Sergio Antonio Milici, Developer in Buenos Aires, Argentina
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Sergio Antonio Milici

Verified Expert  in Engineering

Full-stack Developer

Location
Buenos Aires, Argentina
Toptal Member Since
May 20, 2014

Sergio is a software engineer with a talent for developing scalable and efficient solutions for complex problems. He has a comprehensive understanding of design processes with experience in all the design stages of a product, including research, development, scalability, and testing.

Portfolio

Ofinno LLC
CSS, CI/CD Pipelines, Node.js, Next.js, Full-stack, Figma, Product Management...
Veza
React, CSS, JavaScript, HTML, APIs, REST APIs, CSS-in-JS, Cypress, Jest, Docker...
TalentWall
Sass, TypeScript, Angular, CSS, JavaScript, HTML, NgRx, NgRx/store, Redux, RxJS...

Experience

Availability

Part-time

Preferred Environment

Web, iOS, Android, Ionic, Angular, React, Node.js, CSS, JavaScript, HTML, TypeScript, Full-stack, APIs, Mobile, Cross-platform, Full-stack Development, Mobile Apps, Minimum Viable Product (MVP), GitHub, Amazon Web Services (AWS), Web Development, MERN Stack, API Integration, Front-end Development, Tailwind CSS, Web UX, Ant Design, Amazon DynamoDB, Git, Web Applications, Unit Testing, REST, Single Sign-on (SSO), Responsive Layout, SCSS, UI Components, GraphQL, UI Testing, SQL, JSON Web Tokens (JWT), OAuth 2, UI Libraries, Component Libraries, Front-end Architecture, Software Engineering, Web API, JavaScript 6, Firebase Realtime Database, Leadership, Agile, Consulting, Figma, Microsoft Teams, Slack App, JSON, Algorithms, CI/CD Pipelines, Websites, WebSockets, Forms, Third-party APIs, Third-party Libraries, Google Maps, Design Systems, Capacitor, Google Analytics, Hybrid Apps, Object-oriented Design (OOD), Mobile Applications, App Store, Google Play Console, Mapbox API

The most amazing...

...project I've created is a distributed system to control all software and hardware changes on every machine in a network.

Work Experience

React/Full-stack Developer

2023 - 2023
Ofinno LLC
  • Designed and implemented the project architecture, from selecting the main framework and 3rd-party libraries to defining the app state.
  • Implemented the entire design system from scratch with Storybook.
  • Analyzed requirements and managed implementation with other team members.
  • Implemented and tested 100% of project pages and features.
Technologies: CSS, CI/CD Pipelines, Node.js, Next.js, Full-stack, Figma, Product Management, Tailwind CSS, Docker, PostgreSQL, Python, Design Systems, Storybook, Third-party APIs, Redux, JavaScript, Google Analytics, Hybrid Apps, Object-oriented Design (OOD), Web Performance Optimization (WPO)

React Developer

2020 - 2022
Veza
  • Implemented the 1st successful MVP of the company to get funding.
  • Set up, designed, and implemented the front-end official project; also supported the design system implementation and project architecture.
  • Led a UI project in cooperation with other Toptal employees to create the current front-end project used by all company clients.
  • Set up and maintained GitHub Actions as continuous integration (CI) for running the build process on every pull request, including setting up the entire test environment for running unit tests, end-to-end tests, error reporting, and builds.
Technologies: React, CSS, JavaScript, HTML, APIs, REST APIs, CSS-in-JS, Cypress, Jest, Docker, TypeScript, Next.js, AWS Lambda, GitHub, Amazon Web Services (AWS), Styled-components, Web Development, Responsive Web Apps, Storybook, API Integration, Front-end Development, Ant Design, Git, Web Applications, Unit Testing, REST, Single Sign-on (SSO), Responsive Layout, SCSS, UI Components, UI Testing, SQL, JSON Web Tokens (JWT), OAuth 2, UI Libraries, Component Libraries, Front-end Architecture, Software Engineering, Web API, JavaScript 6, Leadership, Agile, Consulting, MobX, User Interface (UI), User Experience (UX), Web Design, Web, Figma, JSON, Algorithms, CI/CD Pipelines, Design, Websites, Forms, Third-party APIs, Third-party Libraries, Design Systems, Google Analytics, Hybrid Apps, Object-oriented Design (OOD), Web Performance Optimization (WPO)

