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Jeffrey Sweeney
Verified Expert in Engineering
Software Developer
Bennington, NH, United States
Toptal member since June 26, 2019
Bio
Jeffrey is a software developer with over eight years of experience—comfortable with a myriad of tools and libraries (React 16, Redux, Redux-Saga, Vue/Vuex, TypeScript) and more than proficient with accessible HTML5, responsive CSS, and JavaScript on both the front and back ends. Jeffrey is also handy with Node.js, npm, Webpack, Babel, Express, Sass, and whatever else is needed to spin up a development environment, run tests, or deploy components.
Portfolio
Reddit, Inc.
Front-end, JavaScript, TypeScript, ECMAScript (ES6), CSS, GraphQL, APIs...
MDCalc Ltd, Inc.
PostgreSQL, React, Node.js, React Native, Next.js
Lumber Marketplace LLC
Node.js, React, JavaScript, Next.js, PostgreSQL, Prisma, Tailwind CSS
Experience
- JavaScript - 12 years
- HTML5 - 8 years
- CSS3 - 8 years
- Git - 8 years
- Web UX - 8 years
- Node.js - 6 years
- React - 5 years
- Web Accessibility - 3 years
Preferred Environment
Atom, Terminal, MacOS
The most amazing...
...things I've developed include a quick React-Redux app npm package that I used to build my personal website, as well as Swab.am, an SVG animation SPA.
Work Experience
Front-end Developer
2025 - 2025
Reddit, Inc.
- Reviewed and wrote onboarding documentation for internal projects.
- Assisted new hires in setting up their environments.
- Added features and fixed bugs within Reddit Pro and other parts of the Reddit website.
Technologies: Front-end, JavaScript, TypeScript, ECMAScript (ES6), CSS, GraphQL, APIs, Large-scale Projects, Lit, React, Vue, Angular, REST, HTTP
Full-stack Developer
2025 - 2025
MDCalc Ltd, Inc.
- Applied small fixes and enhancements to an existing established web and mobile platform.
- Reviewed and fixed reported website security issues.
- Architected, documented, and implemented changes to a subscription refund process.
- Improved the performance of the internal ad admin pages from 2.7 seconds to 7 seconds.
Technologies: PostgreSQL, React, Node.js, React Native, Next.js
Full-stack Node.js and React Developer
2024 - 2025
Lumber Marketplace LLC
- Architected and designed a Next.js and PostgreSQL SaaS SPA hosted on AWS.
- Implemented Stripe React components and integrated Stripe into a back-end Node.js application.
- Created database and unit tests in different sections of the application.
Technologies: Node.js, React, JavaScript, Next.js, PostgreSQL, Prisma, Tailwind CSS
Front-end React Developer
2024 - 2024
Montgomery Psychiatry
- Updated the internal application from React 16 to React 18.
- Created a dynamic multiple-choice mental health assessment form.
- Developed a static public website in Next.js for new patients and businesses.
- Created a mental health assessment that transforms into a human-readable report to be used by providers.
Technologies: React, Figma, HTML, CSS, JavaScript, Redux, PostgreSQL
Senior Software Engineer
2011 - 2024
Sorcero
- Led the front-end development of medical insights management.
- Reprogrammed the majority of the front end for intelligent publication monitoring.
- Created interactive timelines, maps, heat maps, line charts, and bar charts.
- Collaborated with product owners to define technical requirements.
- Worked with designers to convert mockups into application code.
- Wrote unit and automated tests using Jest and Playwright.
- Assisted in Python API development using PostgreSQL and SQLAlchemy.
Technologies: Vue, React, CanvasJS, Python, SQLAlchemy, Monorepos, Node.js
Full-stack Developer
2023 - 2023
Xplorstem
- Developed an authentication service for a Next.js/Express.js website.
- Integrated SendGrid to allow for account password reset.
- Added the ability to develop the application locally without relying on AWS using Docker and MySQL.
- Discussed approaches and best practices for other planned site features.
Technologies: React, Express.js, Next.js, Jest, API Integration, Full-stack Development, REST APIs
Web UI Developer
2022 - 2023
Shooting Academy Canada Ltd
- Developed interactive tools that allowed website visitors to customize and visualize strings for longbows, crossbows, etc. and create arrows for different bows.
- Created a tool for the client to customize the string-builder store options.
- Hooked up the string- and arrow-builder interfaces into Shopify via Shopify's front-end REST API.
- Investigated and fixed some minor issues related to various Shopify plugins.
