Hi, there

I’m Eugene Cozac

Senior Front End Engineer (React.js/Next.js/Node.js)

11 years of development experience, working on multiple complex web applications (SPA, SSR) using React.js and Next.js, with various combinations of tech stacks such as Headless CMS, SWR, SocketIO, TanStack, A11y, and Redux. For the past 4 years, I have predominantly led projects, created architectures, conducted demos, and served as a key developer. I have also assisted in conducting interviews and helped teams to eliminate technical debt. Used GraphQL (queries and mutations) in Next.js and React.js applications and participated in migrations from RESTful API to GraphQL and vice versa,

About my experience

Developed various Next.js web applications (including version 14) with Server Components, custom authorization, and NextAuth. Utilized headless CMS solutions such as Prismic, Sanity, Contentful, and implemented internationalization with the i18next framework. I have experience working with Next.js versions 11 through 15. Additionally, I optimized server-side rendering (SSR), validated caches, and optimized data. Utilized Babel.js for transpilation, along with ESLint and Prettier for code linting and formatting, respectively. Implemented Vite for fast and efficient build processes and Husky to manage Git hooks, ensuring clean, professional, and maintainable code;

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Tailwind CSS, Material UI
React.js/Redux
Next.js
JavaScript/TypeScript
my resume

My Education & Experience

Created various SPAs using React.js for both small and large companies, ranging from simple apps to projects with complex architecture and numerous custom npm packages, functionalities, and hooks. Over the past 5 years, I have utilized a diverse React.js tech stack, from Class Components, CRA, Yup, ContextAPI, React Router to TypeScript, hooks, Vite, Zod, Quill, shadcn/ui, Jotai, ReduxToolkit, and TanStack. Experienced in utilizing various UI libraries such as Tailwind, MaterialUI, Radix, Bootstrap, and shadcn/ui. Proficient in styling techniques including CSS Modules, SASS, and styled-components. For most of the apps, I used Jest or Vitest with React Testing Library for unit and integration testing. Additionally, I have experience with E2E testing using Cypress.

Experience

Experience

2023 - now

Senior React.js Developer

GAN

Built two high-value projects from scratch on Next.js 14 for Maryland Casino and Parx Casino, enhancing their online casino platforms.

·    Implemented NextAuth for secure authentication and utilized Headless CMS solutions like Strapi to manage content effectively. Employed i18next for internationalization, ensuring the platforms could cater to a global audience. Deployed the applications on Vercel for optimized performance and scalability.

·    Leveraged ContextAPI and Zod for state management and data validation, while maintaining UI consistency with Storybook and adhering to Atomic Design principles.

·    Integrated GraphQL with Headless CMS solutions like Strapi for efficient data querying and content delivery, ensuring seamless integration with Next.js. Used Visx for advanced data visualization, creating dynamic and interactive interfaces. Ensured code quality and reliability through rigorous testing with React Testing Library.

2023 - 2023

Lead React.js Developer

Intel471

Led the development of a groundbreaking cyber security intelligence platform, covering adversary, credential, malware, vulnerability, and marketplace intelligence domains.

·    Architected and developed a SPA for a cybersecurity intelligence platform from scratch, focusing on adversary, credential, malware, vulnerability, and marketplace intelligence domains. Designed the application's architecture using Redux Toolkit for state management, React Hook Form with Yup validation, and Recharts for dynamic data visualization.

·    Led the UI team in the development of a cybersecurity intelligence platform, taking a hands-on approach in guiding the project’s direction and ensuring high-quality deliverables. Played a key role in building the team from the ground up, including participating in the hiring process and mentoring new developers to ensure they quickly adapted to project requirements and company standards.

·    Optimized the platform's performance, scalability, and security, utilizing RESTful API, TanStack Query, React Query & Tailwind CSS. Enhanced the platform’s functionality with Storybook for component management, React Intl for internationalization, and Lazy Loading and Suspense for improved load times. Ensured robust testing with Jest and RTL, elevating the platform's effectiveness in supporting cybersecurity strategies.

2022 - 2023

Senior React.js Developer

Shell Energy

Created the front end of AI-based chat applications from scratch (LNG, Shell-e, and Aviation), with LNG alone valued at £23 million.

·    Created a Single Page Application (SPA) from scratch, utilizing React and Redux-Toolkit for state management, along with React Hook Form integrated with Yup for validation. Developed a consistent and accessible UI using Storybook and Tailwind CSS, while ensuring code quality and maintainability with Vite, ESLint, Prettier, and A11y best practices.

