Radu is available for hire
Hire RaduRadu Cojocaru
Verified Expert in Engineering
JavaScript Developer
Timișoara, Timiș County, Romania
Toptal member since January 3, 2018
Bio
Radu is a senior full-stack engineer with 22 years of experience, working mostly with React, TypeScript, Vite, and Node.js. His recent roles focus on front-end development, involving extensive tooling like mock servers, developer tools, and optimized CI processes. He recently contributed to building Sky's new identity portal from scratch. Radu uses AI coding agents daily and has developed his own agent pipeline, handling everything from rough tickets to reviewed pull requests.
Portfolio
Sky via a Consultancy
SolidJS, TypeScript, Vite, Sass, Vitest, Playwright, Node.js, Koa...
Vodafone UK via a Tech and Consultancy Company
Express.js, Node.js, Cypress, Storybook, Jest, React, Front-end, HTML, HTML5...
Kalepa
Amazon Web Services (AWS), APIs, Python 3, Redux, ECMAScript (ES6), JavaScript...
Experience
- JavaScript - 20 years
- Node.js - 10 years
- React - 8 years
- TypeScript - 7 years
- Jest - 6 years
- Redux - 5 years
- SolidJS - 3 years
- Vite - 3 years
Work Experience
Senior Front-end Engineer
2023 - 2026
Sky via a Consultancy
- Helped build Sky's new identity portal (id.sky.com) from greenfield to production as one of its two founding front-end engineers, using SolidJS, TypeScript, and Vite.
- Delivered multi-factor authentication end-to-end, including enrollment, the sign-in challenge, recovery codes, and account recovery.
- Hardened the login pages with a Content Security Policy at the CDN (Amazon CloudFront), bot-mitigation and device-risk integrations, and allow-listing of redirect URLs.
- Cut CI build times from 15–17 minutes to under 8 and set up "build once, deploy many" on AWS CodeBuild.
- Built a mock server that let the team work in parallel with the back-end teams, plus a Chrome extension that made switching between mock scenarios one click.
- Created a component inspector and a gallery of UI flows that product and QA used as a quick way to see user journeys.
- Migrated other Sky web apps to the new identity platform, so the legacy system could be largely switched off.
- Worked on device management and early migration to another identity platform.
Technologies: SolidJS, TypeScript, Vite, Sass, Vitest, Playwright, Node.js, Koa, Amazon CloudFront, AWS CodeBuild, Chrome Extensions, Multi-factor Authentication (MFA), Front-end, Single-page Applications (SPAs), Web Development, REST APIs, Authentication, Automated Testing, CI/CD Pipelines, Amazon Web Services (AWS), AI Tools, GitHub Actions, Test Automation, Migration, AI Agents
React Developer
2018 - 2023
Vodafone UK via a Tech and Consultancy Company
- Built the Vodafone Care phone insurance shop (eshop.care.vodafone.com/uk): a multi-section form customized per country, using code splitting.
- Developed the React front end for Vodafone's payments page.
- Made an npm package, a brand-aligned React components library, that was being used in five projects.
- Created a CLI similar to Create React App that was being used for scaffolding a new React project with specific Vodafone customizations.
- Added Jest unit tests for the React front end, achieving code coverage above 50%.
- Created a mocking library package as an npm package that was used to mock REST API requests in several projects.
- Added end-to-end tests using Cypress running in the CI environment.
- Created a preview web app and translation tool that was being used to preview different user journeys and to provide translations visually.
Technologies: Express.js, Node.js, Cypress, Storybook, Jest, React, Front-end, HTML, HTML5, UI Libraries, Redux Thunk, Functional Programming, Amazon S3 (AWS S3), TypeScript, Axios, APIs, Application State Management, ECMAScript (ES6), Web Development, REST APIs, Automated Testing, Test Automation
React Developer
2019 - 2020
Kalepa
- Worked on Kalepa, an AI underwriting platform that gives commercial insurance underwriters risk insights and automates the manual steps of their workflow.