Technologies: HTML, JavaScript, CSS, Shopify, API Integration, Full-stack Development
Front-end Developer
2021 - 2021
Imperial College London
- Refactored and recreated the front end of a bacteria querying tool using Create React App and Bootstrap. Added infinite scrolling logic and an about-info drawer to the common website banner.
- Developed an interactive histogram component from scratch for displaying information about bacterial isolates using the HTML5 Canvas.
- Created an interactive, easy-to-decipher species containment stacked bar graph from scratch using the HTML5 Canvas.
- Built an interactive, speedy gene visualizer that can render and display millions of entries of genomic information and an optimized, efficient table of species information with thousands of entries.
Technologies: JavaScript, React, Bootstrap, CSS3, Canvas 2D, Responsiveness
Full-stack Developer
2021 - 2021
Topshelling
- Developed the front end of a proof-of-concept (POC) web application for adding a listing and removing information about boutique items, such as their name, description, markdown, and picture.
- Hooked into HTML5 camera APIs, allowing users to either upload or take a screenshot of an item with their phone and add it to the product description.
- Created a POC back end in Node.js and Express.js for retaining information about boutique items in memory.
Technologies: Node.js, JavaScript, Snowpack, Express.js, Tailwind CSS, HTML5, Architecture, REST APIs
Front-end Engineer
2020 - 2021
Anthem [Now Elevance] - AI
- Developed and maintained a telehealth operating system, an RTC platform connecting doctors and patients from around the world.
- Integrated real-time communication and chat messaging with Twilio.
- Developed an application-guided tour with in-house React code.
- Converted Zeplin mockups into UI and common components.
Technologies: HTML, CSS, Sass, JavaScript, React, Front-end, Axios, REST APIs, Material UI
Freelancer | Consultant
2019 - 2020
Independent Freelance Work
- Created and recorded over six hours of JavaScript video tutorials.
- Converted static HTML/CSS into an interactive Vue.js/Vuex UI.
- Developed a deployment environment for maintaining a small website.
- Hooked into PHP Google Drive APIs to connect Google Docs and Google Calendar to a website.
- Consulted clients on best practices in regard to front-end technology and accessibility.
Technologies: Vuex, Vue, Babel, Webpack, Node.js, Redux, React, JavaScript, CSS3, HTML5, Architecture, REST APIs
Senior Front-end Developer
2013 - 2019
Avid Technologies
- Worked with a small team to develop the player, sequence, and audio components of Avid's MediaCentral | Cloud UX, a web app for browsing, playing, and logging media.
- Served as a scrum master for a year and a half, performing administrative duties and ensuring stakeholders were always informed about the team's status on features.
- Worked closely with the UI team, converting mockups and offering advice on accessibility and consistency with the rest of the application.
- Maintained our local RHEL development server by evolving our application's back end from Java to NGINX to Docker to Kubernetes.
- Wrote Node.js build and deployment scripts to allow us to release components regularly in an agile manner.
- Composed manual, unit, automated, and integration tests in Gherkin, Mocha, Jest, TestCafe, and a bit of Groovy Selenium.
Technologies: Babel, Webpack, NPM, Node.js, Express.js, Java, NGINX, Kubernetes, Docker, RHEL, Git, Jira, CSS3, HTML5, Redux, React, Preact, JavaScript, Architecture, API Integration, Responsiveness, REST APIs
Experience
Quick React-Redux App
A minimal bootstrapper for developing a static React-Redux web application that can quickly be built for the web.
Unlike other tools, this utility is not particularly married to a technology stack; due to the fact, it creates a project with very few dependencies, it does not suffer slowdowns typical in more heavy-handed bootstrappers.
There is also no eject step required to deploy for the web, just running "NPM run build" generates all the needed files.
This project has been field-tested in a number of my projects.
Unlike other tools, this utility is not particularly married to a technology stack; due to the fact, it creates a project with very few dependencies, it does not suffer slowdowns typical in more heavy-handed bootstrappers.
There is also no eject step required to deploy for the web, just running "NPM run build" generates all the needed files.
This project has been field-tested in a number of my projects.
Swab Animator
This project centers around an online web application to quickly create SVG animations in the browser.
It uses React and Redux to drive the UI and is architected in a declarative, event-sourced way that theoretically would allow for infinite undo or multi-user editing.
It uses React and Redux to drive the UI and is architected in a declarative, event-sourced way that theoretically would allow for infinite undo or multi-user editing.
Avid MediaCentral | Cloud UX
https://www.avid.com/products/mediacentral/mediacentral-acquireI worked with a small team in the development of the player, sequence, and audio components for Avid MediaCentral | Cloud UX. I had many other responsibilities revolving around the actual development, including QA, DevOps, UI design, and more.