Senior Front-end Software Engineer

2020 - 2021
TalentWall
  • Created a drag-and-drop grid system to build custom dashboards from a set of resizable charts allowing the user to modify the position on the dashboard.
  • Improved user navigation experience reducing page load by 40%.
  • Designed multiple UI filters to be used across apps.
  • Improved app responsiveness by fixing internal algorithms to handle +5000 jobs in the UI.
Technologies: Sass, TypeScript, Angular, CSS, JavaScript, HTML, NgRx, NgRx/store, Redux, RxJS, Functional Reactive Programming, APIs, Mobile Apps, Test-driven Development (TDD), GitHub, Web Development, Responsive Web Apps, AG Grid, API Integration, Front-end Development, Git, Web Applications, Unit Testing, CSV, REST, Single Sign-on (SSO), Responsive Layout, SCSS, UI Components, UI Testing, SQL, JSON Web Tokens (JWT), OAuth 2, UI Libraries, Front-end Architecture, Software Engineering, Web API, JavaScript 6, Firebase Realtime Database, Leadership, Agile, Consulting, User Interface (UI), User Experience (UX), Web, Figma, JSON, Algorithms, Design, WebSockets, Forms, Third-party APIs, Third-party Libraries, Design Systems, Google Analytics, Hybrid Apps, Object-oriented Design (OOD), Web Performance Optimization (WPO)

Senior Full-stack Software Engineer

2019 - 2019
Social Camping
  • Set up the back end with Node.js, Express, and Firestore to manage the user's assets.
  • Integrated Firebase Auth to allow users to log in with Google, Facebook, and email and password.
  • Created the front-end project with Angular and Bootstrap for implementing a CRUD to allow users to manage their camping assets.
  • Implemented Figma design to create reusable UI system components.
Technologies: Bootstrap, Firebase, Angular, Express.js, Node.js, CSS, JavaScript, HTML, TypeScript, Redux, Full-stack, APIs, Full-stack Development, Ionic, GitHub, Progressive Web Applications (PWA), Web Development, Responsive Web Apps, Storybook, API Integration, Front-end Development, Next.js, Tailwind CSS, Git, Web Applications, Unit Testing, CSV, Electron, REST, Single Sign-on (SSO), Responsive Layout, SCSS, Material UI, UI Components, GraphQL, UI Testing, SQL, JSON Web Tokens (JWT), Auth0, OAuth 2, UI Libraries, Front-end Architecture, PWA, Software Engineering, Web API, JavaScript 6, Firebase Realtime Database, Agile, User Experience (UX), Web, Figma, JSON, Design, Websites, WebSockets, Forms, Canvas, Third-party APIs, Third-party Libraries, Design Systems, Google Analytics, Hybrid Apps, Object-oriented Design (OOD), Mobile Applications, Mapbox API

Senior Software Enginner

2016 - 2018
Qwill
  • Built the first release product of Qwil's web application in AngularJS.
  • Migrated and rebuilt the web application in the React ecosystem.
  • Created the UI components to build out Qwil's design system with the lead product designer.
  • Reduced 90% of web app load time, implementing lazy load components.
  • Set up and implemented a standardized E2E testing platform with Docker and Nightwatch for multiple environments to ensure software release quality.
  • Implemented unit testing to improve the development process that was adopted company-wide, which resulted in reducing bugs by 50%.
Technologies: Enzyme, Jest, Sass, Babel, Webpack, Flow, React, CSS, JavaScript, Node.js, HTML, TypeScript, Angular, Redux, RxJS, Architecture, Full-stack, APIs, Mobile, Cross-platform, Financial APIs, Mobile Apps, Minimum Viable Product (MVP), Test-driven Development (TDD), AWS Lambda, GitHub, Progressive Web Applications (PWA), Responsive Web Apps, Storybook, API Integration, Front-end Development, Tailwind CSS, Git, Web Applications, Unit Testing, CSV, REST, Responsive Layout, SCSS, UI Components, GraphQL, UI Testing, SQL, JSON Web Tokens (JWT), OAuth 2, UI Libraries, Front-end Architecture, Software Engineering, Web API, JavaScript 6, Agile, GitLab, Consulting, User Interface (UI), User Experience (UX), Web Design, Web, Figma, JSON, Algorithms, CI/CD Pipelines, Websites, WebSockets, Forms, Third-party APIs, Third-party Libraries, Design Systems, Capacitor, Google Analytics, Hybrid Apps, Object-oriented Design (OOD), Mobile Applications, Web Performance Optimization (WPO)

