William Cox, Developer in Mesa, AZ, United States
William is available for hire
Hire William

William Cox

Verified Expert  in Engineering

Full-stack Developer

Mesa, AZ, United States
Toptal Member Since
August 4, 2021

Will taught himself JavaScript to build a CRM solution for a previous employer. The CRM prevented thousands of clients from slipping through their system. While this success saved the company millions of dollars, his greatest takeaway was his newfound love for programming. Seven years later, his motivation is the same–to build software that matters. Will aims to provide the highest quality product on the market while using the latest technologies in the industry.


Milliman, Inc. -- LTS
React, Redux, React Redux, Jest, UI Testing, Front-end, Angular, Playwright...
JavaScript, Node.js, Next.js, React, TypeScript, Sequelize, PostgreSQL, Stripe...
Next.js, Chart.js, Node.js, Express.js, MySQL, Heroku, React, REST APIs...




Preferred Environment

MacOS, Visual Studio Code (VS Code), MySQL Workbench, Adobe, Postman, React, Redux, TypeScript, Webpack, Node.js

The most amazing...

...experience I've had as a professional was migrating a PHP monolithic application to a Node.js microservices architecture.

Work Experience

Senior Front-end Developer

2022 - PRESENT
Milliman, Inc. -- LTS
  • Integrated AG Grid to replace their legacy component causing recurring bugs and re-renders. This isolated a lot of complex logic that wasn't fully unit tested.
  • Centralized many components into a shared library accessible to all their front-end applications. Incorporated the Carbon component library into these components and provided visual automated testing with Storybook.
  • Took time to ensure new and existing features had ample automated testing in each task. Used Jest to provide unit and integration testing and Playwright for E2E tests.
  • Iteratively migrated MobX-dependent components to Redux. Added custom middleware to allow both data management libraries to communicate and sync state.
Technologies: React, Redux, React Redux, Jest, UI Testing, Front-end, Angular, Playwright, RTK Query, AG Grid, TypeScript, Electron, CSS, CSS3, Material UI, HTML, HTML5, Styled-components, Carbon Design System, Azure, Storybook, Nx, Lodash, Redux Thunk, Babel, Webpack, Sass, SCSS, JSON

Senior Software Engineer

2021 - 2022
  • Architected and implemented a data feed ingestor and digestor. This back-end worker ingested updates from multiple third-party APIs with different properties and digested them into a headless REST API that fed our mobile and web apps.
  • Improved operations by introducing better practices like testing (Jest + React Testing Library), using a component library that I architected, eliminating bloatware, and spending time working on tech debt each sprint.
  • Brought design and engineering together to build a system that would foster a seamless transfer between the two groups. This was done through the use of Tailwind CSS, which enforced our shared design system.
Technologies: JavaScript, Node.js, Next.js, React, TypeScript, Sequelize, PostgreSQL, Stripe, REST APIs, Software Architecture, Elasticsearch, Amazon S3 (AWS S3), Tailwind CSS, Styled-components, Postman, Unit Testing, E2E Testing, CSS3, HTML5, Express.js, Google Analytics, Microservices, Customer Relationship Management (CRM), Babel, Webpack, Single-page Applications (SPA), HTML, CSS, Magic Link Authentication, Styled-jsx, SQL, Storybook, APIs, Web Design, User Experience (UX), User Interface (UI), Amazon Web Services (AWS), Jest, Front-end, UI Testing, Back-end, JSON, Full-stack

Full-stack Developer

2020 - 2021
  • Built a Next.js web application with server-side rendering to display marketing KPIs for franchisees that were learning how to run a business.
  • Wrote a RESTful API in Node.js with Express.js to serve live information from Google and Facebook Analytics.
  • Developed a UI and UX matching the company's brand and feel.
  • Incorporated a MySQL server to be the intermediary between third-party services and the front-end client.
Technologies: Next.js, Chart.js, Node.js, Express.js, MySQL, Heroku, React, REST APIs, Google Analytics, User Experience (UX), User Interface (UI), Socket.IO, Amazon S3 (AWS S3), HTML5, HTML, CSS3, CSS, Magic Link Authentication, Single Sign-on (SSO), Single-page Applications (SPA), Styled-components, Styled-jsx, Adobe, JavaScript, Babel, Webpack, Sass, SQL, SCSS, APIs, Web Design, Amazon Web Services (AWS), Front-end, Back-end, JSON, Full-stack

Full-stack Developer

2017 - 2019
Textile Graphix
  • Built a custom t-shirt design web application for bulk orders. Major clients included the Utah Jazz and universities.
  • Developed a PMS for the Textile Graphix administrative team.
  • Managed all aspects of technology in a startup environment.
Technologies: Node.js, MySQL, React, Express.js, Authorize.net, Lodash, Moment.js, React Redux, Redux Thunk, Babel, Webpack, Sass, Product Management, Single Sign-on (SSO), Single-page Applications (SPA), HTML, HTML5, CSS, CSS3, Adobe, JavaScript, REST APIs, Content Management Systems (CMS), SQL, SCSS, Redux, APIs, Web Design, User Experience (UX), User Interface (UI), Front-end, Back-end, JSON, Full-stack