Litify Referral Network
From the website:
"The Litify Referral Network is an all-in-one platform solution that allows law firms of all sizes to easily send, receive, and manage legal case referrals for FREE."
The front-end portion of this application is written in ReactJS with a small auxiliary Express server for serving mostly static content. My primary task was to clean up the front and back ends of this application for development and production.
I updated all of the npm dependencies (including updating to the latest versions of React and react-router) and refactored the build scripts and Express server to be as atomic and simple as possible. I also recreated a number of components, including a custom date picker and a brand new sign-up page and flow.
The application no longer has serious dependency vulnerabilities, is much leaner, and runs much faster.
"The Litify Referral Network is an all-in-one platform solution that allows law firms of all sizes to easily send, receive, and manage legal case referrals for FREE."
The front-end portion of this application is written in ReactJS with a small auxiliary Express server for serving mostly static content. My primary task was to clean up the front and back ends of this application for development and production.
I updated all of the npm dependencies (including updating to the latest versions of React and react-router) and refactored the build scripts and Express server to be as atomic and simple as possible. I also recreated a number of components, including a custom date picker and a brand new sign-up page and flow.
The application no longer has serious dependency vulnerabilities, is much leaner, and runs much faster.
Monadnock Congregational Church
This was a pet project where I migrated a basic server-side CMS website to a client-generated Nuxt and TailwindCSS site.
Noteworthy features are under the hood. The website can be updated and published with a single script, compiling the Vue.js templates and sending the files to the webserver via FTP with a custom node script. A small PHP script retrieves Google Calendar information.
Noteworthy features are under the hood. The website can be updated and published with a single script, compiling the Vue.js templates and sending the files to the webserver via FTP with a custom node script. A small PHP script retrieves Google Calendar information.
Strata — Raven Black
I developed sophisticated live and historic radar detection software with an expert team of fellow developers.
My responsibilities were primarily on the Vue.js and TypeScript-heavy front end, but I also started to work on their to-be-published Hugo website.
My responsibilities were primarily on the Vue.js and TypeScript-heavy front end, but I also started to work on their to-be-published Hugo website.
Transplant Services — Health Data Movers
https://www.healthdatamovers.com/services/clinical-business-applications/I worked with a small team of developers on the front end and back end of a web application that supported medical professionals in the corneal transplant industry through documentation of referrals, tissue recovery, and medical review. On the front end, I developed pages on React, Redux, and Material UI. On the back end, I modified and created services with Node.js, MySQL, Sequelize, WebSockets, and Twilio/SendGrid for sending notifications.
Sample Next.js Project
https://bitbucket.org/jsweeneydev/nextjs-sample-project/src/master/A basic project that showcases how Next.js 15, TypeScript, GraphQL, and a custom auth server can be built.
When run, a multi-page application allows users to create user or admin accounts and sign in.
When run, a multi-page application allows users to create user or admin accounts and sign in.
Education
2010 - 2012
Associate's Degree in Computer Science (Networking)
River Valley Community College - Claremont, NH, USA
Skills
Libraries/APIs
Vue, React Redux, React, Node.js, REST APIs, CanvasJS, Redux-Saga, Vuex, Preact, jQuery, React Router, Socket.IO, Google Drive API, D3.js, SQLAlchemy, Apollo Client, Lit
Tools
NPM, Babel, Webpack 4, Git, Mocha, Canvas 2D, Canvas, Redux Thunk, Adobe Illustrator, Adobe Photoshop, Rollup, GitHub, Terminal, Atom, Webpack, Jira, NGINX, Sequelize, SendGrid, Snowpack, Figma, Prisma
Languages
JavaScript, HTML5, CSS3, CSS, HTML, Gherkin, PHP 5, Sass, Hugo, TypeScript, Java, Python, GraphQL, ECMAScript (ES6)
Frameworks
Redux, Express.js, TestCafe, Jest, Material UI, Svelte, Nuxt.js, Tailwind CSS, Angular, Bootstrap, Next.js, React Native
Platforms
MacOS, Unix, Twilio, Docker, Kubernetes, Shopify
Paradigms
Functional Programming, Agile Software Development, REST
Storage
MySQL, MongoDB, PostgreSQL
Other
APIs, Web UX, Ajax, Fetch API, UI Development, Front-end, User Interface (UI), Architecture, API Integration, Responsiveness, WebSockets, Web Accessibility, Full-stack Development, Third-party APIs, Full-stack, CSS3 Animation, RHEL, SVG, Storybook, Axios, Monorepos, Development, Apollo Server, Large-scale Projects, HTTP
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