PhyongNam Kim, Developer in Seoul, South Korea
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PhyongNam Kim

Verified Expert  in Engineering

Full-stack Developer

Seoul, South Korea
Toptal Member Since
September 19, 2019

Kim is an accomplished full-stack developer committed to building outstanding websites and mobile apps. With his expertise in JavaScript, he skillfully leverages cutting-edge technologies to create visually stunning, user-friendly, secure, and performant experiences. Kim's impressive track record encompasses developing large-scale applications from scratch, driving user growth, boosting revenue, and fueling expansion through exceptional work.


CSS, React, REST APIs, Bootstrap, MobX, TypeScript, Storybook, Figma, Jest...
JavaScript, TypeScript, Vue, Nuxt.js, Vuex, GraphQL, Bootstrap, Jest, Cypress...
React Native, React, Redux, GraphQL, Azure Active Directory B2C (ADB2C)...




Preferred Environment

Git, Visual Studio Code (VS Code), MacOS

The most amazing...

...thing I've coded is a collaboration app for remote teams, which has been adopted by renowned companies such as Alaska Airlines, Delta Air Lines, KFC, and more.

Work Experience

Senior Front-end Developer

2021 - 2023
  • Migrated legacy AngularJS to React, enhancing site performance. Received praise from both stakeholders and clients. Transformed AngularJS 1.6 code to React 18 incrementally, converting pages one by one and managing routing.
  • Developed UI components for company-wide design systems as a senior React developer, ensuring consistency and enhancing the user experience across websites and dashboards.
  • Maintained a legacy DNA testing platform's website built with AngularJS 1.6, Bootstrap, and .NET. Addressed user-reported bugs promptly and implemented requested features within the existing codebase.
  • Updated the admin dashboard, developed initially using AngularJS 1.6 and .NET, to seamlessly integrate new features introduced in the legacy website.
  • Updated their blog website, which was developed using WordPress. Added new pages to expand the content throughout the process and significantly updated the user interface to align with their specific requirements.
Technologies: CSS, React, REST APIs, Bootstrap, MobX, TypeScript, Storybook, Figma, Jest, Enzyme, Unit Testing, Tailwind CSS, WordPress, HTML, .NET, JavaScript, Next.js, Front-end Development, Full-stack, Material UI

Senior Front-end Developer

2019 - 2021
  • Played a significant role in developing a business insight news website and its accompanying dashboard, inspired by platforms like Bloomberg. Used Vue, Next.js, Vuex, TypeScript, Storybook, Jest, Cypress, GraphQL, and AWS Amplify.
  • Created a marketing site for an AI service as part of a side project. Used Vue, Next.js, Vuex, TypeScript, Storybook, Jest, Cypress, GraphQL, AWS Amplify, and LaunchDarkly.
  • Demonstrated effective collaboration with a team of six developers, delivering high-quality features and functionality for the website.
  • Participated in developing a wide range of elements, such as new web pages, paywalls, charts, email templates, caching mechanisms for the home page, UI components, and A/B testing functionalities.
  • Implemented performance optimizations, improving website speed and enhancing user experience. By implementing a cache mechanism, the loading time for the home page was reduced by 70%.
  • Developed email templates for the marketing team, conducted testing using Litmus, and seamlessly integrated them with Mailchimp.
Technologies: JavaScript, TypeScript, Vue, Nuxt.js, Vuex, GraphQL, Bootstrap, Jest, Cypress, Unit Testing, E2E Testing, Storybook, AWS Amplify, HTML, CSS, Front-end Development, CI/CD Pipelines, A/B Testing

Senior React and React Native Developer

2017 - 2019
  • Developed a highly successful mobile app that enables companies to manage and track remote teams seamlessly, with prominent clients including American Airlines, Delta Air Lines, Alaska Airlines, KFC, and more.
  • Contributed as a skilled React Native developer in the mobile app team and collaborated effectively with other teams, including back-end developers, designers, and QA engineers.
  • Took ownership of developing several critical features, including SSO, news bulletins with offline support, push notification, live chat, Beacon signal detection, and new screens.
  • Demonstrated strong technical skills and attention to detail, resulting in high-quality deliverables that met or exceeded client expectations.
Technologies: React Native, React, Redux, GraphQL, Azure Active Directory B2C (ADB2C), Firebase, Socket.IO, Selenium, Jenkins, Fastlane, CI/CD Pipelines, Jest, Enzyme, Amazon Web Services (AWS), Front-end Development

React and React Native Developer

2015 - 2017
Soka Co
  • Contributed to developing a fleet-based car-sharing mobile app, website, and dashboard, which helped the company grow to over six million subscribers in 2020.
  • Worked as a team member in both the web and mobile app development teams, collaborating with cross-functional teams to deliver quality products.
  • Developed key features, such as real-time tracking, feedback systems, live chat, and geolocation for the mobile MVP version of the app, which helped the company secure funding and expand.
  • Created various web pages for the website and dashboard, ensuring seamless integration with the mobile app.
  • Maintained a strong work ethic and a commitment to delivering quality work, leading to successful product launches and satisfied clients.
Technologies: Redux, React Native, Socket.IO, React, Payment APIs, Next.js, Bootstrap, JavaScript, Front-end Development

