Charlie Humphreys
Senior Software Engineer at Mozilla
Nashville-Davidson, Tennessee, United States
Summary
🤩
Rockstar🎓
Top SchoolCharlie Humphreys is a Senior Software Engineer with 11 years of experience building both front-end and back-end systems, currently contributing to Mozilla’s mobile efforts. He brings strong systems-level Rust and Kotlin skills alongside extensive Java, TypeScript, and web UI experience, with a track record of shipping features and telemetry integrations for Firefox for Android (Fenix) and application services. Charlie’s background spans clinical web apps and AI-adjacent backend work from roles at Vanderbilt, Digital Reasoning, and Smarsh, showing an ability to move between high-compliance domains and consumer product codebases. An active open-source contributor, he’s implemented Nimbus experimentation, behavioral targeting, and editor UX improvements (e.g., CodeMirror enhancements) across well-known repos. He also has a practical engineering curiosity—he once built a Raspberry Pi Hadoop cluster during university—which reflects a hands-on approach to solving infrastructure and tooling problems.
11 years of coding experience
9 years of employment as a software developer
High School Diploma, High School Diploma at Franklin Classical SchoolSoftware Engineering, Software Engineering at Lipscomb University
Stackoverflow
799reputation
60kreached
5answers
4questions
Github Skills (41)
kotlin10
javascript10
mobile-development10
testing10
android-development10
mobile-application10
firefox10
front-end-development10
nimbus10
android10
rust10
codemirror10
telemetry10
react10
jexl9
Programming languages (11)
Github contributions (5)
naturalcrit/homebrewery
Nov 2021 - Jan 2023
Create authentic looking D&D homebrews using only markdown
Role in this project:
Front-end Developer
Front-end DeveloperContributions:172 reviews, 163 commits, 45 PRs in 1 year 2 months
Contributions summary:Charlie primarily focused on enhancing the user interface of the D&D homebrew creation tool. Their work involved implementing a code folding feature for improved readability within the markdown editor. They integrated and configured various CodeMirror addons to enhance the user experience, including features for code search, auto-closing tags, active line highlighting, and handling trailing whitespace. In addition, they also addressed various code style-related improvements, making it easier to read and understand the codebase.
markdown-onlystylesheetrpghomebrewerymarkdown
mozilla/application-services
Jul 2022 - Jan 2023
Firefox Application Services
Role in this project:Back-end Developer
Back-end DeveloperContributions:1 release, 367 reviews, 16 commits in 5 months
Contributions summary:Charlie primarily contributed to the Firefox Application Services backend, focusing on features related to experiment management, Nimbus, and application services. They implemented functionality for behavioral targeting, including interval counters and event store queries. The user also modified code related to database migrations and API definitions. This demonstrates a strong understanding of the backend infrastructure and related technologies utilized by the repository.
firefoxpushfxasync
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