Mauro Lewinzon, Developer in Buenos Aires, Argentina
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Mauro Lewinzon

Verified Expert  in Engineering

Full-stack Developer

Buenos Aires, Argentina

Toptal member since November 22, 2019

Expertise
Full-stackBack-end DevelopersWeb DevelopmentAPIDatabaseMySQLSQLPHPJavaScriptReact.jsREST API
Bio

With his 19 years in web development, Mauro has worked in retail, leisure, payments, finance, crypto, and entertainment industries. He has turned many ideas into working products as a full-stack developer and a team leader. He always aims to improve productivity and optimize products and processes. He has reduced AWS costs by 90%. Mauro builds the right architecture for the product, from infrastructure to development.

Portfolio

Union Digital Inc
Node.js, NestJS, React, React Native, Chakra UI, REST APIs, MySQL, PHP 7...
Playnance
Node.js, Solidity, MetaMask, React, Private NPM Modules, Web3.js...
Fabriik
Node.js, JavaScript, PostgreSQL, JSON/XML Schemas, REST APIs, Bookshelf.js...

Experience

  • SQL - 14 years
  • MySQL - 14 years
  • RESTful Development - 7 years
  • Node.js - 6 years
  • Linux - 6 years
  • Docker - 4 years
  • NestJS - 3 years
  • Amazon EC2 - 3 years

Availability

Part-time

Preferred Environment

Visual Studio Code (VS Code), GitHub, Git, GitLab CI/CD, Ubuntu, Linux, MacOS

The most amazing...

...product I've architected and developed was a platform that integrated different blockchains in a simple RESTful API—without any previous crypto experience.

Work Experience

Development Team Leader

2022 - 2023
Union Digital Inc
  • Led a team of five developers maintaining and improving the existing system while developing a new version.
  • Containerized existing PHP services and created a new deployment pipeline using AWS ECS, ECR, and CloudWatch.
  • Implemented a CI/CD pipeline with code standard checks and tests.
  • Architected a new version in Node.js and React to unify the sign-in for all the per-client deployed instances.
  • Conducted presentations to the rest of the company on the technical roadmap and its fulfillment.
Technologies: Node.js, NestJS, React, React Native, Chakra UI, REST APIs, MySQL, PHP 7, Docker, Amazon Elastic Container Service (ECS), Amazon Elastic Container Registry (ECR), Amazon RDS, Next.js, Amazon S3 (AWS S3), Jest, Expo Toolchain, RabbitMQ, CI/CD Pipelines, TypeScript, Front-end, Single Sign-on (SSO), Web App Development, DevOps, Prisma, Code Review, Team Leadership, Database Architecture, Authentication, OAuth, API Design, API/Services Architecture, ESLint, Expo, JSX, Mobile Development, Cross-platform, Cross-platform App Development, Testing, Version Control, GitHub, Sentry, Sass, Cloud Architecture, Test-driven Development (TDD), TypeORM, Database Structure, RESTFul APIs

Freelance Developer

2021 - 2021
Playnance
  • Designed a crypto gambling game involving microservices and smart contracts.
  • Developed the game's smart contract in Solidity, in charge of accepting bets and distributing winnings.
  • Conducted the complete CI/CD setup in GitLab and the testing environment in AWS using Terraform.
  • Integrated MetaMask wallet in the front end to perform operations with the game contract.
Technologies: Node.js, Solidity, MetaMask, React, Private NPM Modules, Web3.js, Full-stack Development, Software Architecture, Web, API Integration, Amazon S3 (AWS S3), Jest, CI/CD Pipelines, Code Review, WebSockets, API/Services Architecture, ESLint, Testing, Version Control, Crypto, Test-driven Development (TDD), Web3, Database Structure