·    Following the successful completion of the LNG project, which established the foundation for AI-driven chat applications. I was key in designing the architecture, coding the front-end in React, and showcasing the project to 1,800 Shell employees, earning high praise from top management.

Following the successful LNG project, I led the development of Shell-e and Aviation, building on the LNG framework to enhance information retrieval and operational efficiency through AI-driven virtual SMEs.

2021 - 2022

Senior Senior Front End Developer

Citi Bank

Worked on Knockout.js application for business customers, focusing on data analysis and visualization.

·    Developed custom web components for a data analysis and visualization application using Knockout.js in combination with React.js. Implemented end-to-end testing with Cypress to ensure the reliability and performance of the application across different user scenarios.

·    Employed CSS Modules for modular and maintainable styling, ensuring a consistent and responsive user interface. Integrated React Chartjs 2 for creating dynamic and interactive data visualizations, enhancing the analytical capabilities of the app. Maintained high code quality by enforcing coding standards and formatting rules using ESLint and Prettier.

2020 - 2021

Lead Front End Developer

GAN

Created a framework and npm packages for Next.js tailored for top online casino gambling websites, including Borgata Casino, Bellagio Casino, WinStar World Casino, Wynn Las Vegas Casino.

·    Developed a Next.js boilerplate for multiple gambling websites, utilizing Incremental Static Regeneration (ISR). Built custom npm packages and integrated GraphQL, MaterialUI, and TanStack Query for efficient data management and UI consistency. Deployed via Vercel and maintained code quality with ESLint, Prettier, and Storybook.

·    Custom hooks and API calls were used to fetch structured content from the CMS, while GraphQL queries facilitated efficient data retrieval. Leveraged Next.js with headless CMS solutions like Prismic and Contentful to create dynamic, content-driven websites, integrating these platforms deeply into the workflow to enable seamless content management for non-technical users.

2019 - 2020

Senior Full Stack Developer

KP Acoustics

Created a full-stack CRM system from scratch with specialized functionality for construction acoustics, enhancing project management and client interactions.

·    The full-stack dashboard was built using the PERN stack (PostgreSQL, Express, React, Node.js) and featured robust authorization, user roles, and CRUD operations. Additionally, the system included advanced functionalities such as data sorting, pagination, invoicing, an address book, a ticket system, and an integrated calendar for managing events.

·    Designed and developed a relational database using PostgreSQL with complex relationships to support the system’s functionalities. Built the server-side logic with ExpressJS and NodeJS, creating RESTful API endpoints for efficient data handling. Utilized TypeORM and Sequelize for object-relational mapping and database management. Implemented robust authentication and security features using Passport.js, bcrypt for password hashing, and Multer for file uploads.

2018 - 2019

Senior Senior Front End Developer

LMAX Exchange

Developed a complex trading crypto app serving clients in over 100 countries, handling up to 400 million orders daily.

·    Worked on a high-performance trading platform, optimizing it for handling high-traffic loads. Utilized ContextAPI for state management and Radix for UI primitives. Implemented accessibility best practices (A11y) and integrated React Intl to support internationalization, ensuring the platform could cater to a global user base.

·    Utilized D3.js for data visualization, creating interactive graphs to display trading activity. Enhanced the user interface with Materialize for a  responsive design, and implemented form handling with Formik and Yup. Integrated Firebase for real-time data management and synchronization.

·    Conducted comprehensive testing using Jest and React Testing Library (RTL), implementing unit tests, integration tests, and snapshot tests to ensure application reliability and performance.

2018 - 2018

Senior Front End Developer

ReceiptBank-Dext

Worked on accounting automation software, providing solutions that simplify tasks for accountants, bookkeepers, and businesses,  ensuring accurate data and efficiency.

·    Developed and integrated custom accounting automation software with major industry platforms like Xero and QuickBooks, significantly enhancing the tool’s capabilities and ensuring seamless data flow.

·    Created robust dashboards using React Class Components, providing accountants and bookkeepers with essential insights. Leveraged technologies such as PropTypes for type-checking, Formik for building dynamic custom forms, and Recharts for interactive financial graphs.

·    Utilized CSS Modules for modular styling, Firebase for real-time database management, and Redux with Redux Thunk for state management. Implemented best practices with CRA, Atomic Design, and A11y to ensure a scalable and accessible front-end architecture.

2016 - 2017

Senior Software Engineer

Samsung Research America

Worked on the Samsung Pay app as the lead of Promotions Team.

