Guillaume Demesy is a French software engineer and founder with 13 years of hands-on experience building web applications and running Splitfire as CEO since 2012. He combines full-stack development skills with entrepreneurial leadership, shipping pragmatic solutions for clients while continuing to contribute to open-source tooling. Notably, he enhanced Rome’s developer toolchain by implementing granular CSS vendor-prefix support for properties like border-radius and backdrop-filter, demonstrating attention to cross-browser UX details. Trained in mathematics and computer science, he brings a methodical, test-driven approach to front-end challenges and a personal commitment to balancing craft with family life.
13 years of coding experience
1 year of employment as a software developer
Licence, Mathematics and Computer Science, Licence, Mathematics and Computer Science at Université Henri Poincaré, Nancy 1
IUT Charlemagne
Développeur Logiciel, Développement Logiciel, Développeur Logiciel, Développement Logiciel at Centre Afpa Pompey
Unified developer tools for JavaScript, TypeScript, and the web
Role in this project:
Front-end Developer
Contributions:6 reviews, 6 commits, 6 PRs in 5 days
Contributions summary:Guillaume focused on enhancing the Rome tools by adding CSS prefix support. Their contributions include implementing features for `position`, `box-sizing`, `border-radius`, `animation`, `backdrop-filter`, and `user-select`. The code changes involved modifications to the `index.ts` file, as well as creating and updating files for individual CSS properties within the `prefixes` directory to handle vendor prefixes. Test fixtures within the `test-fixtures` directory were also updated to reflect the changes.
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Guillaume Demesy - CEO, Software Engineer at Splitfire