Ken Fehling, Developer in Honolulu, United States
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Ken Fehling

Verified Expert  in Engineering

Front-end Developer

Honolulu, United States
Toptal Member Since
August 19, 2022

Ken is a full-stack developer with a focus on front-end development with React. He has over 10 years of experience in web dev with HTML/CSS/JavaScript and 7 years with React and Redux. On the back end, he has primarily worked with Node.js, Django, Flask, and SQL databases like PostgreSQL, MySQL, and SQLite. Although not a designer, Ken has worked on UI/UX for several front-end web and mobile projects with UI frameworks like Bootstrap and Material UI, as well as from scratch with CSS and Sass.


JavaScript, HTML, CSS, React, Redux, Django, PostgreSQL, SQL, PostGIS, Pandas...
Get It Live LLC
Next.js, React, Material UI, TypeScript, Single-page Applications (SPA)...
Orita Inc.
HTML, CSS, Jinja, JavaScript, Python, Flask, Tailwind CSS, Figma...




Preferred Environment

React, Redux, HTML, CSS, JavaScript, TypeScript, Python, Web Development, D3.js, Web

The most amazing...

...application I've developed is a dashboard for data visualization using a React and D3.js front end and a Django and PostGIS back end.

Work Experience

Web Developer

2014 - PRESENT
  • Worked on many full-stack projects, from the design to the back end.
  • Used D3.js and visx to create interactive web-based data visualizations.
  • Created a custom CMS and static site generator for freelance clients based on Django, Django admin, and Django-distill.
Technologies: JavaScript, HTML, CSS, React, Redux, Django, PostgreSQL, SQL, PostGIS, Pandas, NumPy, Node.js, TypeScript, React Native, Express.js, Kotlin, SQLite, Lodash, HTML5, Sass, Flask, React Router, FFmpeg, Front-end, Relational Databases, Relational Database Design, Full-stack, Git, GitHub, GitHub Pages, Functional Programming, MongoDB, Mongoose, Data Visualization, APIs, REST, REST APIs, Software, Software Engineering, jQuery, React DnD, JSX, Gatsby, Next.js, Bootstrap, Bootstrap 4, Bash, Bash Script, Shell, Shell Scripting, MERN Stack, Python, Docker, Trello, MySQL, Jinja, Storybook, 2D Games, Netlify, Vercel, Web Development, Databases, Raspberry Pi, React Motion, Responsive Design, Google Cloud Platform (GCP), Google Cloud, Adobe Illustrator, Vector Graphics, PiLLoW, PIL, Image Processing, Python 3, Django ORM, Front-end Development, Web Scraping, Dynamic Websites, Web App Design, Web, Back-end, Web Pages, Responsive UI, User Interface (UI), Web UI, Web UX, DigitalOcean, Search Engine Optimization (SEO), Visual Studio Code (VS Code), Single-page Applications (SPA), Redux Thunk, HTML DOM, Material UI, React Redux, D3.js, SVG, Kanban, NPM, UI Design, Web UI Design, User Experience (UX), Responsive Web Design (RWD), Responsive Layout, Documentation, Technical Documentation, Tailwind CSS, SQLAlchemy, Styled-components, Figma, Web Applications, Web Programming, Jakarta Server Pages (JSP), Server-side JavaScript, Server-side Rendering (SSR), API Integration, Design, Ruby, Ruby on Rails (RoR), Webhooks, CSV, Data Processing, Scripting, Automation Scripting, Architecture, Full-stack Development, Contentful, Sanity Studio, CSS3 Animation, Algorithmic Trading

Senior React Developer

2023 - 2023
Get It Live LLC
  • Consulted on issues such as image optimization and performance.
  • Diagnosed performance issues using Chrome and React developer tools.
  • Analyzed Next.js bundle and suggested optimizations.
Technologies: Next.js, React, Material UI, TypeScript, Single-page Applications (SPA), Cloudflare, Trello, GitLab, Node.js, Sentry, Redux