Senior Full-stack Developer

2020 - 2021
Fabriik
  • Created a protocol to store and transfer tokens using the Bitcoin SV blockchain.
  • Developed a prototype application to manage tokens from scratch.
  • Improved the performance of a 2+ years application that handled thousands of transactions daily.
  • Added new features to a live application with thousands of users working from design to delivery.
Technologies: Node.js, JavaScript, PostgreSQL, JSON/XML Schemas, REST APIs, Bookshelf.js, React, Next.js, Figma, Kubernetes, GitHub, Kibana, Full-stack, Object-relational Mapping (ORM), Object-oriented Programming (OOP), SQL, Docker, Microservices, Databases, Git, NoSQL, NPM, CSS, Linux, Python, Bitcoin, RESTful Development, Unit Testing, Docker Compose, NGINX, Bash Script, HTML, Amazon Web Services (AWS), Architecture, JSON REST APIs, APIs, Redux, Containers, Leadership, Blockchain, Back-end, Web Applications, Web Application Architecture, Technical Leadership, Cryptocurrency, Web Development, HTML5, Full-stack Development, Web, Content Management Systems (CMS), Responsive Web Apps, Amazon S3 (AWS S3), Jest, RabbitMQ, CI/CD Pipelines, Front-end, Web App Development, DevOps, Code Review, Database Architecture, Authentication, OAuth, API Design, API/Services Architecture, ESLint, Microservices Architecture, JSX, Storybook, Testing, Version Control, Crypto, Sentry, WebApp, Cloud Architecture, Test-driven Development (TDD), Web3, Database Structure, RESTFul APIs

Team Leader - Blockchain Integration

2017 - 2019
DX Exchange
  • Designed a system to unify the interaction with blockchain technologies, providing a single RESTful API to retrieve and send transactions.
  • Led a team of five developers, QA, and DevOps, managing tasks and conducting code reviews using GitLab CI.
  • Conducted presentations about development advances and general technical concepts to non-technical personnel both inside and outside the company.
  • Developed specific complex components of the system providing patterns for other developers to follow.
  • Integrated more than ten different blockchain protocols.
  • Presented the product and blockchain technology to Cyprus's financial regulatory department.
Technologies: Amazon EC2, Amazon Simple Queue Service (SQS), Bitcoin, Ethereum, Solidity, React, MongoDB, TypeScript, Node.js, Docker, Microservices, Databases, Git, NoSQL, NPM, Linux, GitLab, RESTful Development, REST APIs, Object-oriented Programming (OOP), Unit Testing, Docker Compose, Laravel 5, Dependency Injection, Bash Script, Docker Swarm, Terraform, InfluxDB, Amazon Web Services (AWS), Full-stack, Architecture, JSON REST APIs, APIs, Containers, Object-relational Mapping (ORM), Integration, Leadership, Blockchain, Back-end, Web Applications, Web Application Architecture, Technical Leadership, Cryptocurrency, Web Development, Solution Architecture, Smart Contracts, HTML5, Full-stack Development, Software Architecture, Web, API Integration, Amazon S3 (AWS S3), Jest, CI/CD Pipelines, DevOps, Code Review, Team Leadership, Database Architecture, API Design, API/Services Architecture, ESLint, Microservices Architecture, Testing, Version Control, Crypto, Cloud Architecture, Test-driven Development (TDD), Web3, Database Structure, RESTFul APIs

Senior Full-stack Developer

2015 - 2016
SpotPaymentech
  • Designed the relational database for a credit card payments processor with multiple gateways and complex routing rules.
  • Developed gateway integrations with different APIs.
  • Implemented CI/CD solutions using GitLab CI, Docker, and Bash, adding code standard verification and running unit and integration tests.
  • Mentored developers on best practices, unit testing, code standards, and new technologies.
Technologies: Amazon EC2, MySQL, JavaScript, Angular, PHP, SQL, PHP 5, Docker, Microservices, Databases, Git, SQL Stored Procedures, NPM, PHP 7, Linux, GitLab, RESTful Development, REST APIs, Object-oriented Programming (OOP), Unit Testing, Docker Compose, Laravel 5, Unit of Work Pattern, Dependency Injection, Bash Script, Amazon Web Services (AWS), Full-stack, Architecture, JSON REST APIs, APIs, Containers, Object-relational Mapping (ORM), Integration, Leadership, LAMP, Laravel, Back-end, Web Applications, Web Application Architecture, Technical Leadership, Web Development, Solution Architecture, HTML5, Full-stack Development, Software Architecture, Web, API Integration, Amazon S3 (AWS S3), Jest, RabbitMQ, CI/CD Pipelines, Code Review, Database Architecture, API Design, API/Services Architecture, Online Payments, Testing, Version Control, Payment Gateways, Sass, Database Structure

