Romel Francisco Pérez Estrada, Developer in Medellín - Antioquia, Colombia
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Romel Francisco Pérez Estrada

Verified Expert  in Engineering

Front-end Developer

Medellín - Antioquia, Colombia
Toptal Member Since
August 10, 2022

Romel is a passionate front-end engineer with 10+ years of experience building web applications, design systems, frameworks, and UI tools for education, administration, marketing, entertainment, sales, web mapping, advertisement, trading, and construction. His specialties are TypeScript technologies focusing on scale, performance, and testability. Romel is enthusiastic about creating delightful user experiences. He is eager to contribute to projects to improve the world.


JavaScript, TypeScript, Design Systems, React, Emotion Library, Chrome DevTools...
JavaScript, TypeScript, React, Redux, Webpack, Cypress, Vue, Docker, Git, CSS...
JavaScript, React, Preact, Design Systems, GreenSock, Webpack, Firebase, Lerna...




Preferred Environment

MacOS, Visual Studio Code (VS Code), GitHub

The most amazing...

...project I've created is a framework to build web advertisement at scale with a focus on performance and extensibility, which triplicated delivery in two years.

Work Experience

Front-end Engineer

2022 - PRESENT
  • Specified, designed, and developed a web application for landowners, land agents, and project developers interested in restoration projects in the carbon market.
  • Supported the development of a single-page web application to manage small to medium-sized construction companies' administrative tasks.
  • Defined and developed a design system UI component library for a single-page web application to manage construction tasks, inventories, documents, and users.
  • Designed and developed a trading dashboard web application to visualize and analyze trading movements for an internal trading algorithm.
Technologies: JavaScript, TypeScript, Design Systems, React, Emotion Library, Chrome DevTools, Tailwind CSS, Docker, Git, Next.js, Netlify, CSS, HTML, Test-driven Development (TDD), Figma, Storybook, Express.js, REST APIs, Material Design, NPM, BEM, Functional Programming, Lucidchart, Flowcharts, Svelte, SvelteKit, Hasura, GraphQL, Front-end, Back-end, UI Components

Front-end Developer

2021 - 2021
  • Maintained functionalities in a gaming communication web app and a contentful website.
  • Created heavily animated, highly interactive, customizable, accessible, contentful, futuristic marketing pages for a gaming community.
  • Supported the architectural decisions for existing and new features in gaming community web apps.
Technologies: JavaScript, TypeScript, React, Redux, Webpack, Cypress, Vue, Docker, Git, CSS, HTML, Test-driven Development (TDD), Storybook, REST APIs, Sass, Lucidchart, Front-end

Web Engineer

2018 - 2020
  • Designed and developed an extensive framework to create a digital display web advertising system at scale with a focus on high performance and extensibility, which triplicated the production of ad units with faster and fewer processes in two years.
  • Migrated and upgraded a large and old external digital display web advertising system to a simpler, easier, and faster system to integrate with an existing one. The process required to design and develop two web applications for internal testing.
  • Mentored members of the team about internal tools, technologies, and engineering processes.
  • Reviewed development processes on multiple projects using shared internal tools and engineering practices.
Technologies: JavaScript, React, Preact, Design Systems, GreenSock, Webpack, Firebase, Lerna, Node.js, Sass, Atomic Design, Git, HTML, CSS, Test-driven Development (TDD), BEM, NPM, Functional Programming, Lucidchart, Flowcharts, Front-end, UI Components

Front-end Engineer

2017 - 2018
  • Developed and documented scalable, extensible, dynamic, and interactive UI 2D map library to use across different real-time web apps.
  • Created and maintained new features for a real-time web app for managing and monitoring electronic sensors and devices for industrial warehouses and storage buildings.
  • Supported the analysis and definition of technical specifications for internal tools shared across multiple projects.
Technologies: JavaScript, TypeScript, React, Design Systems, Leaflet, Angular, Git, Netlify, HTML, CSS, Test-driven Development (TDD), Flowcharts, Front-end, UI Components

Web Engineer

2017 - 2017
  • Designed and developed educative, multiplayer, real-time, high-performance, well-tested, and responsive web application video game for a university economy program.
  • Developed accessible and high-performance public forum manager progressive web application for unreliable internet connections.
  • Reviewed and created technical proposals for new software development projects for the company.
Technologies: JavaScript, React, Sass, Redux, Materialize, Material UI, Git, Node.js, Webpack, Socket.IO, MongoDB, DigitalOcean, HTML, CSS, Test-driven Development (TDD), Front-end, Back-end