Jinja2/HTML/CSS Developer

2022 - 2023
Orita Inc.
  • Implemented a new front end based on Figma designs for AI business SaaS customers.
  • Created Jinja2 templates using Tailwind CSS and JavaScript with a Python and Flask back end.
  • Worked with the designer, suggesting improvements to the UI/UX.
Technologies: HTML, CSS, Jinja, JavaScript, Python, Flask, Tailwind CSS, Figma, Web Applications, Web Programming, Webhooks

Front-end React Developer

2022 - 2022
Solvent Holdings Corp
  • Implemented a new reporting interface, including graphs, tables, and customized filter components.
  • Refactored legacy React class-based components to function components with hooks.
  • Reduced the number of component re-renders, improving performance and user experience.
  • Introduced Storybook to the project and used it for newly created components.
Technologies: Front-end, JavaScript, React, Python, Django, PostgreSQL, Data Visualization, D3.js, Chart.js, Redux, Storybook, React Final Form, React Redux, HTML5, Git, Kanban, React Router, JSX, NPM, Web Development, Web, Web Pages, Single-page Applications (SPA), HTML DOM, UI Design, Web UI Design, User Experience (UX), Web Applications, Web Programming, Design

Front-end Web Developer

2015 - 2017
TLT Media Lab, Stony Brook University
  • Designed and developed web-based education software systems for faculty and staff with feedback from stakeholders.
  • Created web-based games for researchers to use in studies with student volunteers.
  • Helped improve lab operations by introducing version control (Git), Kanban boards, and modern JavaScript tooling.
  • Introduced React and helped several team members learn it. Also taught Redux and other related libraries.
Technologies: JavaScript, SVG, React, Redux, Firebase, jQuery, Git, Trello, Webpack, Kanban, Unit Testing, Front-end, GitHub, REST, APIs, REST APIs, Software, Software Engineering, JSX, Bash, Bash Script, Shell, Shell Scripting, Linux, Python, Lodash, HTML5, React Router, React DnD, 2D Games, Web Development, Heroku, Responsive Design, Adobe Illustrator, Vector Graphics, Image Processing, Python 3, Front-end Development, Dynamic Websites, Web App Design, Web, Web Pages, Responsive UI, User Interface (UI), Web UI, Web UX, Web App UX, Web App UI, Single-page Applications (SPA), HTML DOM, React Redux, NPM, UI Design, Web UI Design, User Experience (UX), Google Web Designer, Web Applications, Web Programming, Design, CSV, Scripting, Architecture

Web Development Intern

2016 - 2016
  • Began a project to rewrite the radio station’s website and playlist system from scratch, providing a CMS for admins and DJs to use.
  • Worked on both the front-end templates and back-end Node.js code.
  • Created a CMS with KeystoneJS and MongoDB for radio DJs to add program playlists.
Technologies: JavaScript, Pug, KeystoneJS, MongoDB, HTML, HTML5, JavaScript 5, Gulp, NPM, Bower, Express.js, Git, GitHub, Mocha, Full-stack, Web Development, Databases, MERN Stack, Responsive Design, Front-end Development, Dynamic Websites, Web, Back-end, Web Pages, Responsive UI, Web UI, DigitalOcean, Node.js, HTML DOM, UI Design, Web UI Design, Web Programming, Server-side JavaScript, Architecture, Full-stack Development

Android Developer

2010 - 2014
  • Published a fairly successful app for video editing built on FFmpeg and Android NDK.
  • Implemented dependency injection and created testable modules using Google Guice and RoboGuice.
  • Moved into cross-platform development; picked up React Native, beginning a seven-year love affair with React.
Technologies: Android, Java, Android SDK, Android NDK, SQLite, RoboGuice, Guice, Google Guice, Dependency Injection, Git, Software, Software Engineering, AdMob, Google AdMob, Google Play API, Google Play Store, GitHub, Relational Databases, Relational Database Design, Mobile UX, Mobile UI, Mobile, Apps, Databases, App UI, App UX, UI Design, User Experience (UX), Design

Statistipedia Explore
A web-based data visualization dashboard. It presents the data in a number of plot types like bubble, line, bar, and map and slices the data by different combinations of features. The app's UI is focused on being as simple and minimal as possible, providing sensible defaults and avoiding overload.

