Johann Villalvir

Senior Software Engineer

LunarCrush•  June 2024 - December 2024•  Remote

- Improved legacy React code based on best practices - Served as a lead front-end developer for improvements and mentored junior developers - Worked with Ethereum, Polygon, and other EVM-compatible chains, including deploying and integrating smart contracts using Solidity, Web3.js, and ethers.js. - Led migration of a large-scale web application from React and Node.js to Next.js and GraphQL, achieving significant performance and maintainability improvements. - Provided training and best practices to the development team for working with Next.js and GraphQL. - Refactored and updated the existing React Native applications for iOS and Android platforms.

Full-Stack Developer for Open Source Crypto Analytics Site

Escape Velocity•  October 2023 - June 2024•  Remote

- Implemented pixel-perfect and responsive frontend pages using React and Material UI, implementing dynamic components like tables, dialogs, modals, etc. - Developed RESTful APIs with Node.js and Express to handle user authentication and support CRUD operations like task management, category filtering, etc. - Integrated TypeScript for type safety across the front-end and back-end, improving code maintainability and quality. - Implemented Redux for global state management, optimizing data flow and ensuring seamless synchronization of user actions across components. - Optimized state updates and reduced unnecessary re-renders by integrating Redux-Thunk for asynchronous actions.

Frontend Engineer

Sparkrock•  March 2023 - August 2023

- Developed web frontend pages using Angular 10, TypeScript, Bootstrap, and LESS/CSS. - Translated Figma designs into pixel-perfect, mobile-friendly interfaces and built reusable Angular components. - Managed data by updating Microsoft 365 tables and integrated backend APIs built with .NET Core. - Collaborated with clients to gather and analyze requirements while providing comprehensive technical support.

Senior Frontend Developer

Laurel Road•  February 2022 - January 2023

- Refactored a large codebase to align with the latest React best practices and successfully migrated a React project from Reflux to Redux. - Integrated REST APIs using Redux-Thunk middleware and Axios for efficient state management and API consumption. - Optimized the project by implementing pixel-perfect Figma designs and streamlining the codebase for maintainability. - Updated and enhanced a private npm package for UI components to improve reusability and design consistency. - Managed and mentored junior developers, providing training on development processes, coding standards, and best practices.

Frontend Developer

Intellimize•  November 2021 - February 2022

- Built an Editor App using React.js, Redux, Redux-Saga, TypeScript, Jest, D3.js, Lodash, and other modern libraries. - Translated pixel-perfect Figma designs into functional features, enhancing the app's usability and visual appeal. - Resolved linting issues and wrote comprehensive unit tests using Jest and Mocha/Chai to ensure code quality and reliability. - Updated key components such as tooltips, dropdown selects, collapsible cards, and modals

React FullStack Developer

OmniScience•  July 2021 - November 2021

- Developed a feature-rich admin dashboard using React, GraphQL, Apollo, and React-Material-UI. - Converted pixel-perfect, mobile-friendly Figma designs into fully functional user interfaces. - Integrated AWS services like DynamoDB, AppSync, Cognito, and S3 for seamless backend functionality. - Designed and implemented GraphQL mutations, queries, and subscriptions with AppSync resolvers, integrating them effectively into the admin dashboard.

Senior Frontend Developer

CivImpact Labs•  March 2021 - June 2021

- Developed a single-page application using React, Redux, TypeScript, HTML5, CSS3, SCSS, and the OpenTok API. - Delivered a pixel-perfect, mobile-friendly UI for an enhanced user experience. - Implemented video and audio conferencing features using the OpenTok API and WebSocket API for real-time communication. - Integrated REST APIs efficiently with Axios and Redux-Thunk for seamless state management and data fetching.

Senior Frontend React Developer

Modzy, Inc.•  February 2021 - May 2021

- Developed an admin dashboard for Modzy using React.js, GraphQL, Apollo, ES6, HTML5, CSS3, SCSS, and D3.js. - Translated pixel-perfect InVision designs into functional, responsive user interfaces. - Designed and implemented complex data visualization charts using D3.js for clear and impactful insights. - Integrated GraphQL queries and mutations to enable efficient data interaction and management.

Senior React Developer

Etison, LLC•  October 2020 - January 2021

- Developed an Editor App for ClickFunnels using React.js, React Context, HTML5, CSS3, and Tailwind CSS. - Integrated REST APIs built with Ruby on Rails to enhance app functionality. - Implemented a Drag-and-Drop feature using the JavaScript Canvas API for improved user interaction. - Migrated ERB templates to React, improving performance and maintainability of the frontend.

Front-end Developer

ArcheTape, Inc•  February 2020 - August 2020

- Developed responsive web frontend pages and implemented mobile-friendly, pixel-perfect designs using React.js, Redux, HTML5, CSS3, and styled-components. - Delivered a marketing website utilizing React.js, HTML5, CSS3, and styled-components for seamless user experience. - Built a cross-platform mobile app for iOS and Android using React Native CLI, React, Redux, Redux-Thunk, Axios, and React Native packages. - Integrated third-party React and React Native packages such as Google Mapbox, DnD, and Stripe for enhanced functionality. - Implemented messaging features with the SendBird API and integrated Firebase Cloud Messaging (FCM) for push notifications.

Senior Front-end Engineer

LoungeBuddy, Inc•  January 2018 - January 2020•  Remote

- Developed responsive, mobile-friendly web frontend pages using React.js, Redux, HTML, CSS, and SASS/SCSS. - Successfully migrated an Angular app to React with minimal rewrite and disruption to functionality. - Integrated backend APIs with Redux-Saga and Axios, along with third-party systems like Greenhouse, Zendesk, and Marketo Forms. - Built an iOS app using React Native, React, and Redux-Thunk to ensure smooth cross-platform functionality. - Designed the mobile application to operate offline for extended periods, syncing data once online (with cellular reception). - Integrated unit testing with Jest and expanded test coverage of the existing application using Cypress.

Full Stack Developer

Pleroma Social•  June 2016 - November 2017

- Developed frontend pages using Vue.js, Vuex, Vuetify, HTML5, CSS3, and Bootstrap for a seamless user experience. - Redesigned and simplified an existing alerting application with over 100 form fields, significantly reducing customer support calls through an intuitive redesign. - Created a universal search feature for a customer-facing analytics application, enabling instant search across all data entities within a single interface. - Implemented various private APIs using Node.js and MongoDB to enhance backend functionality and support frontend operations.

Full Stack Developer

Freelancer•  February 2014 - May 2016

Developed web and mobile applications using a wide range of technologies, including React.js, Redux, Vue.js, Angular, and Node.js.