Robert Longson
Volunteer Contributor at Mozilla
United Kingdom
Summary
🤩
Rockstar🎓
Top SchoolRobert Longson is a seasoned software engineer and engineering leader with 19 years of experience building and scaling mission-critical systems across finance, utilities, and publishing. He has led large teams and cultural transformations—from waterfall to agile—and launched labs serving millions of requests while maintaining a hands-on approach to architecture, CI/CD automation, and microservice delivery. An active long-term volunteer contributor to Mozilla, he has made 600+ contributions to Firefox’s Gecko engine and web-platform-tests, specializing in SVG rendering, text layout and browser styling—work that impacts one of the web’s most widely used engines. His background spans back-end and front-end work, rescuing troubled programmes (including a rearchitecture of an ML trading compliance system) and delivering robust enterprise solutions. With an MSc in Computing and a pragmatic, people-focused leadership style, he combines deep technical expertise with a talent for mentoring and practical process improvements. An interesting detail: he remains a core SVG reviewer for Mozilla, blending open-source stewardship with applied product and platform experience.
19 years of coding experience
30 years of employment as a software developer
MSc, Computing, MSc, Computing at The University of ManchesterBSc, Mathematics and Physics, BSc, Mathematics and Physics at Durham University
Stackoverflow
121,246reputation
7.6mreached
2,337answers
0questions
image
top-1%
fonts
top-5%
background-color
top-5%
canvas
top-5%
animation
top-1%
dom
top-5%
Github Skills (56)
webbrowser10
javascript10
c-language10
servo10
jquery10
animation10
image10
testing10
css10
safari10
browser10
webengine10
colors10
tooltip10
gradient10
Programming languages (12)
Github contributions (5)
mozilla/gecko-dev
Oct 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:434 commits in 11 years 4 months
Contributions summary:Robert primarily contributed to the Mozilla Gecko browser engine, working on SVG-related features and bug fixes. Their contributions included simplifying antialiasing code, ensuring SVG attribute values are not zoomed, and adjusting viewBox values for CSS zoom. They also addressed bugs related to the display of symbol elements within masks and pattern elements and corrected text positioning to respond to CSS zoom.
repositoriesfirefoxmercurialgit-mirrormozilla
web-platform-tests/wpt
Jan 2016 - Jan 2023
Test suites for Web platform specs — including WHATWG, W3C, and others
Role in this project:Front-end Developer
Front-end DeveloperContributions:13 reviews, 26 commits, 19 comments in 7 years 1 month
Contributions summary:Robert primarily contributes to the web platform tests for the WPT project, focusing on SVG and related technologies. Their work involves implementing and testing features related to SVG elements, including `<use>`, `<image>`, `<feImage>`, animations, text rendering, and styling. They are responsible for adding support for new features like the 'lighter' composite mode and the 'turn' units in SVG, as well as fixing and improving tests for existing functionalities.
microsoft-edgetest-runnerspecssafarifirefox
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