Jonathan Watt
Software Engineer at Mozilla Corporation
Manchester, England, United Kingdom
Summary
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SeniorJonathan Watt is a seasoned software engineer with 20 years' experience, based in Manchester, England, specializing in C++, SVG, HTML5, CSS and JavaScript. He has been a core contributor at Mozilla since 2008, working deeply on rendering and style systems for projects like Servo and Gecko where he implemented and refactored font and CSS layout handling. His work on Servo — a high-profile, parallel web rendering engine — demonstrates strong backend skills in memory-safe, modular browser components and cross-engine bindings. Jonathan combines long-term product experience with low-level, standards-oriented engineering, improving compatibility around shorthand properties and CSS @page rules. Colleagues rely on him for careful refactors and pragmatic typing improvements that reduce complexity across large codebases. He brings a rare mix of browser internals expertise and front-end styling knowledge that helps bridge rendering engines and web standards.
20 years of coding experience
3 years of employment as a software developer
Github Skills (14)
css10
rust10
layout-engine10
render10
rendering10
servo9
browser9
webengine8
documentation7
web-platform7
html6
c-language6
cprogramming-language6
javascript4
Programming languages (19)
Github contributions (5)
mozilla/gecko-dev
Jun 2011 - Jan 2023
Read-only Git mirror of the Mercurial gecko repositories at https://hg.mozilla.org. How to contribute: https://firefox-source-docs.mozilla.org/contributing/contribution_quickref.html
Role in this project:
Full-stack Developer
Full-stack DeveloperContributions:935 commits in 11 years 9 months
Contributions summary:Jonathan primarily contributed to the refactoring and renaming of CSS-related properties and values within the Gecko rendering engine. Their work involved renaming `position-try-options` to `position-try-fallbacks` and `inset-area` to `position-area`, as well as other related code adjustments across multiple files. Additionally, the user updated documentation and fixed links within the codebase, specifically related to Gecko Overview and MOTS pages. These changes indicate a focus on improving the CSS layout and rendering aspects of the Firefox browser.
repositoriesfirefoxmercurialgit-mirrormozilla
servo/servo
Mar 2018 - Jun 2018
Servo, the embeddable, independent, memory-safe, modular, parallel web rendering engine
Role in this project:Backend Developer
Backend DeveloperContributions:8 commits, 3 PRs, 7 comments in 3 months
Contributions summary:Jonathan primarily contributed to the Servo web rendering engine, specifically focusing on the style module and its interaction with Gecko bindings. They implemented and refactored features related to font handling, including font weight, font style, and font stretch, and updated the code to use user-defined types for these properties. They also addressed issues related to shorthand properties and the `@page` rule, modifying the codebase to support new CSS features and improve compatibility.
browserrustjavascriptbrowser-engineservo
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