOps yourself.

The product is currently in the development phase targeting an Alpha version very soon. The web application is implemented in Svelte using Svelte Kit with Material UI components.

While helping to finish the Alpha version, I'm responsible for the Beta phase implemented in React. The new stack is a Next.js app using TypeScript and Tailwind components.

Technologies used include different Cloudflare technologies (Pages, Workers, KV, etc.), Fauna DB, and AWS.

InterviewStream Project

https://interviewstream.com/
InterviewStream is an online platform with tools targeted to simplify the hiring process.

The platform is a monolith with a complicated architecture, suffering from performance issues, and many of the tools have been disconnected from each other. The current goal is to reimagine and modernize the product, integrate all the tools, deprecate the features that are not in use or are not relevant, and create the right product correctly.

The new architecture design includes a set of microservices developed using Python, which is implemented as REST or GraphQL services. The front-end design is a set of micro front ends developed using- React/TypeScript.

The platform runs Docker containers orchestrated by Kubernetes and is hosted in AWS. Datadog and errors by Bugsnag track performance.

Continuous integration is enforced by unit, DB, integration (feature API tests), contract, and UI functional tests. UI components are tested as well.

Using trunk-based development, minimal incremental features are deployed by the end of each sprint, and bigger and more complex features are enabled using feature toggles.

Axis Project

Axis is an application targeted to help the construction industry to plan and execute their projects. It helps industries find the right resources while managing payments, contractors, and third-party companies.

As part of a re-branding strategy, the outdated web applications are being re-architected to target a React SPA application implemented with React, MUI, TypeScript, and Node.js.

Tatango

https://www.tatango.com/
Tatango is America's top political SMS marketing software.

As a development lead, I made technical decisions and interacted with businesses to define requirements and create user stories. I conducted different scrum ceremonies, guided and mentored the team, unblocked problems, and managed the sprint board.

Further, I participated in the architectural design and discussions. Also, I helped businesses achieve their goals by discovering the tools they need and applying continuous integration and incremental feature enhancements.

I used React, Node.js, TypeScript, AWS, and Docker technologies.

Birdseye

https://uswest2.birdseye.luxe.com/
Birdseye is a system that enables clients to schedule services on their Volvo cars (on-site and at home), schedule test drives, and schedule new vehicle handover. It provides services to customers, dealerships, and other systems, providing an API so external services interact with it. Users, including clients, dealerships, and technicians, can interact with it through a web interface and mobile applications.

As a staff front-end engineer, I designed, implemented, and led different initiatives, including:
• Feature discovery, design, and implementation
• Performance tuning
• Domain-driven design re-architecture
• Team self-awareness and discovery by implementing auto-regulated retrospective meetings
• Test automation by designing a testing pyramid
• GitHub discussions for feature and technical discussions
• Connected-retail-ui npm UI library

Hirebus

https://hirebus.com/
Using different AI tools, Hirebus helps companies find the best professionals they might need.
As an architect, I helped them improve their processes by defining a better architecture and helped the development team apply Agile methodologies.

My achievements include the following:
• Defined Testing Pyramid
- Designed and implemented architecture to have UI E2E tests using Playwright.
- Introduced contract tests to validate interactions with external systems.
- Enabled repository pattern to allow E2E repository testing.
- Introduced different unit test patterns in both back and front ends to make components and modules easier to maintain.
- Oversaw CI/CD.
- The pipeline was defined based on GitHub Actions.
• Architecture Assessment and Improvement
- Implemented Sentry, including session replay.
- Turned existing API into a well-defined RESTful API.
- Removed, replaced, and upgraded a lot of dependencies in favor of a core set of well-maintained ones.
- Defined an architecture for the web and API project.
- Identified different vulnerabilities.
- Identified performance and maintainability issues.
• Agile Methodology Implementation
- Coached the development team to implement Agile methodologies properly.
2010 - 2011

Software Engineering Specialist's Degree in Computer Engineering

Pontificia Universidad Católica Argentina 'Santa María de los Buenos Aires' - Buenos Aires, Argentina

1999 - 2007

Engineer's (Corresponds to a Six-year University Program) Degree in Information Systems

University of Buenos Aires - Buenos Aires, Argentina

DECEMBER 2014 - PRESENT

MongoDB for Node.js Developers

MongoDB

Libraries/APIs

React Router, React, jQuery, Node.js, Entity Framework, Backbone.js, REST APIs, Playwright

Tools

Microsoft Visual Studio, ReSharper, Toad, LINQ to SQL, Subversion (SVN), GitHub, Jira, RabbitMQ, Git, Eclipse IDE, IntelliJ IDEA, Bugsnag, Sonar, Webpack, React Apollo

Frameworks

.NET, Redux, ASP.NET, ASP.NET Web API, ASP.NET MVC, Next.js, Jest, Bootstrap, SpecFlow, .NET Core, Entity Framework Core, Material UI, Tailwind CSS, AngularJS, Angular, Svelte, Electron, Express.js, Grails

Languages

GraphQL, CSS, HTML, HTML5, CSS3, SQL, JavaScript, C#, TypeScript, Less, SCSS, Sass, XML, UML, Python, Smalltalk, C, Java, C++, Groovy, PHP

Paradigms

REST, Reflective Programming, Event-driven Programming, Functional Programming, Concurrent Programming, Object-oriented Design (OOD), Distributed Programming, Domain-driven Development, Model View ViewModel (MVVM), Unit Testing, Scrum, Dependency Injection, Test-driven Development (TDD), Model View Controller (MVC), Microservices, Automation, Distributed Computing, Continuous Integration (CI), Aspect-oriented Programming, Parallel Computing, Design Patterns, Desktop App Development, E2E Testing, HIPAA Compliance, Microservices Architecture

Platforms

Windows, Oracle, Amazon Web Services (AWS), AWS Lambda, Vercel, Linux, Visual Studio Code (VS Code), Docker, Kubernetes, KeystoneJS, Xamarin, AWS IoT

Storage

JSON, Microsoft SQL Server, MySQL, MongoDB, RavenDB, Datadog, PostgreSQL, Redis

Other

Lambda Functions, Ajax, Reflection, IoC, Integration Testing, Multithreading, APIs, Front-end Development, Responsive Web Apps, Full-stack, UI Components, Design Systems, API Integration, Regular Expressions, Windows Services, Web Services, UI Testing, API Testing, User Experience (UX), User Interface (UI), Content Delivery Networks (CDN), Serverless, Web Usability, State Machines, Unix Shell Scripting, Cloudflare, Fauna, Domain-driven Design (DDD), CI/CD Pipelines, Front-end, Remoting, Mobile Apps, Software, Information Systems, DocumentDB, Storybook, RTL, Apollo, Playbright, Software Architecture, OAuth, Large Language Models (LLMs), Artificial Intelligence (AI), Prompt Engineering

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