Independent Developer

2006 - 2013
Freelance
  • Designed and developed systems independently for retailers, car rental companies, and the food industry.
  • Developed and designed a platform for online ticket selling, including a mobile app for validating tickets on-site.
  • Created and designed an online multiplayer poker game with a video chat.
  • Built and designed a video chat platform that was white label and sold to multiple clients.
  • Designed and developed an email marketing platform that managed millions of subscribers and sent thousands of emails per day.
  • Gathered requirements, conducting interviews with different stakeholders.
Technologies: SMTP, PhoneGap, PostgreSQL, MySQL, Flex, Flash, Cordova, JavaScript, PHP, SQL, PHP 5, Databases, Git, PHP 7, CSS, Linux, Python, RESTful Development, REST APIs, Object-oriented Programming (OOP), Cloudflare, HTML, Full-stack, Architecture, APIs, Object-relational Mapping (ORM), Integration, LAMP, Back-end, Web Applications, Web Application Architecture, Technical Leadership, Web Development, Solution Architecture, HTML5, Full-stack Development, Software Architecture, Web, Mobile, Front-end, Single Sign-on (SSO), Web App Development, Database Architecture, Google Maps, Version Control, Payment Gateways, Database Structure, Chart.js

Co-founder and Developer

2007 - 2012
MilMails Email Marketing Platform
  • Designed and developed a platform for email marketing for businesses.
  • Delivered more than one hundred thousand emails daily.
  • Managed a database with more than three million subscribers.
  • Implemented a Yahoo feedback loop and Microsoft junk mail program with smart network data services.
  • Implemented PayPal express checkout and Mercado Pago API for handling payments.
Technologies: CSS, HTML, jQuery, Linux, SMTP, PHP, SQL, PHP 5, MySQL, Databases, Git, RESTful Development, REST APIs, Object-oriented Programming (OOP), Full-stack, Architecture, APIs, Object-relational Mapping (ORM), LAMP, Back-end, Web Applications, Web Application Architecture, Technical Leadership, Web Development, Solution Architecture, HTML5, Full-stack Development, Software Architecture, Web, Front-end, IMAP, Database Architecture, Online Payments, Version Control, Payment Gateways, Sass, Email, Database Structure, Chart.js

Junior .NET Developer

2005 - 2005
Digbang
  • Developed forms to manage information for an educational institution.
  • Learned .NET and C# while working, having no previous experience in those languages.
  • Converted user stories into specific technical tasks.
Technologies: Microsoft SQL Server, C#, .NET, Web Development, Web, Version Control

Experience

Corporate Social Network

https://about.incircl.app
A serverless, Node.js/React platform that provides organizations with a private productivity-focused social network. I was in charge of the architecting and main implementation, both in back-end and front-end, as well as DevOps tasks.

Platform for Building Fitness Mobile Apps

Built using a serverless back end (AWS Lambda, Node.js, DynamoDB, S3), a React application for the front end, a static website generator (Jekyll) for the website, and React Native using Expo framework for the mobile application.

In addition to the development of the platform (back end, front end, and mobile app), I set up a CI/CD pipeline in GitLab and developed unit tests and end-to-end testing using the Cypress framework.

Website for Reviewing Workplaces

https://openqube.io/
A Node.js/React website, built as a single-page app, where employees can review their workplaces. I had to redesign and develop the current version, migrating data from a WordPress website and adding new features. Used MongoDB and InfluxDB for statistics. Configured the full CI/CD pipeline.

Graylog GitLab Alerts

https://github.com/elijahb/graylog-gitlab-alert
Developed a plugin in Java for Graylog to allow opening issues in GitLab whenever an alert is fired. I created this plugin as an effort to streamline bug fixing in our team, automating the process of opening issues for bugs with all related log information, enabling developers to focus on quick fixes.

Hybrid App for an Educational Institution's Catalog

Developed a prototype app for a startup using React with a Node.js back end where the same code was published as web and mobile apps using Apache Cordova/PhoneGap. The features included a chat that allowed people to ask questions about the different institutions.