·    Led UI/UX Development: Spearheaded the design and development of hybrid mobile applications for the Samsung Pay app, utilizing AngularJS and MaterialUI. Ensured robust testing and quality assurance through tools like Protractor, Karma, and Jasmine.

Participated in development of microservices using Spring MVC, Spring Boot, Spring AOP, and JPA. Implemented RESTful APIs and managed database interactions with MySQL.

·    Enhanced the AngularJS front end with custom functionality, leveraging tools like Moment.js, Gulp, Babel, and Browserify/Uglify to optimize performance and code efficiency.

·    Tackled the complexities of AngularJS (Angular 1.x) by optimizing the digest cycle for performance, implementing custom directives, and managing hierarchical scope inheritance. Developed sophisticated UI components for the Samsung Pay app, leveraging the power of AngularJS’s two-way data binding and dependency injection, while ensuring high performance and scalability across the application.

2015 - 2016

Front End Developer

Kaiser Permanente

Implemented complex JavaScript functionalities for a healthcare provider's Sharepoint application.

·    Utilized ES6, Lodash, and Underscore for complex DOM manipulations within SharePoint, significantly enhancing user interface interactions and the overall functionality of the healthcare provider's internal systems. Developed dynamic JavaScript templates to streamline the creation  and management of UI components.

·    Integrated and manipulated data from complex RESTful APIs, ensuring seamless data flow and enhancing the performance of the application by efficiently handling API responses.

·    Applied OOP to design modular, reusable components for efficiently managing complex medical data in a healthcare application, enhancing system scalability and maintainability.

2014 - 2015

Web Developer

ThemesTune

Developed multiple e-commerce WordPress templates for ThemeForest.

·    Created high-quality WordPress templates for ThemeForest, with a strong focus on e-commerce functionality. Leveraged frameworks like Bootstrap and Foundation to ensure responsive design, and integrated WooCommerce for seamless online shopping experiences.

·    Developed numerous custom PHP plugins and widgets, significantly enhancing the customization capabilities of the WordPress themes. Designed a flexible custom theme framework, allowing users to easily modify options and tailor the template to their specific needs.

·    Extended the capabilities of MySQL databases with additional tables and implementing additional fields, enabling greater flexibility and functionality within the themes.

2013 - 2014

Web Developer

Best4u Media B.V.

Built a Greenfield project for a fintech platform and a social networking application for a healthcare initiative, both for companies in the Netherlands.

·    Built the user interface from the ground up using Bootstrap and SASS, combined with JavaScript (ES5). The front end was fully AJAX-driven, heavily utilizing jQuery along with custom plugins to enhance interactivity and responsiveness across the platform.

·    Developed custom widgets and plugins in PHP for Drupal and WordPress also crafted tailored queries in MySQL to manage complex data operations. Ensured seamless integration between front-end components and backend systems, optimizing data retrieval and performance across the application.

Education

Education

2005 - 2009

BS in Computer Engineering

Technical University of Moldova

Building and assembling computing machines

2015 - 2017

MS in Computer Science

California Takshila University

Solving with algorithms and data structures

my skills

My Skills Areas

Solid experience building full-stack web applications from scratch using Node.js and Express.js, along with various tools such as Nodemon, Winston, Axios, JWT, and Passport.js. Proficient in working with both relational and non-relational databases, including PostgreSQL and MongoDB, and using ORMs like Mongoose, Prisma, Sequelize, and TypeORM;

JavaScript/TypeScript
React.js/Redux
Next.js
Node.js/Express.js
experience

Past Experience

With over 7 years of deep expertise in JavaScript, including frameworks and libraries like React, Next.js, and Node.js, and more than 11 years of comprehensive experience in web development, I have consistently delivered innovative and high-performance web applications.

SSR

For server-side rendering (SSR), I leveraged Next.js, including Next 14, to enhance the internal framework with NextAuth for authentication, Headless CMS integrations like Strapi and Contentful, and internationalization using i18next, all optimized for Vercel deployment.

SPA

I've built over two dozen SPAs with ReactJS, utilizing technologies like TanStack Query, React Router, SWR, and ContextAPI. I’ve also integrated tools like Storybook, Formik, and Vite, while implementing advanced features such as Lazy Loading, Suspense, Concurrent Rendering, and A11y best practices.

Node.js

I've worked extensively with Node.js, using Express.js, Prisma, and Sequelize for backend development, implementing JWT for authentication, and leveraging Mongoose and Apollo Server for database and API integration.

contact

Contact with me

You can easily drop me an e-mail or just send a phone message.

Get in touch
Location

Greenwich, SE9 6FS

London, UK

Phone
+44 7517453892

 

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