UNfavor
Developed an app called UNfavor that connects users who want to exchange favors using a recommendation system. Built on React.js, Redux, mongoDB, and Express.js.
Full Stack Engineer
Open to full-time
Bio
Juan J is a Full Stack Engineer with several years of experience in building web applications, specializing in React and TypeScript. He utilizes React.js, Next.js, TypeScript, Redux, and Express.js to develop web applications, including REST APIs and relational databases like MariaDB and PostgreSQL. His development practices include unit and integration testing with Vitest and Jest, as well as deploying applications on AWS using Docker-compose, EC2, and S3. At Rondhuit in Tokyo, Juan developed client-specific features using React and TypeScript and managed testing infrastructure migrations. During his tenure at the National University of Colombia, he maintained a reporting system that processed data for over 7,100 students annually and led modernization efforts for legacy applications. Juan is pursuing a Computer Science and Engineering degree at the National University of Colombia and holds an AWS Academy Cloud Foundations certification. He is well-suited for React and TypeScript frontend projects, particularly those involving testing infrastructure and legacy system modernization.
Expertise
ReactTypeScriptJavaScriptNext.jsAWSSQLPythonGitHTMLCSSFlutterMongoDB
Video Intro
Assessments
General Project Assessment
(80/100)- Great on Find the Length of the Longest Substring Without Repeating CharactersEasy
- Great on Optimize Product Page Load TimeMedium
- Great on Sharing Authenticated User Data Across the AppMedium
Projects
GWhats
Developed an app to remaster the Gmail UI to work like Whatsapp. Built on React.js and uses Google APIs.
Portfolio
Development of a portfolio using only pure javascript, css, and html to understand the problems of not using a modern frontend framework.
EVoting
Developed a mobile electronic voting application for the university to learn more about Flutter, Dart, and mobile development.
Experience
Frontend Developer
Rondhuit· Enterprise & SaaSAug 2024 — Feb 2026- Developed custom features based on client requests using React.js and Typescript
- Wrote unit and integration tests using Vitest, React Testing Library + Jest, and Vitest + browser mode
- Managed project dependency upgrades and performance optimization
React.jsTypescriptVitestReact Testing LibraryJestCreate React AppViteReact RouterReact HooksCSS3Fullstack Developer
National University of Colombia· EdTechFeb 2021 — Aug 2024- Designed and implemented web applications using React.js/Next.js, Typescript, Redux, Express.js, Django API Rest, MariaDB, and Postgresql
- Managed maintenance of a reporting system for over 7,100 students
- Maintained architecture on AWS with Docker-compose, EC2, S3, Nginx
React.jsNext.jsTypescriptReduxExpress.jsDjango API RestMariaDBPostgresqlAWSDocker-composeEC2S3NginxPythonCSS3Frontend Developer
Code LabsAug 2019 — Aug 2020- Translated UI designer's designs into web layouts using various technologies
- Performed quality assurance checks on company websites
- Collaborated with UI designers to optimize web layouts
JavascriptJqueryHTMLCSSSASSgulpbabel
Education
Computer Science - Exchange program
Hiroshima UniversityHiroshima, Japan2025 — 2026Computer Science - Exchange program - GPA (A)
Waseda UniversityTokyo, Japan2024 — 2025Computer Science and Engineering
National University of ColombiaBogotá, Colombia2020 — 2024Systems and Computing Engineering - Exchange Program - GPA (4.5/5.0)
Los Andes UniversityBogotá, Colombia2023 — 2023Software Programming Technician - GPA (4.5/5.0)
SENABogotá, Colombia2019 — 2020
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