- Developed the front end for the main application used daily by underwriters.
- Created a React components library according to the design language provided by the design team.
- Contributed to the Python back-end application by updating and adding new APIs.
Technologies: Amazon Web Services (AWS), APIs, Python 3, Redux, ECMAScript (ES6), JavaScript, Front-end, HTML, Data Visualization, Communication, Axios, Application State Management, Web Development, Python, REST APIs, Automated Testing, Back-end Development
Full-stack Developer
2018 - 2018
VoxGig
- Created the talk proposals management software to keep track of and review proposals for a conference.
- Created microservices using the Seneca framework, with Vue and React front ends.
- Reduced micro-app development time by creating a template with common components.
Technologies: JavaScript, Seneca.js, Node.js, Front-end, HTML, APIs, Vue, React, Web Development
React Developer
2016 - 2018
Vodafone UK via a Tech and Consultancy Company
- Worked as part of the front-end team to develop the React web app at offers.vodafone.com.
- Developed, on my own initiative, a Node.js and Express server that mocked a complex transaction API, letting the front end work without waiting on the back end and cutting development time in half.
- Developed the authentication solution and permissions system for a separate CMS application. Used Node.js for the back end and React for the front- end.
- Introduced tests, specifically unit testing, integration testing, and snapshot testing using Jest.
- Integrated the front-end build with the Java back-end build through a front-end-maven plugin.
- Maintained, refactored, and expanded Cucumber end-to-end tests.
- Added a live preview to the offer editor: it loaded the real application in an iframe and injected each offer's values as editors typed, so they saw instantly what customers would see.
Technologies: Java, Sass, Express.js, Node.js, Jest, Webpack, Redux, React, ECMAScript (ES6), Front-end, HTML, APIs, Web Development
Front-end Web Developer
2013 - 2016
Vodafone DE
- Led a small front-end team (up to four developers) building start.vodafone.com, a single-page web application providing Vodafone customers with info about Vodafone services.
- Developed a custom model–view–controller (MVC) framework for JavaScript.
- Customized the web app to integrate seamlessly with native iOS and Android apps.
- Developed JavaScript animations that coordinate with Ajax requests.
- Reduced page load times by optimizing asset sizing and bundling.
- Mentored the developers in India who took over the project, including about a month in Düsseldorf for the handover.
Technologies: Sass, Agile Software Development, CSS, JavaScript, Front-end, HTML, Web Development, Technical Leadership
Web Developer and Native Mobile App Developer
2011 - 2013
Betfair London
- Worked on a betting iOS (Objective-C) mobile app developed specifically for the Euro 2012 championship.
- Developed a mobile web app to handle registration, login, and account management for Betfair customers on the web and in different mobile apps.
- Integrated the web app for user registration inside a few native iOS mobile apps using WebView.
Technologies: Objective-C, JavaScript, Front-end
Web and Mobile App Developer
2011 - 2011
BullionVault
- Designed the first version of the BullionVault mobile app.
- Developed the iOS version of the app with Objective-C.
- Created the Android version of the mobile app with Java.
Technologies: Java, Objective-C
Mobile App Developer
2010 - 2010
LMAX Exchange London
- Developed the first version of the iOS native mobile app for the LMAX Exchange.
- Enabled LMAX customers to place trades on the LMAX real-time Forex exchange.
- Ensured smooth app performance as forex is a fast-moving market and displaying accurate prices and order book data was essential.
Technologies: Objective-C
Full-stack Developer
2006 - 2010
SurgeWorks.com, Inc.
- Worked on a web portal using Ruby on Rails for AT&T.
- Developed several iOS (Objective-C) apps, including Divine Office, a prayer app.
- Worked on a few plugins to customize WordPress for ExtremeMember.com.