Mobile Engineer

2015 - 2015
Hollaback!
  • Created a hybrid HTML5 mobile app from scratch for Android and iOS using Ionic.
  • Designed and implemented business logic in JavaScript following design patterns and best practices.
  • Deployed builds to production for Android and iOS using TestFlight and Google Play.
  • Integrated native plugins like geolocation, contacts, and keyboard.
  • Integrated Facebook native login and Google Maps API.
Technologies: JavaScript, Sass, Ionic, AngularJS, CSS, HTML, Angular, Redux, Full-stack, APIs, Mobile, Cross-platform, Full-stack Development, Mobile Apps, Minimum Viable Product (MVP), GitHub, API Integration, Front-end Development, Git, Web Applications, Unit Testing, REST, Single Sign-on (SSO), Responsive Layout, SCSS, UI Components, UI Testing, JSON Web Tokens (JWT), Auth0, OAuth 2, UI Libraries, Software Engineering, Web API, JavaScript 6, Firebase Realtime Database, Web, JSON, Websites, Forms, Third-party APIs, Third-party Libraries, Google Maps, Design Systems, Object-oriented Design (OOD), Mobile Applications, App Store, Web Performance Optimization (WPO)

Front-end Software Engineer

2015 - 2015
Kimono (via Topta)
  • Redesigned chat workflow for sending and receiving messages.
  • Created the mobile version of the app using the Ionic Framework.
  • Refactored and designed the OOP model to be maintainable.
  • Implemented Algolia search API to show custom and fast results.
  • Improved performance of startup of the mobile version and UX.
Technologies: JavaScript, CSS3, HTML5, iOS, Android, Cordova, Ionic, AngularJS, Node.js, HTML, TypeScript, Angular, CSS, APIs, Minimum Viable Product (MVP), GitHub, Web Development, API Integration, Front-end Development, Git, Web Applications, Unit Testing, Single Sign-on (SSO), Responsive Layout, UI Components, SQL, Software Engineering, Web API, Web, JSON, Forms, Third-party APIs, Google Maps, Design Systems, Hybrid Apps, Object-oriented Design (OOD), Mobile Applications

Java DevOps Consultant

2014 - 2014
L2
  • Converted five existing Java projects to Maven projects.
  • Designed and implemented a configuration module to support multiple environments using Typesafe Config.
  • Set up automatic builds on Jenkins and integrate it with GitHub.
Technologies: Jenkins, Apache Maven, Java, HTML, JavaScript, CSS, APIs, GitHub, Web Development, API Integration, Front-end Development, Git, Web Applications, Unit Testing, REST, SQL, OAuth 2, Software Engineering, JavaScript 6, Web, JSON, Forms, Third-party APIs, Third-party Libraries, Design Systems, Hybrid Apps, Object-oriented Design (OOD)

Software Engineer

2012 - 2014
50Cubes
  • Created back-end server for an ad-targeting system for Facebook games.
  • Developed a JavaScript library to serve ads based on game states.
  • Designed a real-time metric system on HTML5 for showing user conversions.
  • Created a Java back-end server for a Space Pirates game. Integrated it with Android and Facebook.
  • Managed AWS to support all systems, including handling databases, fail-over, and performance.
Technologies: Redis, MySQL, JavaScript, Spring, Jasmine, PHPUnit, JUnit, PHP, Python, Java, Node.js, HTML, Angular, React, Redux, Architecture, CSS, Full-stack, APIs, Full-stack Development, Mobile Apps, GitHub, Amazon Web Services (AWS), Web Development, API Integration, Front-end Development, Git, Web Applications, Unit Testing, REST, Single Sign-on (SSO), SQL, JSON Web Tokens (JWT), OAuth 2, Software Engineering, Web API, JavaScript 6, Web, JSON, WebSockets, Forms, Third-party APIs, Third-party Libraries, Design Systems, Hybrid Apps, Object-oriented Design (OOD), Web Performance Optimization (WPO)

Software Engineering Tech Lead

2009 - 2012
InvGate
  • Created a multi-platform client-server application to control hardware and software changes over the whole network.
  • Developed a multi-platform client application in C++.
  • Implemented high concurrency to handle all changes on thousands of computers.
  • Managed the team and development to deliver new features.
  • Made the back-end to scale and processed vast amounts of data.
Technologies: Java, PHPUnit, Jenkins, Memcached, MySQL, HTML5, PHP, C++, HTML, CSS, Full-stack, APIs, Cross-platform, Full-stack Development, Minimum Viable Product (MVP), Test-driven Development (TDD), GitHub, Web Development, API Integration, Front-end Development, Git, Web Applications, Unit Testing, REST, SCSS, SQL, JSON Web Tokens (JWT), OAuth 2, Software Engineering, Web API, JavaScript 6, Web, JSON, Forms, Third-party Libraries, Design Systems, JavaScript, Hybrid Apps, Object-oriented Design (OOD)