Mobile Chat App for a TV Show

A TV show required a mobile chat app where actors could be filmed while chatting. I developed a React mobile app using Firebase to provide easy near-real-time streaming that allowed producers to interact with the mobile app enabling them to film actors having conversations with their phones.

BraidPay - a Web App to Receive Payments in Stable Coins

https://braidpay.com
A web app using React/Node.js to receive payments in stablecoins and create payment links and invoices. I was the only engineer to build the MVP from scratch. I implemented the Figma design in the Front End, built the back-end RESTful API, and integrated it with Plaid for KYC, PortalHQ for the self-custodial wallet, and Dynamic for authentication. I also had to set up the infrastructure using GitHub/AWS.

Education

2009 - 2013

Bachelor of Arts Degree (with Honors) in Information Systems

Buenos Aires National University (UBA) - Buenos Aires, Argentina

2000 - 2004

Technical School Degree in Information Technology

ORT Technical School - Buenos Aires, Argentina

Skills

Libraries/APIs

Node.js, React, REST APIs, React Redux, jQuery, AWS Amplify, Bookshelf.js, Web3.js, Google Maps, Chart.js, Context API, React Query

Tools

JSX, Redux Thunk, GitLab CI/CD, Docker Compose, GitHub, Git, NGINX, NPM, Amazon Elastic Container Service (ECS), RabbitMQ, Sentry, Amazon Simple Queue Service (SQS), Flash, GitLab, Docker Swarm, Terraform, Expo.io, AWS CloudFormation, Amazon CloudFront CDN, Figma, Kibana, Graylog, MetaMask, Amazon Elastic Container Registry (ECR), Expo Toolchain, AWS SDK, Prisma, Expo, AWS Key Management Service (KMS), Plaid

Languages

TypeScript, PHP, PHP 5, JavaScript, SQL, HTML, CSS, PHP 7, HTML5, Sass, Solidity, C#, SCSS, Python, Bash Script, C, Java

Frameworks

WebApp, Laravel 5, Express.js, Redux, Next.js, NestJS, Jest, Angular, Flex, PhoneGap, .NET, React Native, Serverless Framework, Bootstrap, Cypress, Laravel, Tailwind CSS

Paradigms

RESTful Development, Object-oriented Programming (OOP), Microservices, Unit Testing, Serverless Architecture, Web Application Architecture, DevOps, API/Services Architecture, Microservices Architecture, Testing, Test-driven Development (TDD), Dependency Injection, Object-relational Mapping (ORM), Mobile Development, Cross-platform

Platforms

Docker, Web, Amazon Web Services (AWS), LAMP, Blockchain, Ubuntu, Visual Studio Code (VS Code), Ethereum, Amazon EC2, AWS Lambda, Linux, Firebase, Kubernetes, Mobile, MacOS, PlanetScale

Storage

MySQL, Database Architecture, Database Structure, PostgreSQL, Databases, NoSQL, SQL Stored Procedures, Amazon DynamoDB, Microsoft SQL Server, MongoDB, Amazon S3 (AWS S3), InfluxDB, JSON/XML Schemas

Industry Expertise

Social Media

Other

Full-stack, Architecture, JSON REST APIs, APIs, Back-end, Technical Leadership, Web Development, Full-stack Development, API Integration, Web App Development, Minimum Viable Product (MVP), API Design, RESTFul APIs, Bitcoin, SMTP, Containers, Integration, Leadership, Web Applications, Cryptocurrency, Solution Architecture, Smart Contracts, Software Architecture, Content Management Systems (CMS), Responsive Web Apps, CI/CD Pipelines, Front-end, Single Sign-on (SSO), Code Review, Team Leadership, Authentication, OAuth, ESLint, Online Payments, API Gateways, Version Control, Payment Gateways, Crypto, Cloud Architecture, Email, TypeORM, Web3, Cordova, Cloudflare, Unit of Work Pattern, PWA, Mobile Apps, Private NPM Modules, Chakra UI, Amazon RDS, Amazon API Gateway, Hybrid Apps, Localization, IMAP, WebSockets, Storybook, Cross-platform App Development

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