Technologies: Objective-C, Ruby, PostgreSQL, PHP, WordPress, Full-stack Development, Full-stack, Relational Databases, Ruby on Rails (RoR), Back-end Development
Full-stack Developer
2004 - 2006
Freelance
- Worked on 30 small and medium projects, developing web and Windows applications.
- Built web scrapers for keyword research websites.
- Developed websites for an auto dealership and a food portal.
Technologies: MySQL, C#, WordPress, PHP
Experience
WebMend, a Side Project Built with AI Agents
https://webmend.appA side project I built in 2026 to explore working with AI coding agents: a Chrome extension (about 500 installs) for annotated bug reports, an embeddable feedback widget, and a website scanner for broken links, typos, and accessibility issues. I designed it and made the architecture, stack, and product decisions; AI agents did most of the implementation through a pipeline I built around Claude Code, turning rough tickets into reviewed pull requests. About 400 PRs were merged in six weeks. It runs on Cloudflare Workers and R2, with the API on Hetzner.
Sky's New Identity Portal
https://id.sky.comSky iD is the identity platform behind every Sky customer sign-in (sky.com, Sky Go, Sky Sports, Sky Store), handling hundreds of thousands to millions of sign-ins a day. As one of two founding frontend engineers, I helped take the new portal from greenfield to production. We picked SolidJS for its small bundles and React-like syntax, and shipped a fully static single-page app from AWS CloudFront, so the app loads instantly even during sign-in peaks around big football matches. One codebase is themed per Sky service. Along the way, I built the team's tooling: CI down from 15–17 minutes to under 8, a mock server, and a Chrome extension for one-click mock scenarios.
Vodafone Care
https://eshop.care.vodafone.com/uk/A React web app where Vodafone customers can buy insurance for their phones. The app consists primarily of a large form split into three sections:
• select device,
• select the level of coverage,
• fill in personal details.
The form needs to be customized based on the user's country, and we used code splitting (loadable components) to handle the different variants.
As part of this project, I also worked on a components library that follows the Vodafone style guide and is used in multiple projects for a consistent UI and faster development.
• select device,
• select the level of coverage,
• fill in personal details.
The form needs to be customized based on the user's country, and we used code splitting (loadable components) to handle the different variants.
As part of this project, I also worked on a components library that follows the Vodafone style guide and is used in multiple projects for a consistent UI and faster development.
Education
2003 - 2008
Engineer's Degree in Computer Engineering, Faculty of Automation and Computers
Politehnica University of Timișoara - Timișoara, Romania
Skills
Libraries/APIs
React, Node.js, SolidJS, REST APIs, React Redux, Seneca.js, Playwright, Vue
Tools
Redux Thunk, Claude, Git, Webpack, NPM, Vitest, Amazon CloudFront, AWS CodeBuild, Claude Code
Languages
JavaScript, TypeScript, Sass, Objective-C, Ruby, HTML, HTML5, ECMAScript (ES6), Java, CSS, Python 3, PHP, C#, Python
Frameworks
Redux, Jest, Express.js, Cypress, Next.js, Koa, Ruby on Rails (RoR)
Paradigms
Agile Software Development, Automated Testing, Test Automation, Functional Programming
Storage
MySQL, Relational Databases, PostgreSQL, Amazon S3 (AWS S3), SQLite
Platforms
MacOS, Amazon Web Services (AWS), Firebase, Web, WordPress
Other
Front-end, Vite, Web Development, Agentic AI Systems, APIs, UI Libraries, English, Axios, Application State Management, AI Agents, LLM Integration, Full-stack Development, Full-stack, AI Integration, Authentication, CI/CD Pipelines, AI-assisted Development, AI Tools, Agentic Coding, Back-end Development, Storybook, Styled-components, Data Visualization, Algorithms, Communication, Chrome Extensions, Multi-factor Authentication (MFA), Single-page Applications (SPAs), Cloudflare, Cloudflare R2, Hono, GitHub Actions, Cloudflare D1, Technical Leadership, Migration
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