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.
Portfolio
Experience
- HTML - 12 years
- React - 10 years
- Redux - 9 years
- Node.js - 9 years
- APIs - 8 years
- TypeScript - 8 years
- Python - 6 years
- D3.js - 5 years
Work Experience
Web Developer
Self-employed
- 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.
Full-stack Developer
Reddit, Inc.
- Created an Activation Hub page for new small and medium advertisers to help with onboarding and boost activations.
- Improved the ads platform with a variety of fixes to the front end.
- Built the groundwork for a new Shopify integration.
- Built the technical foundation for a new Shopify integration.
React/React Native Developer
ID Verifi Inc
- Built a B2B SaaS dashboard for identity verification using React and Material UI.
- Migrated the project from Create React App to Vite for improved performance and build efficiency.
- Tested components with Jest and React Testing Library.
Software Engineer
IntelliBridge
- Developed a new website for CMS (Centers for Medicare & Medicaid) using TypeScript, Next.js, React, RadixUI, and Contentful.
- Worked as an interim developer lead for eight months and managed two junior developers.
- Mentored a newly promoted intern to become a pivotal member of the development team.
- Collaborated with designers to refine Figma designs and graphic assets.
- Managed CI/CD pipelines using GitHub Actions and Jenkins.
- Handled an AWS infrastructure setup using CloudFormation, CloudFront, S3, and Lambda.
- Conducted unit testing with Jest and integration testing with Cypress with over 80% test coverage.
Senior React Developer
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.
Jinja2/HTML/CSS Developer
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.
Front-end React Developer
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.
Front-end Web Developer
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.
Web Development Intern
WUSB
- 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.
Android Developer
Self-employed
- 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.
Project History
Statistipedia Explore
Desktop Website
https://desktop.kenfehling.comNYC Real Estate
The dataset was created using Python, Pandas, Numpy, and Scikit-learn.
Education
Bachelor's Degree in Computer Science
Stony Brook University - Stony Brook, NY, USA
Skills
Libraries/APIs
React, Node.js, React Router, REST APIs, React Redux, D3.js, Lodash, jQuery, React Testing Library, 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, Reselect, Playwright, Lit
Tools
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, Jenkins, Amazon CloudFront, AWS CloudFormation, Inkscape, Astro, Prettier, Zapier, Auth0, Create React App, Grafana, Claude
Languages
HTML, CSS, JavaScript, Python, TypeScript, HTML5, Python 3, Java, SQL, Kotlin, Sass, Bash, Bash Script, Pug, JavaScript 5, Clojure, Ruby, Go
Frameworks
Redux, Jinja, Django, Material UI, Express.js, Flask, Next.js, Jest, Tailwind CSS, Android SDK, GeoDjango, Guice, Google Guice, Bootstrap, ClojureScript, React Native, Jakarta Server Pages (JSP), Ruby on Rails (RoR), Cypress
Paradigms
HTML DOM, Unit Testing, REST, Web App Design, Web UI Design, Responsive Web Design (RWD), Responsive Layout, Kanban, Functional Programming, Dependency Injection, Search Engine Optimization (SEO), UI Design, E2E Testing, Event-driven Programming, Testing
Platforms
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, AWS Lambda
Storage
PostgreSQL, MongoDB, Databases, PostGIS, SQLite, Relational Databases, MySQL, Google Cloud, Amazon S3 (AWS S3)
Other
Front-end, APIs, Web Development, Front-end Development, Dynamic Websites, Web Pages, Responsive UI, Single-page Applications (SPAs), 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, Vite, 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, Data Science, Statistics, Design, API Integration, Server-side Rendering (SSR), Data Processing, Architecture, CSS3 Animation, Cloudflare, Algorithmic Trading, GitHub Actions, Lambda Functions, Integration Testing, Nivo, CI/CD Pipelines, Web Components, Cursor AI, Gemini
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