Callie Holmes
I build accessible, performant, and secure digital experiences for the web.
About
I'm a full stack engineer (with a passion for front end, specifically) focused on creating intuitive and efficient user interfaces. I love working between UX design and UX engineering with clean, scalable code, but I'm not afraid to get my hands dirty with the API either. Historically, I've worked with DustJS, Mustache, Handlebars, ReactJS, and AngularJS. While I am most at home in TypeScript, I have also proven my chops with C++, C#, Java, and Python.
Currently, I am a senior Front End Engineer at Adapter Group. I work on (almost) all aspects of our web application, having driven a migration to a TurboRepo monorepo using Vite, ReactJS, TypeScript, and TailwindCSS 4. I have also worked with our product team to lead the development side of creating our component library and design system, as well as writing guidelines for AI coding companions to ensure standards regardless of who touches the code. I have also pushed for accessibility across the team and testing standards.
Previously, I've also worked at Microsoft, Amazon, Wowhead, Ask.com, and various other small-to-medium organizations. While I have a lot of experience with greenfield development, brownfield and legacy projects have also significantly impacted my career.
Outside of work, you might find me streaming my coding and gaming on Twitch, riding horses badly, exploring new projects, or making yet another build in Factorio.
Experience
Adapter Group
Senior Full Stack Engineer (Front End)
Architected and lead implementation of greenfield front-end stack using TurboRepo, Vite, React, and Tailwind, establishing monorepo package boundaries and building pipeline conventions across shared ui, state, and type packages
Built core chat interface for an AI agent product end-to-end, including smooth in-app animations preserving component state and updates with React Router - a key feature for the application’s beta that contributed to securing several multi-million dollar investment rounds
Developed UX patterns and engineered guidelines for human-AI interaction flows, including conversational chat interfaces and user-agent creation workflows
Integrated Python API backend with TypeScript front-end, owning full request lifecycle from front-end state management through API layer coordination
Introduced regression, integration, and unit testing practices into the codebase, reducing regressions and establishing a baseline for sustainable development velocity that also shaped future testing strategies
Microsoft: Copilot Studio UX
Software Engineer II (Full Stack)
Dedicated engineer for greenfield project of migrating Nuance codebase into Copilot Studio UX codebase in TypeScript, React, CSS-in-JS, and Playwright/React-Testing-Library.
Optimized UX telemetry, reducing customer friction by 20%, enabling data-driven prioritization through monitors and telemetry.
Lead mentorship programs, enhancing team and group-wide code quality and testing adoption.
Microsoft: Office Growth User Lifecycle
Software Engineer II (Full Stack)
Led customer checkout UI migration to React/TypeScript, improving performance and maintainability.
Delivered new features and optimizations from the React front-end to the C# backend
Rebuilt Playwright automation suite, saving 100+ engineering hours per sprint, and reducing costs by an estimated $10k+ per month.
Conducted training and knowledge presentations for 30+ engineers across the organization, increasing adoption of engineering excellence practices and testing.
Amazon AWS: AWS GameSparks
Front End Engineer II (Full Stack)
Key engineer for a greenfield project starting from ground 0 to create AWS GameSparks within AWS GameTech.
Developed front-end coding standards, improving code maintainability & performance.
Mentored interns and early-in-career engineers, leading to at least 5 full-time hires and 2 promotions.
Migrated testing framework to Cypress, cutting test execution time by 40% while also increasing coverage to 90%+.
Amazon Alexa: Alexa Machine Learning
Front End Engineer II (Full Stack)
Built Conflict Detection and language authoring tools in React/Redux to allow data scientists to optimize Alexa skill creation.
Maintained existing language authoring tools in Ruby-On-Rails with a Java API.
Lead and delivered migration from Ruby-On-Rails to React/Redux on the front end, while also pushing for correct MVC standards within the application business logic.
Mentored engineers for career growth, supporting multiple promotions.
Wowhead: ZAM Network
Web Developer (Data, Full Stack)
Developed initial MVP for real-time game data monitoring for World of Warcraft using Angular and NodeJS.
Brainstormed, designed, and conceived toolsets for processing large data sets that often changed on a weekly basis.
Reverse-engineered Blizzard's World of Warcraft executable to extract and visualize game updates for users around the globe (C++, Lua, Java/Kotlin).
Ask.com: ConsumerSearch
Front end engineer
Migrated Java-based sites to NodeJS as a fresh, greenfield project, improving scalability.
Led UX modernization to a mobile-first, responsive design.
Provided training and documentation for our UX and front-end solutions, including guidance for proper front-end practices.