Personal Website
A React-based homepage with a unique design. On the desktop, it resembles a macOS interface; on mobile, it resembles a mobile app UI. Two custom React libraries were developed and published as open source—one built on top of a React Router to handle nested history (used by the different windows and tabbed navigation) and one for creating custom audio players built with higher-order components used in the player for my created music.

NYC Real Estate
An interactive web-based data visualization of New York City real estate prices using D3.js. Includes linking and brushing features created with DC.js and Crossfilter.

The dataset was created using Python, Pandas, Numpy, and Scikit-learn.
2015 - 2022

Bachelor's Degree in Computer Science

Stony Brook University - Stony Brook, NY


React, Node.js, React Router, REST APIs, React Redux, D3.js, Lodash, jQuery, Pandas, NumPy, Ramda, History API, FFmpeg, React DnD, RoboGuice, Google Play API, Scikit-learn, React Motion, PIL, PiLLoW, Django ORM, Chart.js, React Final Form, SQLAlchemy


JSX, Redux Thunk, Figma, Git, Trello, Webpack, GitHub, GitHub Pages, Mongoose, Android NDK, Shell, Gulp, NPM, Bower, Mocha, Adobe Illustrator, Google Web Designer, Adobe Photoshop, GitLab, Sentry, GarageBand, Logic Pro


Redux, Jinja, Django, Material UI, Express.js, Flask, Next.js, Tailwind CSS, Android SDK, GeoDjango, Guice, Google Guice, Bootstrap, ClojureScript, Jest, React Native, Jakarta Server Pages (JSP), Ruby on Rails (RoR)


HTML, CSS, JavaScript, Python, TypeScript, HTML5, Python 3, Java, SQL, Kotlin, Sass, Bash, Bash Script, Pug, JavaScript 5, Clojure, Ruby


HTML DOM, REST, Web App Design, Web UI Design, Responsive Web Design (RWD), Responsive Layout, Kanban, Unit Testing, Functional Programming, Dependency Injection, Search Engine Optimization (SEO), UI Design, Data Science


Web, Visual Studio Code (VS Code), Contentful, Linux, Android, Docker, Firebase, Mobile, KeystoneJS, Netlify, Vercel, Raspberry Pi, Heroku, Google Cloud Platform (GCP), DigitalOcean, Sanity Studio


PostgreSQL, MongoDB, Databases, PostGIS, SQLite, Relational Databases, MySQL, Google Cloud


Front-end, APIs, Web Development, Front-end Development, Dynamic Websites, Web Pages, Responsive UI, Single-page Applications (SPA), Web Applications, Web Programming, Server-side JavaScript, Scripting, SVG, Full-stack, Digital Audio Workstations (DAW), Software, Software Engineering, MERN Stack, Storybook, Responsive Design, Back-end, Multimedia, Documentation, Technical Documentation, Styled-components, Webhooks, CSV, Automation Scripting, Full-stack Development, Visx, GeoPandas, TopoJSON, Higher Order Components, Maps, Geospatial Data, Data Visualization, Relational Database Design, Music, AdMob, Google AdMob, Google Play Store, Mobile UX, Mobile UI, Apps, Gatsby, Bootstrap 4, Shell Scripting, GeoJSON, 2D Games, Vector Graphics, Digital Art, Image Processing, Minimum Viable Product (MVP), Startups, Web Scraping, Video Editing, User Interface (UI), App UI, App UX, Web UI, Web UX, Web App UX, Web App UI, User Experience (UX), Algorithms, Data Structures, Networking, Statistics, Design, API Integration, Server-side Rendering (SSR), Data Processing, Architecture, CSS3 Animation, Cloudflare, Algorithmic Trading

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