Front-end Engineer

2015 - 2017
Vulcan Studios
  • Developed and maintained pixel-perfect responsive web SPAs, PWAs, contentful websites, design systems, and UI component libraries, with awesome user experiences in a high-paced environment.
  • Designed and developed a customizable UI component library to search and buy liquor online, which was implemented by multiple brands' websites.
  • Created an interactive educational platform for bartenders. It was composed of two web applications, the content manager and the customer interface.
  • Developed a pixel-perfect design system UI library for a small fruits and vegetables online marketplace.
  • Made a web application to manage governmental events for agricultural guilds.
  • Developed part of the UI components for a web platform that provides transfer money services for companies to sell products.
  • Built a progressive web application with offline support for the company providing hiking and trekking services to track events and record multimedia on travels.
Technologies: JavaScript, Backbone.js, React, jQuery, ZURB Foundation, Materialize, Git, Node.js, Sails.js, Webpack, RequireJS, Browserify, BEM, Atomic Design, Design Systems, MongoDB, MySQL, Mongoose, DigitalOcean, CSS, HTML, Test-driven Development (TDD), Express.js, NGINX, Redux, Sass, Front-end, UI Components, Full-stack

Junior Software Engineer

2012 - 2015
Grupo Calumet
  • Developed software tools to facilitate the development of university websites.
  • Designed and developed UI component library to use in university websites.
  • Mentored new students on web technologies, primarily JavaScript and related tools.
  • Created extensive technical documentation about the software tools used across multiple projects.
  • Developed desktop application to record, process, and store data from climatological sensors, a few web services to interpret the weather data, and web applications components to display weather information on multiple websites.
Technologies: JavaScript, jQuery, Git, Subversion (SVN), Java, Apache Tomcat, Apache, Jakarta Server Pages (JSP), Node.js, Grunt, Bootstrap, Backbone.js, CSS, HTML, Front-end, Back-end, UI Components, Full-stack

Junior Software Engineer

2014 - 2014
GRI Gestión Integral
  • Designed and developed the company website with general and service information.
  • Designed and developed an internal database management tool for clients' contract data.
  • Gained knowledge about general software engineering development.
Technologies: PHP, Apache, MySQL, JavaScript, Git, jQuery, HTML, CSS, Front-end, Back-end, Full-stack

Developed a real-time JavaScript and TypeScript UI playground. Noxtron is a configurable web tool to explore, preview, and test JavaScript and TypeScript components in the browser as isolated sandboxes in real time. It comprises two applications, a playground app with the interface to explore and control predefined sandboxes and a sandbox app to execute the sandboxes' source code.

Arwes is a web framework for building user interfaces based on futuristic science fiction designs, animations, and sound effects. The concepts behind are opinionated with influences from cyberprep and synthwave and productions like Star Citizen, Halo, and Tron: Legacy. It tries to inspire advanced space and alien technology.

Real World React Website
The website for Real World React. Real World React is a professional services and consulting firm specializing in modern front-end tools and serverless architecture. It also provides training, remote placement, and engineering retreat services.

Soul Extract Website
Soul Extract is an alternative rock music producer injected with electronic and cinematic elements. Proud member of the FiXT family. The website project required science fiction visuals, animations, and sound effects featuring the Soul Extract brand identity.

CSS in JavaScript with JSS and React Article
Styling scalable web applications is hard. Though CSS and its many tools provide various solutions to implement designs, there are still problems when projects get more complex or when many people start to share the same codebase. This is an article about how to use CSSinJS in web applications at scale.


React, Node.js, Emotion Library, Anime.js, REST APIs, Backbone.js, jQuery, Vue, Preact, Leaflet, RequireJS, Socket.IO


NPM, Git, Webpack, Figma, Lerna, Lucidchart, JSS, GitHub, NGINX, GreenSock, Browserify, Subversion (SVN), Apache Tomcat, Apache, Grunt, Mongoose


Material UI, Next.js, Express.js, Redux, Materialize, Tailwind CSS, Svelte, Chrome, Cypress, Angular, ZURB Foundation, Sails.js, Jakarta Server Pages (JSP), Bootstrap


JavaScript, TypeScript, Sass, CSS, HTML, Java, PHP, GraphQL


Test-driven Development (TDD), BEM, Functional Programming


MongoDB, MySQL, Hasura


MacOS, Visual Studio Code (VS Code), Docker, Firebase, DigitalOcean, Netlify


Design Systems, Chrome DevTools, Front-end, UI Components, Effector, Material Design, Atomic Design, Storybook, UI Motion, SvelteKit, Flowcharts, Gatsby, Back-end, Full-stack

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