C++ Developer

2006 - 2009
JDB
  • Designed a stock system to control all company assets.
  • Designed and implemented an MFC UI application from scratch.
  • Analyzed and designed MySQL schema for handling store and sales.
  • Created an installer and deployment tool for control updates.
  • Designed and implemented the migration of the store system to a web platform.
Technologies: Web, Microsoft Foundation Class (MFC) Library, Microsoft Foundation Classes (MFC), MySQL, C++, HTML, CSS, Full-stack, APIs, Full-stack Development, Test-driven Development (TDD), GitHub, Web Development, API Integration, Git, Web Applications, Unit Testing, REST, SQL, Software Engineering, Web API, Third-party APIs, Third-party Libraries, Object-oriented Design (OOD)

InvGate Assets

http://www.invgate.com/es/assets/
Assets is a suite of intelligent solutions to manage change and maximize the use of resources and make informed IT decisions.
I designed it from the very start, including creating and deploying software and handling metering, inventory, and change management modules.

Space Pirates

Space Pirates is a mobile game for Android and iOS built with Unity3D. I designed the back-end server to handle thousands of concurrent users, using Netty and Spring.

BEE

BEE is an online ad server designed specifically for 50Cubes' games. It was custom built to allow us to flexibly optimize the ads being served in our various games.
It was made on PHP, MySQL, Redis, HTML5, JavaScript, and Python.

Hollaback!

iOS: https://itunes.apple.com/us/app/hollaback!/id379866261?mt=8

Restaurant Credits

Restaurant Credits is a web project I created for a restaurant to manage people and the credits external sellers have to consume in the restaurant.
It includes features such as a dashboard for monthly reports and an entire history of the number of visitors and their credits.

If interested, please request a demo account.
2005 - 2012

Master of Engineering Degree in Information Systems Engineering

National Technological University - Buenos Aires, Argentina

Libraries/APIs

React, RxJS, NgRx, Google Maps, Facebook API, REST APIs, Web API, Node.js, MobX, Mapbox API, Microsoft Foundation Class (MFC) Library, Socket.IO, X (formerly Twitter) API, YouTube API, jQuery, NgRx/store, Firebase Web SDK, AG Grid, Backbone.js, Microsoft Foundation Classes (MFC)

Tools

Capacitor, Apache Maven, Webpack 4, SAP Hybris, GitHub, Webpack, Babel, Grunt, Karma, NPM, Google Analytics, Git, Flow, Auth0, GitLab, Canvas, Jenkins, Amazon CloudFront CDN, Subversion (SVN), Figma, Microsoft Teams

Frameworks

Next.js, Angular, Redux, Jasmine, Ionic, AngularJS, Tailwind CSS, Ant Design, JSON Web Tokens (JWT), Selenium, Bootstrap, Express.js, Jest, Electron, Material UI, OAuth 2, PHPUnit, JUnit, Spring, Cypress

Languages

HTML, CSS3, TypeScript, ES7, Sass, ECMAScript (ES6), HTML5, JavaScript, SQL, GraphQL, CSS, SCSS, JavaScript 6, PHP, Xtend, Java, C++, Python, C

Paradigms

Test-driven Development (TDD), Object-oriented Design (OOD), Cross-platform, Unit Testing, REST, Functional Reactive Programming, Model View ViewModel (MVVM), Model View Controller (MVC), Web Performance Optimization (WPO), Responsive Layout, Agile, Reactive Programming

Platforms

Web, Mobile, MacOS, Firebase, Windows, Linux, Amazon Web Services (AWS), Android, iOS, Docker, AWS Lambda

Storage

NoSQL, Firebase Realtime Database, JSON, MongoDB, Redis, MySQL, Memcached, Microsoft SQL Server, Amazon DynamoDB, PostgreSQL

Industry Expertise

Web Design

Other

Freelancing, Single-page Applications (SPA), Cordova, Hybrid Apps, Front-end Development, Progressive Web Applications (PWA), Front-end, Full-stack, APIs, Mobile Apps, Styled-components, Web Development, API Integration, Web Applications, CSV, Single Sign-on (SSO), UI Components, UI Testing, UI Libraries, Component Libraries, Front-end Architecture, Software Engineering, Websites, Forms, Third-party APIs, Third-party Libraries, Design Systems, Mobile Applications, SaaS, System Administration, Open Source, Architecture, Apps, Web Components, Enzyme, Full-stack Development, Minimum Viable Product (MVP), Responsive Web Apps, Storybook, MERN Stack, Chrome Extensions, Vite, PWA, Leadership, Consulting, Slack App, Algorithms, CI/CD Pipelines, WebSockets, App Store, Google Play Console, Financial APIs, CSS-in-JS, Firebase Hosting, Web UX, User Interface (UI), User Experience (UX), Design, Product Management, Facebook Games, Ionic Appflow

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