Full-stack Developer

2012 - 2015
  • Played a crucial role in continuously maintaining and updating the UI/UX for a renowned eCommerce website in Korea, acknowledged as a leading player in the industry.
  • Contributed to both front-end and back-end development teams, fostering collaboration with cross-functional teams to ensure the delivery of high-quality products.
  • Participated in developing a variety of charts and graphs on the admin dashboard using Highcharts, showcasing analytical insights into consumer behavior and trends.
  • Demonstrated strong back-end skills by developing various RESTful APIs for the eCommerce website.
  • Worked on developing a WordPress plugin for stock management using PHP—connecting Salesforce and getting data from it.
Technologies: CSS, JavaScript, HTML, REST APIs, Webpack, Bootstrap, Node.js, Payment APIs, Data Visualization, Highcharts, Front-end Development, Full-stack, WordPress, PHP, Express.js, MongoDB, PostgreSQL

Junior Web Developer

2011 - 2012
  • Acquired valuable practical experience and deepened understanding of software engineering beyond what can be learned in a university setting.
  • Gained insights and real-world experience into project management methodologies, communication within a team, overall software development lifecycle, software architecture, etc.
  • Worked on internal company projects, including developing a dashboard, tracking tool, and internal news and blogging website.
Technologies: CSS, JavaScript, HTML, Bootstrap, REST APIs, Web Project Management, Software Engineering, Agile, Front-end Development

Tellimer | Business Insight News Platform
A business insight news platform similar to Bloomberg, offering top-notch investment insights on the countries, companies, and sectors influencing emerging markets. It consisted of a news website for users and a dashboard for editors.

As a senior front-end developer, I contributed to doubling the user base through performance enhancements, UI updates, and the development of email templates with A/B testing.

Socar | Fleet-based Car-sharing Platform
A leading fleet-based car-sharing platform in Korea, surpassing six million subscribers in 2020.

As a team member in the web and mobile app development teams, I collaborated with cross-functional teams to deliver high-quality products, including the mobile app, website, and dashboard.

The React Native-based MVP of the mobile app that I developed played a crucial role in securing funding for the company and driving its continued growth.

Springshot | Collaboration App
Springshot is a collaboration app used by renowned enterprises such as KFC, Alaska Airlines, and Delta Air Lines, facilitating seamless management and tracking of remote teams.

As a senior React Native developer in the mobile team, I spearheaded the development of crucial features, including SSO, offline-supported news bulletins, push notifications, live chat, Beacon signal detection, and new screens.

My strong technical expertise and meticulous approach ensured the delivery of high-quality solutions that consistently met or surpassed client expectations.

Patreon | Membership Platform
A membership platform that empowers content creators to run subscription services by providing comprehensive business tools.

As a senior React developer, I designed and implemented captivating onboarding pages, ensuring a seamless user experience.

Furthermore, I applied my expertise to enhance the creator's dashboard, equipping them with powerful tools and intuitive interfaces for efficient subscription management and audience engagement.

Additionally, I made valuable contributions to the development of a diverse range of UI components, meticulously crafting visually appealing and highly functional elements that elevated the overall user interface of the platform.

Wemakeprice | eCommerce Platform
An eCommerce and marketplace platform recognized as one of the top marketplaces in Korea.

As a valued team member, I played a crucial role in maintaining and updating the UI/UX of the eCommerce website.

I actively contributed to both the front-end and back-end development teams, collaborating with cross-functional teams to deliver high-quality products.

Additionally, I participated in the development of diverse charts and graphs on the admin dashboard using Highcharts, presenting analytical insights on consumer behavior and trends.

Hover | House 3D Modeling Platform
A platform that converts house photos into accurate 3D models.

As a valuable team member, I collaborated with designers to implement animation, pixel-perfect designs, and responsive UI, resulting in a seamless user experience.

Taking ownership of the marketing website, I made strategic decisions on architecture, languages, libraries, and frameworks.

I developed global components and integrated them into the internal design systems, conducting rigorous unit testing to ensure their functionality. Additionally, I updated internal design system components and web pages to improve web accessibility, making them more inclusive.

Furthermore, I updated web pages on legacy WordPress websites, leveraging my technical skills and knowledge.

Working closely with multidisciplinary teams, including engineers, designers, and QA engineers, I ensured timely and high-quality project delivery on a daily and weekly basis.

Parsel | Website for AI Service to Analyze Documents
A website with membership, providing services to analyze documents using AI.

As the sole front-end developer in this project, I owned all front-end development tasks, from architecture design and language/framework selection to deployment and testing.

WordPress Website for Exome and Genome Testing
As a senior front-end developer, I updated a WordPress website for a company specializing in exome and genome testing. I added new pages to expand the content and significantly improved the user interface to meet their specific requirements.


JavaScript, TypeScript, HTML, GraphQL, SCSS, CSS, PHP, HTML5


React Native, Tailwind CSS, Redux, Next.js, Bootstrap, Jest, Cypress, Nuxt.js, Selenium, .NET, Material UI, Express.js


React, Vue, REST APIs, MobX, Socket.IO, Node.js, Highcharts, AWS Amplify, Vuex, Stripe


Figma, Azure Active Directory B2C (ADB2C), Jenkins, Fastlane, Webpack


Agile, E2E Testing, Test-driven Development (TDD), Unit Testing


Contentful, Amazon Web Services (AWS), Firebase, WordPress


Web Project Management, Software Engineering, Enzyme, Gatsby, Storybook, Front-end Development, CI/CD Pipelines, Payment APIs, Data Visualization, Chakra UI, Apollo, Axe, WCAG 2, Full-stack, A/B Testing, Front-end


MongoDB, PostgreSQL

2007 - 2010

Bachelor's Degree in Computer Engineering

Ajou University - Suwon, Korea





Business English Certificate

Cambridge English




MARCH 2011 - MARCH 2014



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