Software Engineer

2017 - 2019
Career Step
  • Rearchitected the legacy platform from PHP to Node.js to make it microservices-oriented.
  • Managed four learning management systems, including a legacy system, a new system, and two third-party systems.
  • Maintained 10+ Angular web apps, including a shopping cart, an admin app, and lead generation landing sites.
  • Integrated Salesforce within Career Step's platform.
Technologies: PHP, Node.js, MySQL, Apache, Apex, Salesforce, Angular, Microservices, Learning Management Systems (LMS), Express.js, Amazon S3 (AWS S3), Content Management Systems (CMS), eCommerce, Babel, Single Sign-on (SSO), Single-page Applications (SPA), HTML, HTML5, CSS, CSS3, Adobe, Postman, Unit Testing, E2E Testing, JavaScript, REST APIs, Moment.js, Sass, SQL, SCSS, APIs, Amazon Web Services (AWS), Jest, Front-end, UI Testing, Back-end, JSON, Full-stack

Junior Full-stack Developer

2017 - 2017
  • Assisted Devmountain with migrating its database to Salesforce.
  • Built a housing portal for use by management and tenants.
  • Was hired to assist with teaching students after completing an intensive JavaScript certification.
Technologies: Node.js, MySQL, React, Salesforce, Express.js, Adobe, HTML5, HTML, CSS, CSS3, React Redux, Redux Thunk, Single Sign-on (SSO), Single-page Applications (SPA), Postman, JavaScript, REST APIs, Webpack, SQL, Redux, MongoDB, PostgreSQL, APIs, Web Design, User Experience (UX), User Interface (UI), Front-end, Back-end, JSON, Full-stack

PV Design Manager

2013 - 2016
Vivint Solar
  • Established and managed six state offices comprising a team of 24 CAD technicians.
  • Programmed a small CRM that saved the company’s most important offices from failure.
  • Worked with state offices to create accurate drawings in compliance with electrical, building, and fire codes.
Technologies: JavaScript, Excel VBA, Customer Relationship Management (CRM), Adobe, HTML, HTML5, CSS, CSS3, Front-end, Back-end

Marketing KPI Dashboard

A Next.js and React app with a Node.js and Express.js RESTful API created for a local marketing company that uses KPIs when coaching franchise owners. I designed and developed the entire dashboard web app, which includes a magic link authentication flow, permission management, email notifications, and more.

Textile Graphix Sandbox

A React front end with a Node.js and Express.js back end. This was my first experience with eCommerce, and I also created a PMS that allowed the company's administrative team to dynamically update the online store.

Electron Fortnite Ranking App

A desktop app I built with Electron using React. Nite Ladder is a Windows PC Fortnite plugin used to rank players in the competitive community. I wrote a replay file parser to find statistics like eliminations and placements and created a ranking system with that data.

React Native NBA Player Ranking App

A React Native mobile app for Android and IOS that displayed live stats for NBA players and ranked them. I wrote a Node.js service that would maintain a live response from a third-party API that ultimately fed my headless API that my client subscribed to.
2014 - 2016

Coursework Toward Bachelor's Degree in Computer Science

Brigham Young University - Provo, UT, USA


JavaScript Certification



JavaScript Web Development



Node.js, React, React Redux, Socket.IO, Lodash, Moment.js, Styled-jsx, REST APIs, Chart.js, Authorize.net, Stripe, Playwright, AG Grid


Git, Redux Thunk, Babel, Webpack, Adobe, Postman, Apache, Google Analytics, Sequelize, RTK Query


Next.js, Express.js, Electron, Tailwind CSS, Redux, Angular, Jest, React Native, Material UI


CSS3, HTML5, JavaScript, Sass, HTML, CSS, TypeScript, SCSS, SQL, C++, Java, PHP, Apex, Excel VBA


Unit Testing, E2E Testing, Microservices


MacOS, Heroku, Amazon Web Services (AWS), Salesforce, Azure


Amazon S3 (AWS S3), JSON, MySQL, PostgreSQL, MongoDB, Elasticsearch

Industry Expertise

Web Design


Single Sign-on (SSO), Single-page Applications (SPA), APIs, Front-end, Back-end, User Experience (UX), User Interface (UI), Learning Management Systems (LMS), Customer Relationship Management (CRM), Content Management Systems (CMS), Product Management, Magic Link Authentication, Styled-components, Storybook, UI Testing, Full-stack, eCommerce, Software Architecture, Carbon Design System, Nx

Collaboration That Works

How to Work with Toptal

Toptal matches you directly with global industry experts from our network in hours—not weeks or months.


Share your needs

Discuss your requirements and refine your scope in a call with a Toptal domain expert.

Choose your talent

Get a short list of expertly matched talent within 24 hours to review, interview, and choose from.

Start your risk-free talent trial

Work with your chosen talent on a trial basis for up to two weeks. Pay only if you decide to hire them.

Top talent is in high demand.

Start hiring